Alpha Librae

Alpha1 Librae [1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Libra
Right ascension 14h 50m 41.26s
Declination -15° 59' 49.5"
Apparent magnitude (V) +5.15
Absolute magnitude (V) +3.28
Distance 77 ly
(23.62 pc)
Spectral type F3V
Other designations
Kiffa Australis, 8 Librae, HR 5530, HD 130819, BD -15 3965, HIP 72603, SAO 158836, FK5 1387, GC 19970
Alpha2 Librae
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Libra
Right ascension 14h 50m 52.78s
Declination -16° 02' 29.8"
Apparent magnitude (V) +2.75
Absolute magnitude (V) +0.88
Distance 77 ly
(23.62 pc)
Spectral type A3IV
Other designations
Zubenelgenubi, Kiffa Australis, Lanx australis, 9 Librae, HR 5531, HD 130841, BD -15 3966, HIP 72622, SAO 158840, FK5 548, NSV 06827, GC 19975

Alpha Librae (α Lib, α Librae) is the second brightest star in the constellation Libra (despite its Bayer designation as alpha). It has the traditional name Zubenelgenubi. The name, from Arabic الزبن الجنوبي (al-zuban al-janūbiyy), means "southern claw" and was coined before Libra was recognized as distinct from Scorpius. The alternate names Kiffa Australis and Elkhiffa Australis, partial Latin translations of Arabic al-kiffah al-janūbiyy, mean "southern pan (of the scales)". Another name used in older astronomy texts, equivalent to "southern scale or pan", was Lanx Australis.[2]

Contents

Description

Alpha Librae is visual binary located approximately 77 light years from the Sun.

Its two stars are separated in the sky by an angular distance of 231" (3'51"). The position angle of the companion is 314 degrees. The brighter of the two is a white star of spectral type A3, with an apparent brightness of 2.8 and an absolute brightness of 1.1, designated Alpha-2 Librae (α2 Lib). Its companion is a type F4 star of apparent brightness 5.2 and absolute brightness 3.5, designated Alpha-1 Librae (α1 Lib).

Viewing


Alpha Librae, on the right, is the westernmost bright star in the constellation Libra, and is very close to the ecliptic.
α1 Lib and α2 Lib on DSS2 sky survey; 1° view
Credit: AAO/STScI/WikiSky

Alpha Librae is close to the ecliptic so it can be easily occulted by the Moon and (very rarely) by planets. The next occultation by a planet will be by Mercury on 10 November 2052.[3]

See also

References

  1. ^ These table provide astronomical data for each of the stellar components of the Alpha Librae system. The data were retrieved from the Simbad Astronomical Database.
  2. ^ Philippe La Hire, "Tabulae Astronomicae" (1727), see star table, page 13.
  3. ^ Peuschel, Marco (2003). "Astronomische Ereignisse der besonderen Art". Retrieved July 10, 2005.

External links

Coordinates: 14h 50m 41.26s, −15° 59′ 49.5″

Stars of Libra
Bayer
Flamsteed
Nearby