Astronomy:HD 28780
  | |
| Observation data Epoch J2000.0 Equinox (celestial coordinates) | |
|---|---|
| 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[1] mas/yr Dec.: −8.119[1] mas/yr |
| Parallax (π) | 6.6785 ± 0.0412[1] mas |
| Distance | 488 ± 3 ly (149.7 ± 0.9 pc) |
| Absolute magnitude (MV) | +0.26[8] |
| Details | |
| Mass | 2.48±0.08[9] M☉ |
| Radius | 3.79+0.12−0.13[10] R☉ |
| Luminosity | 101±2[1] L☉ |
| Surface gravity (log g) | 3.67+0.06−0.08[10] cgs |
| Temperature | 9,616+134−132[3] 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 | |
| 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,[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]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 Oja, T. (August 1991). "UBV photometry of stars whose positions are accurately known. VI.". Astronomy and Astrophysics Supplement Series 89: 415. ISSN 0365-0138. Bibcode: 1991A&AS...89..415O.
- ↑ 3.0 3.1 3.2 3.3 Zorec, J.; Royer, F. (January 2012). "Rotational velocities of A-type stars IV: Evolution of rotational velocities". Astronomy & Astrophysics 537: A120. doi:10.1051/0004-6361/201117691. ISSN 0004-6361. Bibcode: 2012A&A...537A.120Z.
- ↑ 4.0 4.1 Cowley, A.; Cowley, C.; Jaschek, M.; Jaschek, C. (April 1969). "A study of the bright stars. I. A catalogue of spectral classifications.". The Astronomical Journal 74: 375. doi:10.1086/110819. ISSN 0004-6256. Bibcode: 1969AJ.....74..375C.
- ↑ 5.0 5.1 Abt, Helmut A.; Morrell, Nidia I. (July 1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". The Astrophysical Journal Supplement Series 99: 135. doi:10.1086/192182. ISSN 0067-0049. Bibcode: 1995ApJS...99..135A.
- ↑ 6.0 6.1 Oja, T. (April 1983). "UVB photometry of FK4 and FK4 Supplement stars.". Astronomy and Astrophysics Supplement Series 52: 131–134. ISSN 0365-0138. Bibcode: 1983A&AS...52..131O.
- ↑ 7.0 7.1 Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35,495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. ISSN 1063-7737. Bibcode: 2006AstL...32..759G.
- ↑ 8.0 8.1 Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode: 2012AstL...38..331A.
- ↑ 9.0 9.1 9.2 9.3 Grosbol, P. J. (June 1978). "Space velocities and ages of nearby early-type stars.". Astronomy and Astrophysics Supplement Series 32: 409–421. ISSN 0365-0138. Bibcode: 1978A&AS...32..409G.
- ↑ 10.0 10.1 10.2 Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. Bibcode: 2019AJ....158..138S.
- ↑ 11.0 11.1 Anders, F. et al. (August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy & Astrophysics 628: A94. doi:10.1051/0004-6361/201935765. ISSN 0004-6361. Bibcode: 2019A&A...628A..94A.
- ↑ 12.0 12.1 Ramella, M.; Boehm, C.; Gerbaldi, M.; Faraggiana, R. (January 1989). ""Normal" main sequence A0 stars of low rotational velocity.". Astronomy and Astrophysics 209: 233–243. ISSN 0004-6361. Bibcode: 1989A&A...209..233R.
- ↑ "HD 28780". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+28780.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (11 September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869–879. doi:10.1111/j.1365-2966.2008.13596.x. ISSN 0035-8711. Bibcode: 2008MNRAS.389..869E.
- ↑ Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society 472 (4): 3805–3820. doi:10.1093/mnras/stx2219. ISSN 0035-8711. Bibcode: 2017MNRAS.472.3805G.
 |  |
