HD 28780

HD 28780
Location of HD 28780 on the map (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Camelopardalis
Right ascension 04h 36m 24.19802s[1]
Declination +64° 15′ 41.7609″[1]
Apparent magnitude (V) 5.91±0.01[2]
Characteristics
Evolutionary stage main sequence star[3]
Spectral type A1 V[4] or A1 III[5]
U−B color index −0.02[6]
B−V color index −0.03[6]
Astrometry
Radial velocity (Rv)−22.6±1.8[7] km/s
Proper motion (μ) RA: −25.398 mas/yr[1]
Dec.: −8.119 mas/yr[1]
Parallax (π)6.6785 ± 0.0412 mas[1]
Distance488 ± 3 ly
(149.7 ± 0.9 pc)
Absolute magnitude (MV)+0.26[8]
Details
Mass2.48±0.08[9] M☉
Radius3.79+0.12
−0.13[10] R☉
Luminosity101±2[1] L☉
Surface gravity (log g)3.67+0.06
−0.08[10] cgs
Temperature9,616+134
−132[3] K
Metallicity [Fe/H]−0.21[11] dex
Rotational velocity (v sin i)41.3±2.0[12] km/s
Age300+21
−19[9] Myr
Other designations
AG+64°277, BD+63°515, FK5 2336, GC 5574, HD 28780, HIP 21452, HR 1440, SAO 13196[13]
Database references
SIMBADdata

HD 28780, also known as HR 1440, is a solitary white-hued star[14] located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.91,[2] making it faintly viisble to the naked eye under ideal conditions. Gaia DR3 parallax measurements imply a distance of 488 light-years,[1] and it is currently drifting closer with a heliocentric radial velocity of −22.6 km/s.[7] At its current distance, HD 28780's brightness is diminished by 0.33 magnitudes due to interstellar extinction[15] and it has an absolute magnitude of +0.26.[8]

HD 28780 has a stellar classification of A1 V,[4] indicating that it is an ordinary A-type main-sequence star that is generating energy via hydrogen fusion at its core. However, Abt & Morell (1995) gave a classification of A1 III,[5] indicating that it is an evolved A-type giant star that has exhausted hydrogen fusion at its core. At the age of 300 million years,[9] HD 28780 has completed 80.2% of its main sequence lifetime.[3] It has 2.48 times the mass of the Sun[9] and a slightly enlarged radius 3.79 times larger than the Sun's.[10] The star radiates 101 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 9,616 K.[3] HD 28780 is metal deficient with an iron abundance 61.7% that of the Sun's ([Fe/H] = −0.21)[11] and unlike most hot stars, it spins modestly with a projected rotational velocity of 41.3 km/s.[12]

  1. ^ a b c d e f g Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Oja1991 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 Cite error: The named reference Abt1995 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Oja1983 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 Grosbol1978 was invoked but never defined (see the help page).
  10. ^ a b c Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Anders2019 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference Ramella1989 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 Eggleton2008 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).