HD 133981

HD 133981
Observation data
Epoch J2000      Equinox J2000
Constellation Apus
Right ascension 15h 12m 33.97907s[1]
Declination −72° 46′ 14.1634″[1]
Apparent magnitude (V) 6.02±0.01[2]
Characteristics
Spectral type B8 IV[3]
U−B color index −0.24[4]
B−V color index 0.00[4]
Astrometry
Radial velocity (Rv)−13.7±1.3[5] km/s
Proper motion (μ) RA: −14.107 mas/yr[1]
Dec.: −16.361 mas/yr[1]
Parallax (π)3.8088 ± 0.0418 mas[1]
Distance856 ± 9 ly
(263 ± 3 pc)
Absolute magnitude (MV)−1.34[6]
Details
Mass3.72+0.09
−0.05[1] M☉
Radius6.35[7] R☉
Luminosity364+15
−14[1] L☉
Surface gravity (log g)3.48[8] cgs
Temperature10,250[9] K
Metallicity [Fe/H]0.00[10] dex
Age202+23
−2[1] Myr
Other designations
25 G. Apodis[11], CD−72°1096, CPD−72°1714, GC 20391, HD 133981, HIP 74421, HR 5628, SAO 257247[12]
Database references
SIMBADdata

HD 133981, also known as HR 5628, is a solitary, bluish-white hued star located in the southern circumpolar constellation of Apus. It has an apparent magnitude of 6.02,[2] allowing it to be faintly visible to the naked eye in ideal conditions. The object is located relatively far at a distance of 856 light years based on parallax measurements from Gaia DR3[1] but is approaching the Solar System with a heliocentric radial velocity of −13.7 km/s.[5]

HD 133981 has a stellar classification of B8 IV,[3] indicating that it is a B-type star that is evolving towards the red giant branch. Houk and Cowley (1975) gave a slightly more evolved class of B8/9 III,[13] instead indicating that it is a giant star. Some evolutionary models show that it is a star just reaching the end of the main sequence.[1] Nevertheless, it has 3.72 times the mass of the Sun[1] and 6.35 times its girth.[7] It radiates 364 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 10,250 K.[9] HD 133981 is said to be 202 million years old.[1]

HD 133981 lies in front of the distant faint galaxy LEDA 54288.[14] A debris disk has been detected around the star. It has 22.5 times the mass of the Earth and an equilibrium temperature of 27 K.[9]

The HD 133981 planetary system
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
circumstellar disc 1,851 AU — —
  1. ^ a b c d e f g h i j k l Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Abt1995 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Anders2022 was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference Liu2014 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Houk1975 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference LEDA was invoked but never defined (see the help page).