HD 218108

HD 218108
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Octans
Right ascension 23h 08m 23.84044s[1]
Declination −79° 28′ 50.4748″[1]
Apparent magnitude (V) 6.11±0.01[2]
Characteristics
Spectral type A6 Vn[3]
U−B color index +0.10[4]
B−V color index +0.14[4]
Astrometry
Radial velocity (Rv)−7±4.4[5] km/s
Proper motion (μ) RA: +93.016 mas/yr[1]
Dec.: −35.907 mas/yr[1]
Parallax (π)13.1893 ± 0.0236 mas[1]
Distance247.3 ± 0.4 ly
(75.8 ± 0.1 pc)
Absolute magnitude (MV)+1.78[6]
Details
Mass1.80[7] M☉
Radius2±0.1[8] R☉
Luminosity15.24[9] L☉
Surface gravity (log g)4.17±0.07[10] cgs
Temperature8,213±244[11] K
Metallicity [Fe/H]−0.01[12] dex
Rotational velocity (v sin i)194±2[13] km/s
Age249[7] Myr
Other designations
79 G. Octantis[14], CPD−80°1064, FK5 3847, GC 32194, HD 218108, HIP 114258, HR 8786, SAO 258105[15]
Database references
SIMBADdata

HD 218108, also known as HR 8786, is a solitary, white hued star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 6.11,[2] making it faintly visible to the naked eye under ideal conditions. Based on parallax measurements from Gaia DR3, the object is estimated to be 247 light years away.[1] It appears to be approaching the Solar System with a fairly constrained radial velocity of −7 km/s.[5] Paunzen et al. (2001) lists it as a λ Boötis star with a weak magnesium line.[16]

HD 218108 has a stellar classification of A6 Vn,[3] indicating that it is an A-type main-sequence star with broad or nebulous absorption lines due to rapid rotation. In 1966, David Stanley Evans gave it a slightly cooler class of A7 Vn.[17] However, Houk and Cowley (1975) give it a classification of A3/4 V, a main sequence star with the characteristics of an A3 and A4 star.[18] Paunzen et al. (2001) gives it a class of A3 V, indicating that it is instead an ordinary A-type main-sequence star.[16]

Nevertheless, it has 1.8 times the mass of the Sun[7] and twice its radius.[8] It radiates 15.24 times the luminosity of the Sun[9] from its photosphere at an effective temperature of 8,213 K. It is estimated to be 249 million years old[7] and is currently spinning with a high projected rotational velocity of 149 km/s.[13] A solar metallicity was calculated for HD 218108.[12]

  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 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 c d Cite error: The named reference David2015 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference McDonald2012 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference AP1999 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Paunzen2006 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference Díaz2011 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. ^ a b Cite error: The named reference Paunzen2001 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference Evans1966 was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference Houk1975 was invoked but never defined (see the help page).