  | |
| 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]
