Upsilon Librae

Upsilon Librae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Libra
Right ascension 15h 37m 01.45020s[1]
Declination −28° 08′ 06.2926″[1]
Apparent magnitude (V) 3.628[2]
Characteristics
Spectral type K3 III[3]
U−B color index +1.586[2]
B−V color index +1.374[2]
Astrometry
Radial velocity (Rv)−24.9±0.7[4] km/s
Proper motion (μ) RA: −12.82[1] mas/yr
Dec.: −4.15[1] mas/yr
Parallax (π)14.58 ± 0.19 mas[1]
Distance224 ± 3 ly
(68.6 ± 0.9 pc)
Absolute magnitude (MV)−0.28[5]
Details[6]
Mass1.67 M☉
Radius31.5[7] R☉
Luminosity309 L☉
Surface gravity (log g)1.58 cgs
Temperature4,135±20 K
Metallicity [Fe/H]−0.02 dex
Age3.14 Gyr
Other designations
υ Lib, 39 Lib, CD−27° 10464, FK5 579, HD 139063, HIP 76470, HR 5794, SAO 183619.[8]
Database references
SIMBADdata

Upsilon Librae (υ Lib, υ Librae) is the Bayer designation for a double star[9] in the zodiac constellation Libra. With an apparent visual magnitude of 3.628,[2] it is visible to the naked eye. The distance to this star, based upon an annual parallax shift of 14.58,[1] is around 224 light years. It has a magnitude 10.8 companion at an angular separation of 2.0 arc seconds along a position angle of 151°, as of 2002.[10]

The brighter component is an evolved K-type giant star with a stellar classification of K3 III.[3] The measured angular diameter, after correction for limb darkening, is 4.27±0.05 mas.[11] At the estimated distance of the star, this yields a physical size of about 31.5 times the radius of the Sun.[7] It has 1.67 times the mass of the Sun and radiates 309 times the solar luminosity from its outer atmosphere at an effective temperature of 4,135 K.[6] The star is about three billion years old.[6]

Upsilon Librae will be the brightest star in the night sky in about 2.3 million years,[12] and will peak in brightness with an apparent magnitude of −0.46, or more than 40 times its present-day brightness.[12]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Celis1975 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1979 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Ryon2009 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Luck2015 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference lang2006 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Mason2014 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Richichi2005 was invoked but never defined (see the help page).
  12. ^ a b Tomkin, Jocelyn (April 1998). "Once and Future Celestial Kings". Sky and Telescope. 95 (4): 59–63. Bibcode:1998S&T....95d..59T. based on computations from HIPPARCOS data. (The calculations exclude stars whose distance or proper motion is uncertain.) PDF[permanent dead link]