HD 21447
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Camelopardalis |
| Right ascension | 03h 30m 00.18302s[1] |
| Declination | +55° 27′ 06.5158″[1] |
| Apparent magnitude (V) | 5.09[2] |
| Characteristics | |
| Spectral type | A1 Va[3] |
| B−V color index | 0.022±0.015[2] |
| Astrometry | |
| Radial velocity (Rv) | −1.9±0.9[4] km/s |
| Proper motion (μ) | RA: −46.08[1] mas/yr Dec.: −11.07[1] mas/yr |
| Parallax (π) | 16.42 ± 0.29 mas[1] |
| Distance | 199 ± 4 ly (61 ± 1 pc) |
| Absolute magnitude (MV) | 1.17[2] |
| Details | |
| Mass | 2.32[5] M☉ |
| Radius | 1.9[6] R☉ |
| Luminosity | 32.16[2] L☉ |
| Surface gravity (log g) | 4.06[7] cgs |
| Temperature | 10,049±342[7] K |
| Rotational velocity (v sin i) | 182[7] km/s |
| Age | 146[7] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 21447 is a probable binary star[9] system located in the constellation Camelopardalis. The star is also known as HR 1046. It can be viewed with the naked eye, having an apparent visual magnitude of 5.09.[2] Based upon an annual parallax shift of 16.42±0.29 mas,[1] it is located some 199 light years from the Sun. It is a candidate for membership in the Ursa Major Moving Group.[10]
The primary component is A-type main-sequence star with a stellar classification of A1 Va.[3] It is around 146[7] million years old and is spinning with a projected rotational velocity of 182 km/s.[7] The star has an estimated 2.32[5] times the mass of the Sun and about 1.9[6] times the Sun's radius. It is radiating around 32[2] times the Sun's luminosity from its photosphere at an effective temperature of 10,049 K.[7] The companion is visual magnitude 9.4 star at an angular separation of 14.8″.[9]
References[edit]
- ^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ a b c d e f Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b Gray, R. O.; Garrison, R. F. (December 1987), "The Early A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation", Astrophysical Journal Supplement, 65: 581, Bibcode:1987ApJS...65..581G, doi:10.1086/191237.
- ^ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ a b De Rosa, R. J.; et al. (January 2014), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society, 437 (2): 1216–1240, arXiv:1311.7141, Bibcode:2014MNRAS.437.1216D, doi:10.1093/mnras/stt1932, S2CID 88503488.
- ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (Third ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
- ^ a b c d e f g David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
- ^ "HD 21447". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-05-16.
- ^ a b Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ King, Jeremy R.; et al. (2003), "Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group", The Astronomical Journal, 125 (4): 1980, Bibcode:2003AJ....125.1980K, doi:10.1086/368241.
