samedi 6 septembre 2008

Lupus 6

Alpha Lupi (α Lup / α Lupi) est l'étoile la plus brillante de la constellation du Loup. C'est une étoile variable de type Beta Cephei.

Beta Lupi (β Lup / β Lup) is a Class B2III, third-magnitude star in the constellation Lupus. It is given the Chinese proper name Kekouan, meaning "Cavalry Officer", which is a name it shares with Kappa Centauri.[1] It lies close to the supernova remnant of SN 1006.
This star is a blue giant, located about 525 light-years from Earth.

Gamma Lupi (γ Lup / γ Lup) is a Class B2IV, third-magnitude star in the constellation Lupus. It is sometimes called by the Greek proper name Thusia, meaning "The Sacrifice" or Thusia Theriou, meaning "The Animal Sacrifice".
This star is a blue giant, located about 565 light-years from Earth.

Delta Lupi (δ Lup / δ Lup) is a Class B2IV, third-magnitude star in the constellation Lupus. It is sometimes called by the Greek proper name Hilasmus (ιλασμος), meaning "The Propitiation".
This star is a blue-white subgiant, located about 510 light-years from Earth.

Lupus 5

This constellation seems to have been an unidentified animal for both the Greeks and Romans, simply known as Therion. Both cultures thought Centaurus was offering this animal as a sacrifice. By the time Johann Bayer published his catalogue of constellations in the early seventeenth century, the animal was considered a wolf.
Lupus or the wolf. Filomeleo son of Demeter and Yasonte was the first agriculturist of the world according to Greek mythology. It seems to be that his Licaón grandfathers invited to Zeus to a banquet and he served to him to his own Arcade grandson like food. Zeus recomposed theA body of this one and he turned it star, Arcturus (a Bootis); but according to another version after recomposing the body of Arcade occurred it to raise to a goatherd and punished to the grandfathers turning it a wolf or Lupus and setting afire its mansion.

Lupus, is precious austral constellation that crosses the parallel of 40º of South latitude. One is in a rich zone in stars since it is practically in the equator of the Milky Route, therefore we can observe great amount of stellar and globular clusters. He is visible in the South hemisphere during the months of February to October and in the North hemisphere it culminates to very little distance of the observable horizon during the month of June, is easy to identify it if we left from Scorpius and we observed the Eastern zone of the same one.

Lupus limits the north with the constellations from Scorpius and Libra to the east with Centaurus, the south with Circinus and the west with the constellations of Norma and Scorpius again.

Lupus I located the 2 to it of May of 1986 at the age of 19 years from the locality of Cán Picafort, Majorca, Spain, logically, where I write these lines to you from the parallel +40º of North latitude Lupus it culminates to few degrees of the horizon and is observable the North zone of the constellation; I hope in future trips to be able to contemplate it completely.

Main stars

Alpha, a; of magnitude 2.29 and blue color. Earth light is to 548 years, is a blue giant 2800 times more shining than our Sun.

Beta, b; of magnitude 2.68 and blue color. One is another blue supergiant 1800 times more luminous than our Sun that is to 524 years Earth light.

Gamma, g; about 2.78 magnitude and also blue color is a blue supergiant 1900 times more luminous than the Sun that dista of us 174 years light.

Other objects

NGC 5824, precious globular cluster of magnitude 9.0 of 6' of diameter arc, is to 80,000 years Earth light. One is located in the North zone near Libra.

NGC 5986, precious globular cluster of magnitude 7.1 of 6' of diameter arc, is to 34,000 years Earth light. One is in the central zone of the constellation.

NGC 5927, precious globular cluster of magnitude 8.3 of 12' of diameter arc, is to 29,000 years Earth light. One is closely together in the South zone of the constellation of the constellation of Norm.

NGC 5749, stellar cluster of magnitude 8.80 of 8' of diameter arc that is to 2900 years light of us. It has a considered age of 91 million years. It is formed by star of the tenth and eleventh magnitude. It is located closely together to the south of the constellation of the limit with the constellation of Norma.

Lupus 4

The constellation may refer to the ancient king of Arcadia, King Lycaon (a word which is related to both 'wolf' and 'light').
King Lycaon, who ruled Arcadia with his fifty sons, was said to continue the practice of human sacrifice when other parts of Greece had abolished it as barbaric.
One variation of the story has King Lycaon offering Zeus the sacrifice of a young boy, which angered Zeus so much he promptly changed Lycaon into a wolf and struck his house down with lightning, killing all his fifty sons.
In another version Zeus one day visited Arcadia disguised as a simple traveller. Lycaon and his sons offered him soup made not only from the meat of goats and sheep, but also of his own son Nyctimus. Zeus overthrew the table in disgust and killed all the king's sons with lightning bolts (restoring the life of Nyctimus in the process).
While it may seem ludicrous to memorialise this barbaric King of Arcadia, even prior to the Greeks the constellation seems to have represented a sacrificial animal of some sort.
The asterism is not very obvious, and in fact the constellation itself is fairly difficult to separate from its closest neighbour Centaurus.
Lupus is narrowly squeezed between Centaurus and Hydra to the west, Scorpius and Norma to the east. Although small, since it lies in the Milky Way it is packed with interesting items, especially double stars.

The Bayer stars are generally third and fourth magnitude. To locate Lupus, one might first begin with the arms of Centaurus (if need be, one can review this constellation from the Archives). Starting at theta Centauri starhop to phi Centauri then eta and finally kappa Centauri.
In the same field to the south is beta Lupi, which at 2.7 magnitude is slightly brighter than kappa Centauri (3.1). Now drop down to the southwest some five degrees and you'll find alpha Lupi.
Alpha Lupi (a beta Cephei variable) is the brightest star of the constellation at 2.3 magnitude. There is some dispute over its distance; some authorities put it at 430 light years, while others at around 620. From the absolute magnitude of -4.4, it would have a distance of 710 light years.

Double stars in Lupus:
Gamma Lupi is a very close binary with a nearly edge-on orbit whose period is 147 years. Currently the companion is at the greatest distance: PA 274º, separation 0.68".
Epsilon Lupi is also a close binary: 3.4, 5.5; 247º, 0.6".
Eta Lupi is a pleasant fixed binary with slight colour contrast: 3.4, 7.8; 20º, 15".
Kappa1 and kappa2 form a wide fixed binary: 3.9, 5.7; 144º, 27".
Mu Lupi is a multiple system. AB: 5.1, 5.2; 142 degrees, 1.2". The third component is much easier: PA 130º, 24".
Xi1 and xi2 Lupi are a fixed pair. This double is the most attractive binary in Lupus: 5.3, 5.8; 49º, 10.4".

Variable stars in Lupus:
Lupus has three beta Cephei variables among its Bayer stars.
Beta Cephei variables are pulsating variables (prototypes are beta Cephei and beta Canis Majoris). These are massive and very luminous stars which rapidly rotate. The range of magnitude change is very small.
Alpha Lupi: 2.29-2.34; period 6h14m.
Delta Lupi: 3.2-3.24; period 3h58m.
Tau1 Lupi: 4.54-4.58; period 4h15m.

Lupus 3

The Wolf

Origin of the Constellation

The Wolf is usually pictured as hanging from a pole carried by the Centaur, which is the next constellation to the west. The writers of classical times considered this area of the sky to be part of the Centaur. They considered this area of the sky to represent an unspecified beast being carried by the Centaur. According to Ridpath it was only in Renaissance times that the constellation become identified with a wolf.
There seems to be no classical mythology connected with this dim area of the sky

Lupus 2

The ancient Greeks called this constellation Therium, representing an unspecified wild animal, while the Romans called it Bestia, the Beast. It was visualized as impaled on a long pole called a thyrsus, held by the adjoining constellation of Centaurus, the Centaur. Consequently, the constellations of the Centaur and the animal were usually regarded as a combined figure.

According to the historian George Michanowsky in his book The Once and Future Star, the Babylonians knew this constellation as UR-IDIM, meaning ‘wild dog’. Eratosthenes said that the Centaur was holding the animal towards the altar (the constellation Ara) as though about to sacrifice it. Hyginus referred to the animal as simply ‘a victim’, while Germanicus Caesar said that the Centaur was either carrying game from the woods, or was bringing gifts to the altar. The identification of this constellation with a wolf seems to have started in Renaissance times.
One is tempted to recall the story of Lycaon, king of the Arcadians, who served Zeus with the flesh of the god’s own son and was punished by being turned into a wolf (see Boötes). But that story has no connection with this constellation, which seems to have been overlooked by the mythologists. The fact that it is an imported constellation probably explains why the Greeks had no myths for it. None of the stars of Lupus have names.

Lupus 1

Lupus is a southern constellation.

Lupus has no extremely bright stars, but has around thirty stars of second and third magnitude and 70 of greater than sixth, including a number of binary or multiple stars. Among the stars which make up the constellation figure, only a few are named stars, the brightest is α Lupi, or Men, a blue giant. β Lupi has the name Ke Kouan. Most of the brightest stars in Lupus are massive members of the nearest OB association: Scorpius-Centaurus.

Towards the north of the constellation are globular clusters NGC 5824 and NGC 5986, and close by the dark nebula B 228. Two open clusters are to the south of the constellation, NGC 5822 and NGC 5749. On the western border are two spiral galaxies and the Wolf-Rayet planetary nebula IC 4406, containing some of the hottest stars in existence. Another planetary nebula, NGC 5882, is towards the centre of the constellation. The transiting exoplanet Lupus-TR-3b lies in this constellation.

The constellation has no clear mythology, but is sometimes associated with the tale of King Lycaon. Although known from ancient times no particular animal was associated with it until the Latin translation of Ptolemy's work identified it with the wolf. It was not separated from Centaurus until Hipparchus of Bithynia named it Therion (meaning beast) in the 200s BC. Prior to its separation it was considered an asterism of Centaurus, and was considered to have been an arbitrary animal, killed, or about to be killed, on behalf of, or for, Centaurus. As such, together with other constellations in the Zodiac sign of Virgo (specifically, Sagitta, and Centaurus) it may have formed the basis of the tale of the Erymanthian Boar, one of The Twelve Labours of Heracles.

Cepheus 8

Alderamin (α Cephei) est la plus brillante étoile de la constellation de Céphée. Son nom vient de l'arabe الذراع اليمن (Al Dhira al Yamin), qui signifie « le Bras droit » (son emplacement correspond au bras droit de Céphée).
C'est une étoile blanche en fin de vie. Plus grande et plus massive que le Soleil, elle possède plusieurs compagnons stellaires.
Une de ses singularités est sa vitesse de rotation inhabituellement élevée (246 km/s à l'équateur), qui lui permet d'exécuter un tour complet sur elle-même en moins d'une demi-journée. Par comparaison, le Soleil y met près d'un mois. Chez les autres étoiles de cette catégorie, la gravité tend à séparer les éléments lourds des éléments légers, en concentrant les premiers vers le centre. Dans le cas de Alderamin, la vitesse de rotation semble empêcher le phénomène. L'activité magnétique que laissent supposer les rayonnements émis est également inattendue pour ce type d'étoile. Ces anomalies restent mal comprises à l'heure actuelle.
De par la précession des équinoxes, Alderamin deviendra l'étoile la plus proche du Pôle nord céleste, à moins de 3°, dans quelques 5500 ans.

Beta Cephei (β Cep / β Cephei) est une étoile de la constellation de Céphée. Elle porte également le nom traditionnel Alfirk (arabe الفرقة al-firqah), qui signifie "Le troupeau" (référant à un troupeau de moutons).
Beta Cephei est le prototype des étoiles variables de type Beta Cephei. Sa magnitude apparente varie entre +3,15 et +3,21 sur une période de 0,1904844 jours. Elle est de type spectral B2IIIev et est à environ 595 années-lumière de la Terre.

Gamma Cephei (γ Cep / γ Cephei) est une étoile de la constellation de Cephée. Elle porte également le nom traditionnel Alrai,également orthographié Errai (ou Er Rai).
Gamma Cephei est une étoile binaire située à environ 50 années-lumière de la Terre et ayant une magnitude apparente de 3,22. L'étoile la plus grosse et la plus brillante est une sous-géante orange de type spectral K1 IV. La plus petite est une naine rouge dont l'orbite a été peu étudiée : la meilleure estimation actuelle est qu'elle parcourt une orbite excentrique de 10 à 29 UA sur une période de 70 ± 16 ans, avec une excentricité de 0,439 ± 0,06 (Cochran et al 2002).
Gamma Cephei est l'étoile visible à l'oeil nu qui remplacera α Ursae Minoris comme étoile polaire nord de la Terre, à cause de la précession des équinoxes. Alrai deviendra plus proche du pôle nord céleste que α Ursae Minoris autour de l'an 3000, et sera à son point le plus proche aux environs de 4000. Le "titre" passera à ι Cephei aux environs de 5200.
Le nom traditionnel provient de l'arabe الراعي ar-rā‘ī, qui signifie "le berger". De manière ambigüe, l'étoile β Ophiuchi est également parfois appelée Alrai, mais est plus connue sous le nom de Cebalrai ou Kelb Alrai, signifiant "le chien de berger".

Delta Cephei (δ Cep / δ Cephei) est une étoile dans la constellation de Céphée.
Delta Cephei est un prototype de Céphéides, de par son nom propre Latin Cepheidus Prototypus, et elle est aussi l'étoile la plus étroite du type du Soleil. Sa variabilité a été découverte par John Goodricke en 1784, ce qui en fait la seconde Céphéide découverte après Eta Aquilae, plus tôt la même année.
A la différence d'Algol, une étoile binaire à éclipses, la variabilité de Delta Cephei est due aux pulsations de l'étoile. Elle varie d'une magnitude de 3,6 à 4,3, et son type spectral fluctue également entre F5 et G3. La période est de 5,36634 jours ; l'évolution vers le maximum est plus rapide que le déclin vers le minimum. Plus tard, on a découvert qu'il y a deux types de Céphéides, et Delta Cephei est connue à ce jour comme étant de type I (classique).
On pense que les étoiles de ce type se forment avec des masses allant de 3 à 30 fois celle du Soleil, puis passent dans la séquence principale comme des étoiles de type B. Avec l'hydrogène se consumant en leur cœur, ces étoiles instables sont à présent passées à travers un stade plus avancé de combustion nucléaire.
La connaissance de la distance de Delta Cephei et des autres dans son type, est essentielle pour calibrer leur rapport période-luminosité ; malheureusement, ces efforts ont été troublés jusqu'à maintenant par l'exactitude du parallaxe. Cependant, en 2002, le télescope spatial Hubble a été utilisé pour déterminer la distance de Delta Cephei (et de RR Lyrae, une autre chandelle standard) dans ~4% : 273 parsecs, ou 890 années-lumière.
Il y a un compagnon à cette étoile, séparé de Delta Cephei de 41 secondes d'arc.

θ Cephei Al Kidr; دوتایی طیفی

μ Cephei (Herschel's) Garnet Star, Erakis; متغییر نیمه‌منظم

ν Cephei Cor Regis; ستاره متغییر; چندستاره

ξ Cephei component of the ξ Cep system; دوتایی طیفی

κ Cephei سه ستاره

υ1 Cephei دوتایی گرفتی

Cepheus 7

If not very bright, the constellation is still quite noticeable, just to the west of Cassiopeia's chair. The stars are mostly third and fourth magnitude.
The constellation has numerous binaries, several significant variables, and a few interesting deep sky objects.

Alpha Cephei is known as Alderamin ("The Right Shoulder"). In another 5500 years this will become the Pole Star.
Beta Cephei is called Alfirk ("The Herd"). This is a visual binary as well as a variable (see below).
Gamma Cephei is Er Rai (Shepherd). Long before Aldemarin becomes the Pole Star, this one will assume that title (around 4000 AD).
Delta Cephei is a prototype for one of the more significant types of variables (see below). The star is also a very fine binary with a colour contrast.
Mu Cephei is a brilliantly coloured star, a deep red which moved William Herschel to call it "The Garnet Star". The colour depends on the size of one's telescope; the larger scopes bring out an orange element. It is also a semiregular variable (see below).

Double stars in Cepheus:
The constellation has a number of very fine binaries, some quite easily resolved by small scopes, others rather more difficult.
Beta Cephei is a blue giant with a faint companion easily resolved: 3.2, 8; PA 250º, separation 13.6"
Delta Cephei is a fixed double, a yellow giant with blue companion: 3.8, 7.5; PA 191º, separation 41".
Xi Cephei is considered to be the most attractive binary in Cepheus, a blue-white primary and yellow (or reddish) companion that orbits every 3800 years: 4.4, 6.5; PA 275º, separation 8.2". 6.5;
Kruger 60 is a famous binary only 12.9 light years away, comprised of two red dwarfs. Observers had reported seeing flare-ups on the surface of the companion, which is orbiting the primary every 44.6 years.
AB: 9.8, 11.4; presently the companion is at PA 109º and separation 3.2".
The binary is less than one degree SSW of delta Cephei. Burnham has a finder's chart (p. 600).
Struve 2816 is a multiple binary, a very attractive triple:
AC: 6.3, 8.1; 121º, separation 11.7" D: 8.0; PA 339º, 19.9"
In the same field are Struve 2813 and Struve 2819, all centred in the middle of the large but faint diffuse nebula IC 1396, just south of mu Cephei.

Variable stars in Cepheus:
Beta Cephei is the prototype of a class of pulsating variables. These are hot, luminous, and very massive stars with a specral type of O9 to B3. The group is also called 'beta Canis Majoris' stars, for this star too is a member of the group. Indeed, it is the brightest member of the group.
The variations in visual magnitude are of very small amounts, barely as much as a quarter of a magnitude. Beta Cephei varies only 0.04 magnitude from its typical brightness of 3.2 and a period of 4 hours 34 minutes.
Delta Cephei is also the prototype of a class of variables.
Delta Cephei variables are immensely useful stars. Studies of the period of pulsation and the apparent magnitude led investigators to devise a method of gauging the distance to outlying galaxies (the so-called period-luminosity relation).
Delta Cephei varies from 3.48 to 4.37 every 5 days, 8 hours, 47 minutes, 31.9 seconds. This means its maximum brightness can be calculated with a reasonable degree of accuracy.
After the maximum is reached, a gradual diminuition of magnitude occurs over the next three days, only for the star to again increase over the following two days until it again reaches its maximum.
Comparing its magnitude with zeta, just to the west, will tell you if it has reached its brightest. Zeta has a visual magnitude of 3.4, while delta Cephei varies from 4.4 to 3.5. That is, for most of its cycle, it will be rather more dim than zeta, but as it reaches its maximum, it should appear to have a magnitude quite similar to its neighbour.
Mu Cephei is a semiregular supergiant that also varies roughly from 4.5 to 3.5, with a very long period: 730 days.
S Cephei is a long-period Mira-type variable, 7.4-12.9, with a period of 486 days. In the year 2000 the maximum should occur in late January or early February.
T Cephei is also a long-period Mira-type variable, ranging from 5.2 to 11.3 every 388 days. It should reach a maximum in the last week of December of 1999.

Cepheus 6

Cepheus is the name of two mythological kings. One was the son of Aleus, from Arcadia. He would become the king of Tegea (a community on the Peloponesian peninsula), would father twenty children, and would sail with Jason as an Argonaut.
The other Cepheus was the son of Belus, king of Egypt (who was himself the son of Poseidon). This Cepheus grew to become the King of Ethiopia (or Joppa). He married Cassiopeia and they had a daughter Andromeda. (Yes, the whole family eventually winds up in the heavens.)
Cassiopeia was incredibly beautiful but immensely vain. She was also proud of her daughter's beauty. In fact she continually boasted that the two of them were more beautiful than any of the fifty sea nymphs who attended Poseidon's court.
These nymphs (the Nereids) complained to Poseidon, who felt he had to defend his own reputation. So he sent a flood to devastate Cepheus' kingdom. The oracles told Cepheus that in order to save his people he must sacrifice his daughter to a great sea monster: Andromeda was tied to a rock along the coastline, dressed only in her jewellery. The monster would be along in due time to take his prize.
At that moment Perseus came flying by. He had just killed the Gorgon Medusa and was carrying the severed head back to Athene.
Medusa was one of the three Gorgon sisters; they were once very beautiful but Medusa slept one night with Poseidon, in Athene's temple. This infuriated Athene so much she turned Medusa's hair to snakes and turned her into a terrifying monster with huge teeth and claws. One look from Medusa would turn the viewer to stone.
With the assistance of Athene, Medusa's sworn enemy, Perseus tricked Medusa by looking at her reflection. He then sliced off her head (Pegasus and a warrior named Chrysaor sprang fully-formed out of Medusa's dead body).
So Perseus arrives at the scene and has a quick chat with Cepheus and Cassiopeia; it is agreed that should he rescue their daughter, he can marry her. So he skims across the water and his shadow on the waters confuses the monster, which Perseus then beheads.
Far from delighted, Cepheus and Cassiopeia balk at their daughter marrying Perseus. However Andromeda insists, so the marriage ceremony is performed on the spot.
Halfway through the ceremony Agenor, a family relative, shows up and claims Andromeda as his bride. (It's pretty certain now that Cassiopeia put him up to it.) Understandably, this angers Perseus and a great battle breaks out. However, outnumbered, Perseus has to resort to desperate measures. So he shows Medusa's head, instantly turning everyone to stone, including Andromeda's parents.
Poseidon then put Cepheus and Cassiopeia into the heavens, but with a twist: he made the vain Cassiopeia spin around on her chair, spending half the year upside down. As for Cepheus, Poseidon gave him a number of medium sized stars that go to make his square face with a pointed crown.

Cepheus 5

When Nereids overheard Cassiopeia she became very jealous. She complained to Poseidon, God of the Sea, and demanded that Cassiopeia be punished. Poseidon agreed and summoned a terrible sea-monster, Cetus. "Go to the coast of Cassiopeia's land," Poseidon directed, "and lay waste to the land, and kill the people, and kill the cattle." Cetus, in the form of a monstrous whale, set upon his mission of destruction and began the slaughter, working his way up and down the coast. The frightened people gathered and pleaded to their king to save them. Cepheus consulted an oracle--one with magical powers who could communicate with the gods when men sought their advice. The oracle told Cepheus that there was only one way to stop the slaughter: "You must offer your daughter Andromeda as a sacrifice." She was to be chained to the rocks on the coast and left for Cetus to devour. He made the bitter choice of sacrificing Andromeda, whereupon she was chained to the rocks and abandoned to await Cetus. When Cetus discovered the prize awaiting him, he left off his wholesale destruction of the land and began swimming toward the ledge where Andromeda was chained. But then a distant figure appeared in the sky. It was Perseus, the brave son of Zeus and Danae, just returning from a journey during which he had succeeded in killing the dreaded Medusa. It was when Perseus was flow over the coast of Æthiopia that he noticed Andromeda chained to the rocks by the sea, and not far away he could see Cetus rapidly nearing her. Down he swept to the girl's side. "Why are you thus bound?" he asked, overwhelmed by Andromeda's beauty. Andromeda told him the story of her boastful mother and the advice the oracle had given her father. Perseus quickly turned to Cepheus and said: "I can save your daughter from the sea-monster, but for my reward I demand Andromeda's hand in marriage, and a kingdom." Cepheus promised Perseus that he would have what he asked for, whereupon Perseus unsheathed his sword and leapt into the air to the attack. One thrust of his sword found a soft spot between the armored scales of the monster. Wounded, it twisted over on its side. Perseus then inflicted another deep cut, and another. Blood now colored the water red and soaked Perseus' winged shoes. Fearful of losing his ability to fly, he settled on a rock near the shore and waited for the sea-monster to attack again. As it did, Perseus' sword plunged deeply into the monster's evil heart. Joyful beyond words, Cepheus and Cassiopeia led Perseus and Andromeda to their house, where a great feast and celebration were prepared. Perseus and Andromeda were married and led a long, happy life together. There first-born son, Peres, is said to have given rise to those people who became known as Persian. When Perseus and Andromeda died, they were given honored places among the stars by the goddess Athena. Cetus, the sea-monster, was there waiting for them and forever chases Andromeda around the sky, but Perseus continues to guard her well. Meanwhile Cepheus and Cassiopeia had died and were likewise given honored places among the stars by Poseidon.

Cepheus is among the oldest constellations in the northern sky and played an important part in Greek mythology. In early Greek times Cepheus was known as the father of the Royal Family.

Cepheus was King of Æthiopia (not present day Ethiopia), and the beautiful Cassiopeia was his Queen. Soon after their marriage, Cassiopeia bore her husband a daughter, Andromeda. Cassiopeia was vain and boastful. So great was her beauty and that of Andromeda, she said, that it surpassed even that of Nereids (the Sea-goddess).

Chinese mythology also gives Cepheus and honored place in the sky, where he is known as Tsao Fu, the famous charioteer of around 950 B.C.

Instead of seeing Cepheus as the King, Arabian nomads saw a shepherd, his dog and his sheep.

Cepheus 4

Alpha Cephei

Distance (Light Years) 48.80 ± 0.36
Visual Magnitude 2.45
Color (B-V) 0.22

Names For This Star

The name of this star is derived from the Arabic phrase Al Dhira al Yamin meaning "The Right Arm". This would be apparently the right arm of the king whom the constellation represents.
The name of the star may also be written as "Alderaimin."

Description of the Star

Alderamin is a white A7V main sequence star. From the spectral type a temperature of about 8100 K may be inferred. The star would be probably about 1.5 times larger in diameter than the sun and maybe 9 times more luminous.

Cepheus 3

The King

The Brighter Stars of Cepheus

The Story
The Kingdom of Ethiopia

King Cepheus was the King of Ethiopia, which in Greek myth, according to Ridpath, was conceived to be a country stretching from Palestine down to the shores of the Red Sea and included parts of present-day Israel, Jordan and Egpt.
The Vanity of Cassiopeia

Cepheus was descended from Zeus, and the offspring that resulted from Zeus' liason with Io. Cepheus wife Cassiopeia was very beautiful, but very vain as well. She had the presumption to compare her beauty with that of the Nereid sea nymphs. Poseidon punished her pride by sending the sea monster Cetus to ravage Ethiopia.
Sacrificing the Maiden

Cepheus sent to the Oracle at Ammon to learn what he must do to appease the anger of the god. He was told that he must offer his virgin daughter Andromeda as a human sacrifice. She was to be chained to a rock on the Mediterranean Coast and left for the monster to devour.
Perseus Saves the Day

Cepheus did as he was told, but the hero Perseus showed up. He slew the monster and released Andromeda from her chains. Perseus claimed Andromeda's hand in marriage. King Cepheus was agreeable, but there was a problem. Cepheus had already promised Andromeda to his brother Phineus.
The Bloody Engagement Dinner

Phineus showed up with numerous followers at the engagement banquet for Andromeda and Perseus. So Perseus had to prove his heroism once more by battling for the right to marry his betrothed. The banquet turned into a bloody battle royal, where Perseus slaughtered Phineas and all of his followers.

Cepheus 2

Cepheus was the mythological king of Ethiopia. He was deemed worthy of a place in the sky because he was fourth in descent from the nymph Io, one of the loves of Zeus – and having Zeus as a relative was always an advantage when it came to being commemorated among the constellations. The kingdom of Cepheus was not the Ethiopia we know today, but stretched from the south-eastern shore of the Mediterranean southwards to the Red Sea, an area that contains parts of the modern Israel, Jordan and Egypt. Ptolemy described him as wearing the tiara-like head-dress of a Persian king.

Cepheus was married to Cassiopeia, an unbearably vain woman whose boastfulness caused Poseidon to send a sea monster, Cetus, to ravage the shores of Cepheus’s kingdom. Cepheus was instructed by the Oracle of Ammon to chain his daughter Andromeda to a rock in sacrifice to the monster. She was saved by the hero Perseus, who killed the monster and claimed Andromeda for his bride.
King Cepheus laid on a sumptuous banquet at his palace to celebrate the wedding. But Andromeda had already been promised to Phineus, brother of Cepheus. While the celebrations were in progress, Phineus and his followers burst in, demanding that Andromeda be handed over, which Cepheus refused to do. The dreadful battle that ensued is described in gory detail by Ovid in Book V of his Metamorphoses. Cepheus retired from the scene, muttering that he had done his best, and left Perseus to defend himself. Perseus cut down many of his attackers, turning the remainder to stone by showing them the Gorgon’s head.
The constellation of Cepheus lies near the north celestial pole. Its most celebrated star is Delta Cephei, a pulsating supergiant star that varies in brightness every 5.4 days. It is the prototype of the Cepheid variable stars that astronomers use for estimating distances in space.

Cepheus 1

Cepheus is a northern constellation named after Cepheus, King of Aethiopia in Greek mythology, and is considered to represent a king. It is one of the 88 modern constellations, and was also one of the 48 listed by Ptolemy.

When including fainter stars, visible to the naked eye, Cepheus appears with a crown (upside down with respect to the ecliptic). Together with other constellations nearby (Andromeda, Perseus, Cassiopeia, and possibly Pegasus), and the constellation Cetus below Cepheus, this may be the source of the myth of the Boast of Cassiopeia, with which it is usually identified.

vendredi 5 septembre 2008

Piscis Austrinus 5

Fomalhaut (α Piscis Austrini) est l'étoile la plus brillante de la constellation du Poisson austral, et la 17e étoile la plus brillante du ciel nocturne. Son nom provient de l'arabe فم الحوت fum al-ħūt, ce qui signifie « la bouche du poisson ».
Il s'agit d'une étoile de la séquence principale, de type spectral A, située à environ 25 années-lumière du système solaire.
Il semble que Fomalhaut soit une étoile relativement jeune, âgée de seulement 200 à 300 millions d'années, et dont la durée de vie ne devrait pas dépasser le milliard d'années. Sa composition chimique est identique à celle du Soleil.
Fomalhaut est entourée d'un disque de poussières en forme de tore dont le bord intérieur se trouve à environ 133 ua (1 ua = distance Terre-Soleil, soit 150 000 000 de km) de l'étoile, soit plus de trois fois la distance du Soleil à Pluton. Ce disque a une largeur d'environ 25 ua, un diamètre de 20 milliards de km et son centre géométrique se trouve décalé de près de 15 ua de Fomalhaut ; il est parfois appelé la ceinture de Kuiper de Fomalhaut. Il semble que des planètes se soient déjà formées autour.
Fomalhaut est une des quatre « étoiles royales » des Perses, il y a environ 5 000 ans.

To confirm:
Piscis Austrinus contains within its borders approximately 15 visible stars. The principal star of Piscis Austrinus is El Rischa. The brightest of Piscis Austrinus's stars is Lacaille 9352 (10.74 ly). Piscis Austrinus also contains within its boundries the following noteworthy stars: Fomalhaut.
The rope

β Piscis Austrinus: Tien Kang.

Piscis Austrinus 4

Piscis Austrinus, also known as Piscis Australis, is a fish drinking the waters pouring from the jars of Aquarius. The constellation was known in ancient times, and is said to be the original "Pisces". It is thought that the constellation referred to the Assyrian fish god Dagon and the Babylonian god Oannes. Even the Arabs called the constellation Al Hut al Janubiyy, the Large Southern Fish.

Piscis Austrinus, also known as Piscis Australis, is a fish lying on its back, drinking in the waters pouring from the jars of Aquarius. The asterism leaves a lot to the imagination.
The constellation was known in ancient times, and is said to be the original "Pisces". It is thought that the constellation referred to the Assyrian fish god Dagon and the Babylonian god Oannes. Even the Arabs called the constellation Al Hut al Janubiyy (The Large Southern Fish).
The bright star Fomalhaut (alpha PsA) was so named from Fum al Hut, meaning "The Fish's Mouth", although it carried many other names as well, including Al Difdi al Awwal ("The First Frog"). There are several fine binaries here, as well as a red dwarf with the fourth highest proper motion. Except for Fomalhaut, all other stars in this constellation are fourth or fifth magnitude.

Double stars:
Piscis Austrinus has several visual binaries, either fixed or moving very slowly.
Beta PsA is a fixed binary: 4.5, 7.5; 172 degrees, 30.4".
Delta PsA is a fairly wide but faint binary: 4.5, 10; 244 degrees, 5".
Gamma PsA: 4.5, 8.5; 262 degrees, 4.3".
Eta PsA: 5.5, 6.5; 116 degrees, 1.6".

Variable stars:
Piscis Austrinus has no notable variables.

Piscis Austrinus 3

Piscis Austrinus
The Southern Fish

The Brighter Stars of Piscis Austrinus

Origin of the Constellation

There is little classical mythology associated with the Southern Fish. According to Ridpath, the fish is associated with the Syrian Fertility Goddess Atagartis, who fell into a lake near the Euphrates River and was saved by a large fish.
The Southern Fish is always shown with its mouth open drinking the water pouring from the jar of Aquarius. According to Staal, the fish is often seen as a sign of salvation in the legends of a great deluge. The fish drinks the waters of the flood to save the world.

The Southern Fish is sometimes seen as the parent of the two fish of Pisces.

Alpha Piscis Austrini

Distance (Light Years) 25.1 ± 0.2
Visual Magnitude 1.17
Color (B-V) 0.09

Names For This Star

The name "Fomalhaut" derives from an Arabic name for this star:Fum al Hut meaning "The Fish's Mouth."
The alternative Latin names for the star, Os Piscis Meridiani or Os Piscis Notii mean "The Mouth of the Southern Fish."

The name Difda al Auwel or Al Difdi` al Awwal is "The First Frog." The Second Frog is Diphda, Beta Ceti.

Description of the Star

Fomalhaut is a white A3V main sequence star having about 1.7 times the diameter of the sun and about 17 times the luminosity. The spectral type implies an effective temperature of 9100 K and a mass of about 2.6 solar masses.
Fomalhaut is the nearest young star to us, where planets appear to be forming. There are also images of dust discs around Fomalhaut and other stars.

Piscis Austrinus 2

Eratosthenes called this the Great Fish and said that it was the parent of the two smaller fishes of the zodiacal constellation Pisces. Like Pisces, its mythology has a Middle Eastern setting that reveals its Babylonian origin. According to the brief account of Eratosthenes, the Syrian fertility goddess Derceto (the Greek name for Atargatis) is supposed to have fallen into a lake at Bambyce near the river Euphrates in northern Syria, and was saved by a large fish. Hyginus says, in repetition of his note on Pisces, that as a result of this the Syrians do not eat fish but they worship the images of fish as gods. All the accounts of this constellation’s mythology are disappointingly sketchy.
Bambyce later became known to the Greeks as Hieropolis (meaning ‘sacred city’), now called Manbij. Other classical sources tell us that temples of Atargatis contained fish ponds. The goddess was said to punish those who ate fish by making them ill, but her priests ate fish in a daily ritual.
According to the Greek writer Diodorus Siculus, Derceto deliberately threw herself into a lake at Ascalon in Palestine as a suicide bid in shame for a love affair with a young Syrian, Caystrus, by whom she bore a daughter, Semiramis. Derceto killed her lover and abandoned her child, who was brought up by doves and later became queen of Babylon. In the lake, Derceto was turned into a mermaid, half woman, half fish.

Piscis Austrinus is more noticeable than Pisces in the sky because it contains the first-magnitude star Fomalhaut. This name comes from the Arabic meaning ‘fish’s mouth’, which is where Ptolemy described it as lying. In the sky the fish is shown drinking the water flowing from the jar of Aquarius, a strange thing for a fish to do. Bedouin Arabs visualized Fomalhaut and Achernar (in Eridanus) as a pair of ostriches. The name Fomalhaut is frequently mis-spelt “Formalhaut”.

Piscis Austrinus 1

Prior to the 20th century, the constellation was also known as Piscis Notius, a name used to distinguish it from Pisces and the later introduced Piscis Volans (the flying fish).

It is thought that originally Piscis Austrinus was the only constellation representing a fish, Pisces becoming fish only later. Il semble que la constellation du Poisson austral était déjà connue sous un nom similaire dans l’Égypte antique. C’est donc une constellation ancienne qui fut répertoriée par Ptolémée dans son Almageste. Son nom fait bien sûr pendant à la constellation des Poissons, visible dans l’hémisphère nord.

Triangulum 4

The triangle
مثلثMetallah, Mothallah o Caput Trianguli es el nombre de la estrella α Trianguli (α Tri / 2 Trianguli), que aún siendo la estrella alfa de la constelación de Triangulum, es la segunda más brillante de la misma con una magnitud aparente de +3,42 detrás de β Trianguli. Metallah proviene del árabe y significa "triángulo", mientras que Caput Trianguli viene del latín y significa "cabeza del triángulo".
Unas 13 veces más luminosa que el Sol, Metallah es una subgigante blanco-amarilla de tipo espectral F6IV, es decir, está acabando o ha acabado la fusión del hidrógeno y está empezando la fusión de helio. Su temperatura superficial es de 6350 K, siendo su masa estimada 1,5 veces mayor que la masa solar. Más evolucionada que el Sol, su edad se calcula en sólo 2700 millones de años, algo más de la mitad de la edad del Sol, ya que en las estrellas cuanto mayor es su masa más corta es su vida.
Metallah es una binaria espectroscópica con una compañera muy débil de la que nada se sabe. Debe estar extraordinariamente cerca -quizás en torno a 0,04 UA-, ya que el período orbital es de sólo 1,74 días. Ambas se encuentran a 64 años luz de la Tierra.

β Trianguli est l'étoile la plus brillante de la constellation du Triangle, parfois appelée par le nom traditionnel latin Deltotum ou grec Deltotron, car la constellation du Triangle ressemblait à la lettre grecque majuscule delta (Δ) pour les anciens grecs.
Beta Trianguli est une géante blanche de type A ayant une magnitude apparente de +3,00. Elle est à environ 124 années-lumière de la Terre.

ε Trianguli is a binary star in the constellation Triangulum. It is approximately 370 light years from Earth.
The primary component, Epsilon Trianguli A, is a white A-type main sequence dwarf with an apparent magnitude of +5.50. The 11th magnitude companion, Epsilon Trianguli B, is 4 arcseconds away from the primary.

ستاره دوتایی

Triangulum 3

Triangulum lies just to the north of Aries. In antiquity its distinctive shape of three stars was called Deltoton.
Despite its small size it contains one of Messier's objects, a faint face-on spiral galaxy (see below). Triangulum's stars are even fainter than Aries'.

Double stars:
6 Trianguli [also listed sometimes as iota Tri] is an attractive binary with colour contrast, yellow and blue: 5.3, 6.9; PA 71º and separation 3.9".

Variable stars:
R Trianguli is a long-period variable ranging from 5.4 to 12.6 every 266.9 days. In 2000 the maximum should occur around the first or second week of December.

Triangulum 3

Triangulum is an old constellation and is said to represent the island Sicily, having been honored by Zeus with an eternal position among the stars.

It is in Triangulum that the Italian astronomer, Giuseppe Piazzi, discovered the first asteroid, Ceres, on New Year's Day, 1801.

Triangulum 2

The Triangle

The Triangle and the NileThere is not a lot of mythology associated with The Triangle. The Greeks referred to the constellation as Deltoton, because of its similarity to a Greek capital letter "D", that is, a delta. So the constellation became associated with the Nile Delta and Egypt.
The Triangle and SicilyBecause of its shape, the constellation was also associated with the island of Sicily, which is generally triangular in shape with three well defined promontories on its coastline. The island, according to one story, was portrayed the sky at the wish of the goddess Ceres, who begged this favor from the chief of the Roman gods, Jupiter.

Triangulum 1

Triangulum is a small northern constellation whose three brightest stars, of third and fourth magnitude, form a nearly-isosceles long and narrow triangle.

Since any three points make up the corners of a triangle it is unsurprising, if somewhat unimaginative, to find a triangle among the constellations. Triangulum was known to the Greeks who called it Deltoton, for its shape resembled a capital delta. Aratus described it as an isosceles triangle, having two equal sides and a shorter third side. Eratosthenes said that it represented the Nile river delta. According to Hyginus, some people also saw it as the island of Sicily, which was originally known as Trinacria on account of its three promontories. Trinacria was the home of Ceres, goddess of agriculture. Triangulum contains M33, a galaxy in our Local Group, visible with binoculars.

A smaller triangle, Triangulum Minus, was introduced in 1687 by the Polish astronomer Johannes Hevelius from three stars next to Triangulum. Triangulum Minus was shown on some maps, such as the one reproduced here, but has since fallen into disuse.

jeudi 4 septembre 2008

Centaurus 8

α Cen, also known as Rigil Kentaurus, Rigil Kent, or Toliman, is the brightest star in the southern constellation of Centaurus and an established binary star system, Alpha Centauri AB (α Cen AB). To the unaided eye it appears a single star, whose total visual magnitude identifies it as the third brightest star in the night sky.

β Cen, également connue sous les noms de Hadar et Agena, est la seconde étoile la plus brillante de la constellation du Centaure, et la onzième plus brillante du ciel nocturne.


θ Centauri is a star in the constellation Centaurus. It also has the traditional name Menkent. It is an orange K-type giant with an apparent magnitude of +2.06 and is approximately 60.94 light years from Earth.

γ Centauri is a star in the constellation Centaurus. It also has the traditional name Muhlifain, not to be confused with Muliphein, which is γ Canis Majoris; both names derive from the same Arabic root.
Gamma Centauri is a double star approximately 130 light years from Earth, which consists of two spectral type A0 stars each of apparent magnitude +2.9. For the resolution of the double star system a telescope of at least 15 centimeters in aperture is necessary. They have an orbital period of 83 years.

ε Centauri est une étoile de la constellation du Centaure.
ε Centauri est une géante bleue-blanche de type B avec une magnitude apparente moyenne de +2,29. Elle est classée comme étoile variable de type Beta Cephei et sa luminosité varie entre les magnitudes +2,29 et +2,31 avec une période de 4,07 heures. On lui donne également le nom traditionnel Birdun ou Al Birdhaun (البرﺬﻮﻦ), qui signifie "le cheval de somme" en arabe.

η Centauri est une étoile de la constellation du Centaure.
C'est une étoile en rotation rapide qui effectue une révolution en moins d'un jour. C'est aussi une étoile Be, ce qui signifie qu'elle a des émissions variables dans ses raies spectrales de l'hydrogène. Enfin, elle est également légèrement variable et classée comme une variable de type Gamma Cassiopeiae, avec plusieurs périodes de variabilité. Elle est située à environ 309 années-lumière de la Terre. Eta Centauri est assez grosse pour être à la limite des étoiles qui évoluent en naines blanches et de celles qui finissent en supernovae. Marfikent

ζ Centauri est une étoile de la constellation du Centaure. Elle porte également le nom traditionnel Alnair ou Al-Na'ir al Batn, de l'arabe البطن الناير Al-Na'ir al-baţn[u] signifiant "La brillante de l'estomac".
C'est une étoile binaire spectroscopique avec une période un peu supérieure à 8 jours et une excentricité orbitale estimée à 0,5.

δ Centauri est une étoile de la constellation du Centaure. Elle est parfois appelée par son nom traditionnel chinois 马尾 Ma Wei, qui signifie la queue du cheval.
Elle a une magnitude apparente de +2,60 et est de type B2IVne. Elle est classée comme variable de type Gamma Cassiopeiae et sa luminosité varie entre les magnitudes +2,51 et +2,65.
Cette étoile Be possède le même mouvement propre que les étoiles proches HD 105382 et HD 105383, elles forment donc peut-être un petit amas ou un système d'étoiles triples.

ι Centauri) est une étoile de la constellation du Centaure. Elle porte le nom traditionnel rarement utilisé Alhakim ("La sage"), dérivé du titre arabe Kentaurus al-Hakeem (قنطورس الحكيم), signifiant "Le sage Centaure".
ι Centauri est une étoile blanche de la séquence principale ayant une magnitude apparente de +2,75. Elle est à environ 59 années-lumière de la Terre.

κ Centauri is a binary star in the constellation Centaurus. It is approximately 539 light years from Earth. It also has the traditional name Ke Kwan, from the Mandarin 騎官 qíguān, meaning "the cavalry officer".
The primary component, κ Centauri A, is a blue-white B-type subgiant with an apparent magnitude of +3.13. It is a spectroscopic binary and has a companion located 0.12 arcseconds away.

μ Centauri is a third-magnitude star in the constellation Centaurus. The name Kabkent or Kalb al Kentaurus (Arabic قلب القنطورس) is sometimes applied to this star, as well as to Nu Centauri and Phi Centauri, because they mark what has been traditionally portrayed as the heart of the centaur. Mu Centauri is approximately 527 light years from Earth.
μ Centauri is a blue-white B-type subgiant with a mean apparent magnitude of +3.47. It is classified as a Gamma Cassiopeiae type variable star and its brightness varies from magnitude +2.92 to +3.47.

Proxima Centauri (Latin proximus, proxima, proximum: meaning 'next to' or 'nearest to') is a red dwarf star approximately 4.2 light-years distant in the constellation of Centaurus. It was discovered in 1915 by Robert Innes, the Director of the Union Observatory in South Africa. The star may be part of the Alpha Centauri system, and it is the nearest star to the Sun.
Because of the proximity of this star, its angular diameter can be measured directly, yielding a diameter one-seventh that of the Sun. Proxima Centauri's mass is about an eighth of the Sun's, and its average density is about 40 times that of the Sun. Although it has a very low average luminosity, Proxima Centauri is a flare star that undergoes random increases in brightness because of magnetic activity. The star's magnetic field is created by convection throughout the stellar body, and the resulting flare activity generates a total X-ray emission similar to that produced by the Sun. The mixing of the fuel at Proxima Centauri's core through convection and the star's relatively low energy production rate means that it will be a main-sequence star for another four trillion years, or nearly 300 times the current age of the universe.
Searches for companions orbiting Proxima Centauri have been unsuccessful, although these attempts could only rule out the presence of large companions such as brown dwarfs and supermassive planets. The detection of smaller objects will require the use of new instruments, such as the proposed Space Interferometry Mission. Since Proxima Centauri is a red dwarf and a flare star, whether a planet orbiting this star could support life is disputed. Because of the star's proximity, it has been proposed as a destination for interstellar travel.

Centaurus 7

Centaurus is one of the largest constellations with a clearly discernible asterism: the huge form faces east, with a sword waving menacingly toward Lupus the Wolf on the west.
The constellation has an almost complete list of Bayer stars except for omega, which isn't a star, but a well known globular cluster, NGC 5139 (see below).
The front hooves (or feet, if you wish) are formed by two bright stars: alpha and beta Centauri, known also by the Arabian names of Wazn and Hadar.
Alpha Centauri is best known by the name "Rigil Kentaurus", or the Centaur's foot. This is a triple system, three stars which are the closest to our own Sun.
Alpha1 and alpha2 Centauri form a noted binary (see below). They are 4.393 light years away, and each is approximately the size of the Sun.
The closest star is actually alphaC, known as Proxima Centauri. This is a red dwarf of visual magnitude 11.01 and distance 4.221 light years.
The star has a diameter of about 65,000 km (40,000 miles), or about five times that of the Earth. It is a great distance from the other two (perhaps as far as a sixth of a light year away) and the orbit's period is estimated to be hundreds of thousands of years; Burnham suggests "perhaps ... half a million years".
Proxima Centauri is a flare star and is therefore also known by its variable designation of V645 Centauri. See below for details.
Beta Centauri (Hadar) is the tenth brightest star in the heavens, at 0.61 visual magnitude (which is actually the combined values of its two components). It's 525 light years distant and is a rather difficult visual binary (see below).
Double stars:
Alpha1 and alpha2 Centauri form a wide double with an orbit of 79.92 years: -0.04, 1.2. The 2000.0 values are PA 222º and separation 14.1".
Beta Centauri is a difficult double because of the primary's brightness compared to the companion: 0.58, 3.95; PA 251º, separation 1.3". The orbit has not been calculated, but is thought to be at least several hundred years.
Gamma Centauri is a visual double of two nearly identical stars, with orbit of 84.5 years: 2.9, 2.9. The 2000.0 values are a PA of 347º and separation 1.0".
Eta Centauri is a binary with very faint companion: 2.3, 13; PA 270º, separation 5.6".
Kappa Centauri also has a faint companion: 3.1, 11; PA 82º, separation 3.9"
Variable stars:
AlphaC Centauri (V645 Centauri) is a flare star. That is, its visual magnitude may change rapidly, perhaps taking only several seconds to change its magnitude.
The prototype of this kind of variable is UV Ceti, which has been known to change 3.5 magnitudes within seven seconds!
Since these stars are extremely dim, only the closest ones have been investigated. There are twenty or so such stars within twenty light years of our Sun; they all have an M4.5-M6.5 spectra. Only two have visual magnitudes brighter than 10.
R Centauri is a Mira type variable, 5.3 to 11.8, with 546.2 year period. In 1999 the maximum should arrive in mid-February; the same in 2002.
As the chances of seeing this star at its maximum are therefore not very likely, you might find Burnham's finder's chart (p. 559) of some use.

Centaurus 6

Centaurus is one of several constellations that deal with the Labours of Heracles.
In the Fourth Labour, Heracles' assignment was to bring back a rampaging wild boar that was bringing death and destruction to the inhabitants of the northern part of the Peloponnesian peninsula. On his way, he stops to visit a friend of his, a Centaur named Pholus.
Centaurs were half-men, half-horse, who had all descended from Ixion and Nephele (who was in fact a cloud, shaped by Zeus to resemble his wife Hera).
Centaurs were featured in a number of Greek myths, but by and large remained on the periphery of Greek fable.
As Heracles finishes the sumptuous meal provided by Pholus, he then has the effrontery of opening the Centaurs' private wine cask, meant for them alone. The rest of the Centaurs catch the odour of their wine, wafting across hill and dale, and they become enraged.
Gathering up huge boulders, ripping out trees to use as clubs, and arming themselves with axes, the Centaurs advance on the dinner party.
Pholus takes fright, so the battle is left to Heracles. After repulsing a number of Centaurs single-handedly, Heracles then chases the rest of them to the cave of their king, Cheiron.
Heracles shoots an arrow at one fleeing Centaur (Elatus by name), but it passes through his arm and strikes Cheiron on the knee. You may recall that Heracles' arrows were all dipped in poison, so each was fatal, no matter how slight the wound. Cheiron was a great friend of Heracles, and our hero is devastated. He tries to assist Cheiron, but there is nothing to be done.
Cheiron was immortal, so the poison couldn't kill him, only cause great pain that would last through eternity. He descends to the depths of his cave, his screams of agony echoing throughout the cavernous walls.
Eventually Prometheus takes pity on the long-suffering king of the Centaurs, and offers to take over Cheiron's immortality, if Zeus would agree. Zeus does agree, so Cheiron's agony finally comes to an end, and Zeus places the great king of the Centaurs in the heavens.
Back to the previous battle. The Centaur Pholus looks over the dead and dying and wonders how Heracles' arrows could be so fatal. He plucks one arrow out of a body and looks at it, but it slips through his fingers and strikes him on the foot, killing him instantly.
Heracles hears of the tragedy and returns to bury his friend, at the foot of the mountain that bears his name: Mt Pholoe.
This high plateau region in the interior of the peninsula is just up the road from Olympia. Now called Pholois, this is where the Centaur stories of antiquity originated. It is said that Zeus had held Pholus in very high regard, and therefore also put his likeness in the heavens. Thus the constellation Centaurus represents two Centaurs: Pholus and Cheiron.
The fact that two Centaurs are linked with the constellation is no accident. The earliest extant artifact showing the likeness of a Centaur is a piece of Mycenaean jewellery which shows two centaurs together: half-men, half-horse, facing each other and dancing, similar to satyrs.
These half-men half-horse figures were also transformed at times to half-man half-goat. Many rituals are known to have involved dressing as one of these half-beasts, rituals which may date back to Neolithic times.

Centaurus 5

As the story goes, Hercules had traveled far one day and was very thirsty so he asked a centaur friend, Pholus, to open a jar of the excellent wine kept in his house but belonging jointly to all the centaurs. Pholus did, and when the aroma of this fine wine flowed out over the countryside the other centaurs furiously galloped up to the house and demanded to know how he had dared open the wine without first consulting them. The centaurs began to attack him and Hercules. Pholus fled and left the battle to Hercules. Hercules soon settled matters by killing many of them and driving the rest from the countryside, telling them never to return. Chiron was nearby observing the event, although he has not taken part. Although Hercules knew Chiron, and deeply respected him, he could not recognize his friend from a great distance and accidentally shot him with one of his poisoned arrows. Seeing these events and knowing of his son Hercules' sadness, Zeus gave the good centaur a resting place among the stars as the constellation Sagittarius. Pholus looks over the dead and dying and wonders how Hercules' arrows could be so fatal. He pulled one arrow out of a body and looks at it, but it slips through his fingers and strikes him on the foot, killing him instantly. Hercules heard of the tragedy and returned to bury his friend at the foot of the mountain that bears his name, Mt. Pholoe. This high plateau region in the interior of the Greek peninsula is just up the road from Olympia. The mountain is now called Pholois, this is where the Centaur stories of old originated. It is said that Zeus had held Pholus in very high regard, and therefore also put his likeness in the heavens. The constellation Centaurus represents a centaur, Pholus.

It is unclear which centaur Centaurus is to represent. It is either Chiron or Pholus. Both centaurs are present in the stars, one as Centaurus and the other as Sagittarius.

The centaurs were the half-man, half-horse creatures in Greek mythology. They were rude, untrustworthy, cheating, violent, deceptive and they drank too much. But one centaur named Chiron was different. Chiron was educated by the Sun-god Apollo and Diana, Goddess of the Moon and Wild Animals. Chiron was as kind, gentle, and wise as the other centaurs were mean, fierce, and unthinking. Chiron's many skills and wisdom became so widely known that children of many a famous king were sent to him to be taught all manner of skills. Among his students were the mighty Hercules, the sailor Jason, the warrior Achilles and Aesculapius, who became so skilled at medicine.

Centaurus 4

Beta Centauri

Distance (Light Years) 525 ± 47
Visual Magnitude 0.61
Color (B-V) -0.23

Names For This Star

Hadar is an Arabic word meaning "Ground."
Another name for the star is Agena. According to a note in Allen, this name appears to be a compound of the letter "A" for alpha and "gena" meaning knee. (See the note on p. 154 of the 1963 Dover.) The root of the name would presumably be Latin. However, the only meaning that I have been able to find for the word "gena" is "cheek" rather than "knee".

Description of the Star

Hadar is a blue, hot B1III giant star, maybe 13,000 times as luminous as the sun. There is a companion star lying at an angular separation of 0.871 sec of arc, that is, at a projected distance of 140 AU.
The spectrum of the star seems to indicate further companions revolving with respective periods of 3.7 hours and 352 days.

Theta Centauri

Distance (Light Years) 60.9 ± 0.9
Visual Magnitude 2.06
Color (B-V) 1.01

Names For This Star

The name Menkent for Theta Centauri is not found in Allen, but "Gibson" and "Dolan" offer the translation "The Shoulder of the Centaur" for the name. If Gibson and Dolan are correct then "Menkent" would probably be a mixture of Arabic (Men-, see Menkalinan) and Greek (Kentauros).
Description of the Star

Menkent is a cool, orange K0-IIIb giant having a luminosity about 45 times that of the sun. The spectral type suggests a temperature of around 4500 K, a mass at least 4 times that of the sun, and a diameter at least 16 times larger than the sun.

Rigel kentaurus
Alpha Centauri

Distance (Light Years) 4.395 ± 0.008
Visual Magnitude -0.01
Color (B-V) 0.71

Names For This Star

Rigel Kentaurus derives from the Arabic Al Rijl al Kentaurus, "The Centaur's Foot." This is often shortened to Rigil Kent.
The The Bright Star Catalog lists Toliman as an alternative name for this star.

Description of the Star

The stars of the Rigel Kentaurus system represent the nearest stars to the earth other than the sun.
A Triple Star System

The Rigel Kentaurus system is a triple star system. The A star primary is of spectral type G2V, that is yellow star of the same type as our sun. This star is slightly larger in mass and diameter than the sun, and slightly more luminous.
The B component of the system is separated by about 24 AU from A (that is somewhat greater than the distance between the sun and planet Uranus) and revolves with a period of 79.9 years.

Rigel Kentaurus C is a cool red M5.5Ve main sequence dwarf with a Visual Magnitude of 11.1, corresponding to a luminosity of about 1/17,000 that of the sun. This star is known as Proxima Centauri.

The Nearest Star

Proxima is separated from the other two stars of the system by about 1/6 of a ly. At 4.22 ly from the earth, Proxima is actually the nearest single star to the earth.
See this German site for a nice three-dimensional representation of our nearby neighbor stars.

See this page for more information on the Rigel Kentaurus system.

Rigel Kentaurus B
Alpha2 Centauri

Distance (Light Years) 4.395± 0.008
Visual Magnitude 1.33
Color (B-V) 0.88

Description of the Star

Rigel Kentaurus B is an orange K1V main sequence star having about 46% of the luminosity of the sun. The spectral type implies a temperature of 4750 K, a mass of 70% of that of the sun, and a 83% of the sun's diameter. See this page for more information on this star and the Rigel Kentaurus system.

Centaurus 3

The Centaur

The Brighter Stars of Centaurus


Rigel kentaurus

Rigel Kentaurus B

The Story
The Race of Centaurs

Centaurs were a race half-human and half-horse. They were a quarrelsome ill-bred race who loved to drink. The Archer Sagittarius is also a centaur, but the constellation of Centaurus represents the leader of the centaur race, an individual known as Chiron.

Chiron was quite different from the other centaurs. Actually Chiron became a centaur as the result of an accident; he was conceived when his father Cronus, the chief of the elder gods known as Titans, seduced the sea nymph Philyra. When the pair were surprised by Rhea, Cronus' wife, the guilty husband changed himself into a horse in order to escape the wrath of his wife. As a result of Cronus' transformation the child conceived with Philyra became half-horse itself. This was the centaur Chiron.
The Centaur Teacher

Unlike the other centaurs, Chiron was wise and scholarly. He was excellent teacher at the arts of civilization and of war. Chiron's cave became a training institution for young Greek heroes. It was Chiron who raised both Jason (the hero of the quest for the Golden Fleece) and Achilles (one of the heroes of the Trojan War). And it was Chiron who was the teacher of Asclepius, who appears in the sky as Ophiuchus, the Serpent Wrestler.
The Death of Chiron

Chiron's death came about when the great hero Hercules visited the centaur Pholus. That Pholus offered the hero a cup from the centaurs' vat of wine caused a riot in the centaur tribe. The centaurs attacked Hercules, who forced them back with arrows shot from his great bow. An arrow accidentally pierced the knee of Chiron, who had been trying to make peace. Hercules' arrows were poisoned with the blood of the Hydra. So as a result of the arrow wound, Chiron died and was placed among the stars.

Centaurus 2

Centaurs were mythical beasts, half-man, half-horse. They were a wild and ill-behaved race, particularly when the wine bottle was opened. But one centaur, Chiron, stood out from the rest as being wise and scholarly, and he is the one who is represented by the constellation Centaurus.
Chiron was born of different parents from the other centaurs, which accounts for his difference in character. His father was Cronus, king of the Titans, who one day caught and seduced the sea nymph Philyra. Surprised in the act by his wife Rhea, Cronus turned himself into a horse and galloped away, leaving Philyra to bear a hybrid son.
Chiron grew up to be a skilled teacher of hunting, medicine and music; his cave on Mount Pelion became a veritable academy for young princes in search of a good education. Chiron was so trusted by the gods and heroes of ancient Greece that he was made foster-father to Jason and Achilles; but perhaps his most successful pupil was Asclepius, son of Apollo, who became the greatest of all healers and is commemorated in the constellation Ophiuchus.

For a creature who did so much good during his lifetime, Chiron suffered a tragic death. It arose from a visit paid by Heracles to the centaur Pholus, who entertained him to dinner and offered him wine from the centaurs’ communal jar. When the other centaurs realized their wine was being drunk they burst angrily into the cave, armed with rocks and trees. Heracles repulsed them with a volley of arrows. Some of the centaurs took refuge with Chiron, who had been innocent of the attack, and an arrow of Heracles accidentally struck Chiron in the knee. Heracles, concerned for the good centaur, pulled out the arrow, apologizing profusely, but he already knew that Chiron was doomed. Even Chiron’s best medicine was no match for the poison of the Hydra’s blood in which Heracles had dipped his arrows.
Aching with pain, but unable to die because he was the immortal son of Cronus, Chiron retreated to his cave. Rather than let him suffer endlessly, Zeus agreed that Chiron should transfer his immortality to Prometheus. Thus released, Chiron died and was placed among the stars. Another version of the story simply says that Heracles visited Chiron and that while the two were examining his arrows one accidentally dropped on the centaur’s foot. In the sky, the centaur is depicted as about to sacrifice an animal (the constellation Lupus) on the altar (Ara). Eratosthenes says that this is a sign of Chiron’s virtue.
Centaurus contains the closest star to the Sun, Alpha Centauri, 4.4 light years away. Alpha Centauri is also known as Rigil Kentaurus, from the Arabic meaning ‘centaur’s foot’. To the naked eye it appears as the third-brightest star in the sky, but a small telescope reveals it to be double, consisting of two yellow stars like the Sun. A third, much fainter companion star is called Proxima Centauri because it is slightly closer to us than the other two. Beta Centauri is called Hadar, from an Arabic name signifying one member of a pair of stars. Alpha and Beta Centauri mark the front legs of the centaur, and they act as pointers to Crux, the Southern Cross, which lies under the centaur’s rear quarters. Centaurus also contains the largest and brightest globular star cluster visible from Earth, Omega Centauri.

Centaurus 1

Centaurus, is a bright constellation of the southern hemisphere. One of the largest constellations in the sky. The constellation, when including fainter stars visible to the naked eye, resembles a stick man with the back end of a horse attached. According to Ovid (Fasti v.379), the constellation is Chiron who was a wise centaur (half-man, half-horse) known as a tutor to Jason (the leader of the Argonauts) and tutor to Heracles (a demi-god).
Centaurus is sometimes associated with the constellation Sagitta, an arrow which Centaurus appears to have fired towards the constellation Aquila. As such, together with the constellation Lupus, and the fact that Centaurus is below the ecliptic, this may have formed the basis of the myth of the Erymanthian Boar, one of the Twelve Labours of Heracles.
When the sun is in the sign of Virgo, it sits directly above the constellation Centaurus. The Greeks considered that the centaur Chiron, who was accidentally poisoned and died due to Heracles, while Heracles took a detour from hunting the Erymanthian Boar, was put in the sky as a mark of pity.
The constellation Lupus is next after Centaurus in the sun's transit, and was to the Greeks an arbitrary hunted animal (Therion) — it became a wolf under the Romans. Centaurus appears to have fired an arrow, the constellation Sagitta, towards Aquila, the eagle that tortured Prometheus, thus appearing to release Prometheus from his torment. Centaurus is also under the ecliptic, and thus considered to be in the underworld.

Auriga 8

Theta Aurigae (θ Aur / θ Aurigae) is a binary star in the constellation Auriga. It is approximately 173 light-years from Earth. Rarely used proper names for this star include the Arabic name Maha-Sim or Mahasim, which is a variant of the Arabic name Al-Mi'sam meaning "wrist" that was used to describe both Eta Aurigae and Theta Aurigae [1].
The primary, θ Aurigae A, is a white A-type main sequence dwarf with an apparent magnitude of +2.7. It's companion, θ Aurigae B, is a yellow G-type main sequence dwarf with an apparent magnitude of +7.2. The two stars are separated by 3.5 arcseconds. A third star, the 11th magnitude θ Aurigae C, is 49 arcseconds away, and is an optical companion.
The mean combined apparent magnitude of the system is +2.65 but the primary is an Alpha2 Canum Venaticorum type variable star so the system's brightness varies from magnitude +2.62 to +2.70 with a period of 1.37 days.
It is known as 五車四 (the Fourth Star of the Five Chariots) in Chinese.

ι Aurigae est une étoile de la constellation du Cocher. Dans l'atlas d'Antonín Bečvář, elle porte le nom traditionnel Hassaleh mais elle est aussi appelée Kabdhilinan.
Iota Aurigae est une géante lumineuse orange de type K avec une magnitude apparente de +2,69. Elle est à environ 512 années-lumière de la Terre.
Elle est appelée 五車一 (La première étoile des cinq chariots) en chinois.

ε Aurigae is a star in the constellation Auriga. It also has the traditional names Haldus, Almaaz, or Al Anz. Epsilon Aurigae is an eclipsing binary, whose brightness varies in apparent visual magnitude between +3.0 and +3.8 with a period of about 9,890 days (~27.1 years). It is approximately 2,000 light years distant.
The visible component is a supergiant belonging to the spectral class A8 and is among some of the most luminous stars within 1000 parsecs of the Sun. Its diameter corresponds to about 100 solar diameters. The other (eclipsing) component is not visible.
The most-favored speculation is that it consists of one or two small stars with a ring of opaque dust set nearly edge-on, producing the observed eclipses of 2 years' duration.
The alternate hypothesis is that it is immense, but of low density, and thus semi-transparent.
One of the phenomena exhibited during the eclipse is that the level of obscuration of the A star by the companion diminishes briefly, as though there were a hole in the companion.
This system was an early candidate for containing a black hole but the two models given above are now preferred.
The next eclipse occurs from 2009-2011, and it is hoped that the extensive observations that will likely be carried out may yield further insights into the nature of this system. Finding the star is not difficult; it is the apex of the isosceles triangle formed as the 'nose' of the constellation Auriga, and is visible throughout the winter at northern latitudes, not far from brilliant, yellow Capella.

η Aurigae is a star in the constellation Auriga. Along with ε and ζ Aurigae, it forms an asterism known as "the kids", from which it gets its Latin traditional name Hoedus II.

ζ Aurigae is a star in the constellation Auriga. It also has traditional names Azaleh, Haedus (or Hoedus), Saclateri, Sadatoni.
Zeta Aurigae is an eclipsing binary, which varies from magnitude +3.61 to +3.99 with a period of 972 days.
The main star is a red supergiant, the companion belongs to the spectral class B8. Zeta Aurigae is approximately 790 light-years from Earth.

Auriga 7

Capella (α Aurigae) est l'étoile la plus brillante de la constellation du Cocher, et la sixième étoile la plus brillante du ciel nocturne.
Capella signifie « chevrette » en latin, l'étoile représentant traditionnellement la chèvre que le cocher porte sur le dos, ou bien parfois l'épaule gauche du cocher de la constellation éponyme. Parmi les étoiles les plus brillantes, Capella est l'étoile la plus proche du pôle nord céleste (l'étoile polaire paraît bien pâle en comparaison), et jouit ainsi depuis longtemps d'un rôle très important dans l'ensemble des mythologies.
L'une des principales caractéristiques de Capella est qu'il s'agit d'une étoile double, une binaire spectroscopique, composée de deux géantes jaunes de type spectral G. Chacune de ces deux étoiles est environ 10 fois plus grosse que le Soleil et 50 à 80 fois plus lumineuse. Elles sont séparées l'une de l'autre par 90 millions de kilomètres environ (0,6 ua), avec une période orbitale de 104,02 jours. Capella est également une source de rayons X, probablement due à une activité magnétique de surface sur l'une des composantes du système.
Cette étoile binaire centrale possède également un compagnon beaucoup moins lumineux, qui est lui aussi une étoile double, composé de deux naines rouges de type M, orbitant à environ une année-lumière du couple principal.
Située à seulement 42 années-lumière, Capella est l'une des 100 étoiles les plus proches de la Terre.

β Aurigae, traditionally named Menkalinan (also written as Menkarlina), is a white subgiant star approximately 85 light-years away in the constellation Auriga.

The name Menkalinan is shortened from the Arabic منكب ذي العنان mankib ðī-l-‘inān "shoulder of the rein-holder".
Beta Aurigae is a white star of spectral class A , similar to Vega, Denebola, and Sirius. Beta Aurigae is also a subgiant star, which means it has started to change from burning hydrogen to burning helium, has moved off the main sequence, and is slowly expanding into a giant star like Aldebaran.
Beta Aurigae is actually a ternary (triple) star system. The two brightest components, Beta Aurigae A and B, are both white subgiants. Star B is about the same mass and radius as A. Beta Aurigae A and B form an eclipsing spectroscopic binary; the combined apparent magnitude varies over a period of 3.96004 days between +1.85 and +1.93, as every 47.5 hours one of the stars partially eclipses the other from Earth's perspective. The third star, Beta Aurigae C, is a red dwarf star that is far below naked-eye visibility. It is about 330 AU from the AB pair.
Beta Aurigae is believed to be a stream star member of the Ursa Major Moving Group. It is known as 五車三 (the Third Star of the Five Chariots) in Chinese.

Auriga 6

Is an ancient Northern Hemisphere constellation featuring one of the brightest stars in the heavens: Capella. Auriga is usually pictured as a charioteer; the youth Auriga wields a whip in one hand and holds a goat (Capella) and her two kids in the other.
Capella means "small goat". A previous name of this star was Amalthea, which was the goat that suckled the baby Zeus. There are many ancient stories relating to the star, as every culture in antiquity found a place for this bright companion to Taurus, its closest neighbour. To find Auriga, first locate Orion. Taurus is to the right (west) and just above these two, much higher in the sky, you will see Capella. While this star marks roughly the mid-point of the constellation, north to south, most of the more interesting aspects of the constellation are found to the south of the star, all the way down to El Nath, the second brightest star (gamma Aurigae) which is actually shared with Taurus, and also known as beta Tauri.
Auriga's stars are fairly bright; five are second magnitude or brighter. Alpha Aurigae (Capella) is the sixth brightness star, at a visual magnitude of 0.08. The star is 43.5 light years away, and is about ten times the size of our Sun.
Capella's visual magnitude is really the combined brightnesses of the primary star and a close companion, that revolves every 104 days. There is another companion, much fainter: a red dwarf which is itself a close binary.

Binary stars in Auriga.
Zeta Aurigae is an eclipsing binary; an orange giant primary with a blue companion that orbits every 972 days (2.7 years).
Theta Aurigae is visible in large scopes: 2.6, 7.1; PA 300º and separation 3.6".
Omega Aurigae: 5.0, 8.0; PA 360º, separation 5.4".
14 Aurigae is a multiple double, visible in larger scopes.
The primary is 5.1, with three companions: B (11.1, 352º, 11"), C (7.4, 225º, 15") and D (10.4, 356º, 7.7").

Variable stars in AurigaThere are a half-dozen variable stars in this constellation which are visible in small scopes, most of them of very small variance.
Epsilon Aurigae is an unusual variable which normally maintains a visual magnitude of 2.92 but every 9892 days (27 years) dips down to 3.83.
The next scheduled dip is in the late summer of 2010. The eclipse phase lasts about a year.
R Aurigae is the only Mira-type variable of interest. Normally a rather faint 6.7, every 457.5 days it takes a nose-dive to 13.9. The best time to view this feature is in late November of 2001, when it should be near the transit.

Auriga 5

Auriga is one of the oldest constellations going back to the Babylonian times. It has always been associated with a charioteer.

The Babylonians, Greeks, Arabs, and Chinese have associated Auriga with a chariot.

According to one Greek myth, Hera had a child who was born lame. Disgusted, she threw him out of Heaven to Earth, where he became the famous lame smith, Hephaestus, who fashioned beautiful ornaments and armor for the gods. He is also the smith who came to Orion's rescue after Orion had been blinded. It is said that because he was lame he invented the chariot so that he might get around better.

Son of Helios (the sun god) and Hera (Zeus' wife).

Auriga 4

Alpha Aurigae

Distance (Light Years) 42.2 ± 0.5
Visual Magnitude 0.08
Color (B-V) 0.8

Names For This Star

The name Capella is Latin and means "The Little She-goat."
The star is also known as Alhajoth, an Arabicization of the Greek name of the nymph Aige, who in some versions of the myths of Zeus, is named as one of the nursemaids who tended the infant god on the island of Crete, where he was being hidden from the threat of his monstrous Titan father, Cronos.

Description of the Star

Burnham describes Capella as the sixth brightest star in the sky, and the nearest star to the pole of the stars that are first magnitude or brighter.
A Pair of Giants

Capella is a quadruple system consisting of two giants and two dwarves. The A and B components are a close binary consisting of a yellow G5IIIe giant having 7.2 times the diameter of the sun 2.67 times the mass and a yellow G0III giant having 5.6 times the diameter of the sun and 2.55 times the mass.
The two stars individually have 80 and 50 times the luminosity of the sun. The data of the The Bright Star Catalog seem to indicate that the G5 star is the brighter of the pair.

The spectral types imply temperatures near that of the sun, 5600 K for the G0 star and 5000 K for the G5.

The two stars are separated by about 65 million miles and revolve with a period of 104 days.

The Red Dwarves

The remaining pair of stars in the system are two red dwarves of spectral type M1 and M5 designated as Capella H. These stars appear at Visual Magnitude 10.0 and 13.7 respectively. The separation between the stars is 2 sec of arc, corresponding to a projected distance of 26 A.
The pair of dwarves appear separated from the AB pair by 12 minutes of arc, a projected distance of at least 0.17 ly.

The dwarves are small stars having approximately 40% and 10% of the mass of the sun respectively with 60% and 30% of the sun's diameter. The stars have respective luminosities of about 1.4% of the sun and 0.05%.

Beta Aurigae

Distance (Light Years) 82.1 ± 1.6
Visual Magnitude 1.9
Color (B-V) 0.03

Names For This Star

This star is also known as Menkalina. The star name derives from the Arabic name Al Mankib dhi'l Inan, "The Shoulder of the One Who Holds the Reins," that is, "The Shoulder of the Charioteer."
Description of the Star

The Menkalinan spectrum is characteristic of a white A2IV subgiant star.
Menkalinan is actually a multiple star system. According to Burnham the A and B components are almost identical in size and spectrum and revolve with a period of 3.96 days. The orbit appears almost edge-on to the earth. So one of the two stars eclipses the other twice each revolution.

During an eclipse, about 25% of the diameter of one star is covered by the other, and the brightness of the pair of stars decreases by about 0.09 magnitudes.

According to Burnham, the diameter of each star is about 2.6 times that of the sun. One star is about 2.35 times as massive as the sun, while the other star contains about 2.25 solar masses.

There is a third component to the system, Menkalinan C, of Visual Magnitude 14.1. The C component is separated from A and B by 13 sec of arc which corresponds to a projected distance of 330 AU or more than 8 times the radius of the solar system out to Pluto.