HD 21819

HD 21819
Location of HD 21819 on the map (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Camelopardalis
Right ascension 03h 33m 39.06000s[1]
Declination +54° 58′ 29.4970″[1]
Apparent magnitude (V) 5.97±0.01[2]
Characteristics
Evolutionary stage main sequence star[3]
Spectral type A3 V[4] or A2 Vp[5]
B−V color index +0.11[6]
Astrometry
Radial velocity (Rv)−6.5±1.5[7] km/s
Proper motion (μ) RA: −41.053 mas/yr[1]
Dec.: −0.357 mas/yr[1]
Parallax (π)13.1723 ± 0.0317 mas[1]
Distance247.6 ± 0.6 ly
(75.9 ± 0.2 pc)
Absolute magnitude (MV)+1.62[8]
Details
Mass2.00+0.19
−0.15[9] M☉
Radius2.06±0.10[10] R☉
Luminosity30.6+2.2
−2.0[3] L☉
Surface gravity (log g)4.08[11] cgs
Temperature9,000[12] K
Metallicity [Fe/H]−0.17[11] dex
Rotational velocity (v sin i)160±8[5] km/s
Age737±102[9] Myr
Other designations
AG+54°370, BD+54°693, GC 4229, HD 21819, HIP 16599, HR 1073, SAO 24099, TIC 316848255[13]
Database references
SIMBADdata

HD 21819, also designated as HR 1073, is a solitary star[14] located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.97,[2] making faintly visible to the naked eye under ideal conditions. The object is located relatively close at a distance of 248 light-years based on Gaia DR3 parallax measurements[1] and it is drifting closer with a heliocentric radial velocity of −6.5 km/s.[7] At its current distance, HD 21819's brightness is diminished by an interstellar extinction of 0.17 magnitudes[15] and it has an absolute magnitude of +1.62.[8]

HD 21819 has a stellar classification of A3 V,[4] indicating that it is an ordinary A-type main-sequence star that is generating energy via hydrogen fusion at its core. Abt & Morell (1995) gave a slightly hotter star of A2 Vp,[5] indicating that it is instead an Ap star with weak magnesium lines. It has twice the mass of the Sun[9] and 2.06 times the radius of the Sun.[10] It radiates 30.6 times the luminosity of the Sun[3] from its photosphere at an effective temperature of 9,000 K,[12] giving it a white hue when viewed in the night sky. HD 21819 is metal deficient with an iron abundance of [Fe/H] = −0.17 or 67.6% of the Sun's[11] and it is estimated to be 737 million years old,[9] having completed 55.7% of its main sequence lifetime.[3] Like most hot stars it spins rapidly, having a projected rotational velocity of 160 km/s.[5]

  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 Cite error: The named reference Zorec2012 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Cowley1969 was invoked but never defined (see the help page).
  5. ^ a b c d Cite error: The named reference Abt1995 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Haggkvist1969 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 c d Cite error: The named reference David2015 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Kervella2004 was invoked but never defined (see the help page).
  11. ^ a b c Cite error: The named reference Anders2019 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference Phillip1980 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference DeRosa2013 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Gontcharov2017 was invoked but never defined (see the help page).