HD 28780
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  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Camelopardalis[1] |
| Right ascension | 04h 36m 24.19802s[2] |
| Declination | +64° 15′ 41.7609″[2] |
| Apparent magnitude (V) | 5.91±0.01[3] |
| Characteristics | |
| Evolutionary stage | main sequence[4] |
| Spectral type | A1 V[5] or A1 III[6] |
| U−B color index | −0.02[7] |
| B−V color index | −0.03[7] |
| Astrometry | |
| Radial velocity (Rv) | −22.6±1.8[8] km/s |
| Proper motion (μ) | RA: −25.398 mas/yr[2] Dec.: −8.119 mas/yr[2] |
| Parallax (π) | 6.6785±0.0412 mas[2] |
| Distance | 488 ± 3 ly (149.7 ± 0.9 pc) |
| Absolute magnitude (MV) | +0.26[1] |
| Details | |
| Mass | 2.48±0.08[9] M☉ |
| Radius | 3.79+0.12 −0.13[10] R☉ |
| Luminosity | 101±2[2] L☉ |
| Surface gravity (log g) | 3.67+0.06 −0.08[10] cgs |
| Temperature | 9,616+134 −132[4] K |
| Metallicity [Fe/H] | −0.21[11] dex |
| Rotational velocity (v sin i) | 41.3±2.0[12] km/s |
| Age | 300+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 | |
| SIMBAD | data |
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,[3] making it faintly viisble to the naked eye under ideal conditions. Gaia DR3 parallax measurements imply a distance of 488 light-years,[2] and it is currently drifting closer with a heliocentric radial velocity of −22.6 km/s.[8] 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.[1]
HD 28780 has a stellar classification of A1 V,[5] 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,[6] 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.[4] 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[2] from its photosphere at an effective temperature of 9,616 K.[4] 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]
