HD 169904

HD 169904
Location of HD 204904 on the map (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Octans
Right ascension 18h 42m 14.42015s[1]
Declination −81° 48′ 29.2064″[1]
Apparent magnitude (V) 6.26±0.01[2]
Characteristics
Evolutionary stage main sequence star[3]
Spectral type B8 V[4]
U−B color index −0.37[5]
B−V color index −0.13[5]
Variable type suspected[6]
Astrometry
Radial velocity (Rv)−6.0±4.3[7] km/s
Proper motion (μ) RA: +13.838 mas/yr[1]
Dec.: −16.605 mas/yr[1]
Parallax (π)6.7598 ± 0.0413 mas[1]
Distance482 ± 3 ly
(147.9 ± 0.9 pc)
Absolute magnitude (MV)+0.19[8]
Details
Mass3.25±0.06[3] M☉
Radius2.42±0.12[9] R☉
Luminosity141+14
−13[3] L☉
Surface gravity (log g)4.20[10] cgs
Temperature13,622[11] K
Metallicity [Fe/H]−0.18[12] dex
Rotational velocity (v sin i)123[13] km/s
Other designations
35 G. Octantis[14], NSV 24510, CD−81°693, CPD−81°813, GC 25366, HD 169904, HIP 91723, HR 6912, SAO 258804, TIC 351920521[15]
Database references
SIMBADdata

HD 169904 (HR 6912; 35 G. Octantis) is a solitary star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 6.26,[2] placing it near the limit for naked eye visibility, even under ideal conditions. Gaia DR3 parallax measurements imply a distance of 482 light-years[1] and it is currently drifting closer with a somewhat constrained radial velocity of −6.0 km/s.[7] At its current distance, HD 169904's brightness is diminished by 0.24 magnitudes due to interstellar extinction[16] and it has an absolute magnitude of +0.19.[8]

HD 169904 has a stellar classification of B8 V,[4] indicating that it is an ordinary B-type main-sequence star that is generating energy via hydrogen fusion at its core. It has 3.25 times the mass of the Sun[3] and 2.42 times the radius of the Sun.[9] It radiates 141 times the luminosity of the Sun[3] from its photosphere at an effective temperature of 13,622 K,[11] giving it a blue-white hue when viewed in the night sky. HD 169904 is metal deficient with an iron abundance of [Fe/H] = −0.18 or 66.1% of the Sun's,[12] and it spins rapidly with a projected rotational velocity of 123 km/s.[13] HD 169904 is estimated to have completed 47.5% of its main sequence lifetime.[3]

The object was listed as a suspected variable star based on photometric observations,[6] but subsequent observations have not confirmed this.[17]

  1. ^ a b c d e 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 c d e f Cite error: The named reference Zorec2012 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Houk1975 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Gronbech1976 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Kervella2004 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference McDonald2017 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Phillip1980 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference Anders2022 was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference Levato2004 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Gontcharov2017 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference Samus2004 was invoked but never defined (see the help page).