vendredi 19 septembre 2008

Lepus 5


"The Hare", is an ancient constellation found under the feet of Orion, the Hunter. No one seems to know just which culture first saw the constellation as an animal; the Arabs saw it as the "throne of the central one" (i.e. Orion).
Lepus, The Hare is not to be confused with Lupus, The Wolf, which is a spring constellation.
Lepus is often ignored, as Orion is such a dominating constellation. Yet Lepus contains a number of interesting objects. Its Bayer stars are generally third and fourth magnitude.



Double stars:
Beta Leporis is a close binary with faint companion: 2.8, 11; PA 330 degrees, separation 2.5".
Gamma Leporis is a wide binary with slight colour contrast, yellow and orange (although observers vary): 3.7, 6.3; PA 350, separation 96.3".
Kappa Leporis (Struve 661) is a fixed system: 4.5, 7.4; PA 358 degrees, separation 2.6".
h3750 is a fixed binary: 4.7, 8.5; PA 282 degrees, separation 4.2".
h3752 is a fine multiple in the same field as M79.
AB: 5.5, 6.5; PA 97 degrees, separation 3.1". AC: 9; PA 106 degrees, separation 59".
h3780 is a noted multiple system which also goes under the name NGC 2017.
AB: 6.4, 7.9; PA 146 degrees, separation 0.8" AC: 8.5; PA 136 degrees, separation 89.2". AE: 8.4; PA 7, separation 76.1". AF: 8.1; PA 299, separation 28.8". AG: 9.5; PA 49, separation 59.8".



Variable stars:
Mu Leporis is an alpha CV type variable: 2.97 to 3.41 about every two days.
Rho Leporis is an alpha Cygni type variable: 3.83 - 3.90.
R Leporis is a long-period (Mira) variable that ranges from about 6 to about 11.5 every 427.07 days. However sources vary over this figure, and you will find quoted a period ranging from 427 to 440 days. In 2000 the maximum may occur in the last week of December, depending of course on the star's current period.
The star glows with an unusually intense red; it goes by the name of Hind's Crimson Star since John Russell Hind (in 1845) wrote that it resembled "a blood-drop on the background of the sky". Although, unfortunately, as the star brightens it loses much some of its intense colour.
The star is 3.5º NW of mu Leporis. Burnham (p.1094) has a finder's chart. (The star less than two degrees south of R Lep is the close binary b314.)


Deep Sky Objects:
Lepus has one Messier and a tiny star cluster which is actually the half dozen stars which go to make up the multiple h3780.
M79 (NGC 1904) is a small globular cluster about 3.5 degrees SSW of beta Leporis. In the same field, half a degree to the SSW of this cluster, is h3752 (see above).
NGC 2017 is a group of a half dozen stars, all gravitationally bound (h3780, see above). The "cluster" is found seven arc minutes due east of alpha Leporis.

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