Tau Librae

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Tau Librae
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Libra
Right ascension 15h 38m 39.38s
Declination −29° 46′ 39.7″
Apparent magnitude (V) +3.66
Absolute magnitude (V) -2.01
Distance 445 ly
(136.503 pc)
Spectral type B2.5V
Other designations
40 Librae, CD -29 11837, HD 139365, HIP 76600, HR 5812, SAO 183649.[1]

Tau Librae (τ Lib, τ Librae) is a Class B2.5, fourth-magnitude star in the constellation Libra. Tau Librae is a stellar system located about 445 light-years from Earth. This star has 3.2 times the radius of the Sun and its outer atmosphere has an effective temperature of 20,911 K.[2]


  1. ^ "HD 139365 -- Star", SIMBAD Astronomical Database, retrieved 2007-01-22 
  2. ^ Underhill, A. B.; et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", Monthly Notices of the Royal Astronomical Society 189: 601–605, Bibcode:1979MNRAS.189..601U, doi:10.1093/mnras/189.3.601