Astronomy:7 Cephei
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Short description: Star in the constellation Cepheus
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 21h 27m 46.14144s[1] |
| Declination | +66° 48′ 32.7406″[1] |
| Apparent magnitude (V) | 5.42[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | B7 V[4] |
| B−V color index | −0.099±0.004[2] |
| Astrometry | |
| Radial velocity (Rv) | +3.0±4.2[5] km/s |
| Proper motion (μ) | RA: −11.296[1] mas/yr Dec.: −19.787[1] mas/yr |
| Parallax (π) | 3.9653 ± 0.1148[1] mas |
| Distance | 820 ± 20 ly (252 ± 7 pc) |
| Absolute magnitude (MV) | −1.54[2] |
| Details | |
| Mass | 4.47±0.07[3] M☉ |
| Radius | 3.0[6] R☉ |
| Luminosity | 769+94 −84[3] L☉ |
| Surface gravity (log g) | 3.56[7] cgs |
| Temperature | 12,560+87 −86[3] K |
| Metallicity [Fe/H] | −0.36[7] dex |
| Rotational velocity (v sin i) | 236[3] km/s |
| Age | 38[8] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
7 Cephei is a single[10] star located approximately 820 light years away, in the northern circumpolar constellation of Cepheus. It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.42.[2]
This is a B-type main-sequence star with a stellar classification of B7 V.[4] It is a candidate variable star with an amplitude of 9 micromagnitudes and a period of 0.737±0.002 d.[11] This object has 4.5[3] times the mass of the Sun and about three[6] times the Sun's radius. It is spinning rapidly with a projected rotational velocity of 236 km/s.[3] 7 Cephei is radiating 769[3] times the luminosity of the Sun from its photosphere at an effective temperature of 12,560 K.[3]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Zorec, J. et al. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy and Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode: 2012A&A...537A.120Z.
- ↑ 4.0 4.1 Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement 17: 371, doi:10.1086/190179, Bibcode: 1968ApJS...17..371L
- ↑ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters 32 (11): 759–771, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G.
- ↑ 6.0 6.1 Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367 (2): 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P.
- ↑ 7.0 7.1 Niemczura, E. (June 2003), "Metallicities of the SPB stars from the IUE ultraviolet spectra", Astronomy and Astrophysics 404 (2): 689–700, doi:10.1051/0004-6361:20030546, Bibcode: 2003A&A...404..689N
- ↑ Gullikson, Kevin et al. (2016), "The Close Companion Mass-Ratio Distribution of Intermediate-Mass Stars", The Astronomical Journal 152 (2): 40, doi:10.3847/0004-6256/152/2/40, Bibcode: 2016AJ....152...40G.
- ↑ "7 Cep". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=7+Cep.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Burggraaff, O. et al. (September 2018), "Studying bright variable stars with the Multi-site All-Sky CAmeRA (MASCARA)", Astronomy & Astrophysics 617: 11, doi:10.1051/0004-6361/201833142, A32, Bibcode: 2018A&A...617A..32B.
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