Categories
Rho2 Cephei
Topic: Astronomy
From HandWiki - Reading time: 4 min
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 22h 29m 52.97797s[1] |
| Declination | +78° 49′ 27.4320″[1] |
| Apparent magnitude (V) | 5.50[2] |
| Characteristics | |
| Evolutionary stage | main sequence[1][3] |
| Spectral type | A3 V[4] |
| U−B color index | +0.07[2] |
| B−V color index | +0.06[2] |
| Astrometry | |
| Radial velocity (Rv) | −1.25±0.37[1] km/s |
| Proper motion (μ) | RA: +3.543[1] mas/yr Dec.: −20.840[1] mas/yr |
| Parallax (π) | 13.6037 ± 0.0544[1] mas |
| Distance | 239.8 ± 1.0 ly (73.5 ± 0.3 pc) |
| Absolute magnitude (MV) | +1.07[5] |
| Details | |
| Mass | 2.23±0.03[3] M☉ |
| Luminosity | 32[5] L☉ |
| Surface gravity (log g) | 4.2[6] cgs |
| Temperature | 8,511[3] K |
| Rotational velocity (v sin i) | 133[7] km/s |
| Age | 85[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Rho2 Cephei, Latinized from ρ2 Cephei, or simply ρ Cephei, is a solitary[9] star in the northern constellation of Cepheus. With an apparent visual magnitude of 5.50,[2] it is faintly visible to the naked eye, forming an optical pair with Rho1 Cephei. Based upon an annual parallax shift of 13.6 mas as seen from the Earth, it is located about 240 light years from the Sun.
Rho2 Cephei is an A-type main sequence star with a stellar classification of A3 V,[4] estimated to be 85 million years old. It has a high rate of rotation, showing a projected rotational velocity of 133 km/s.[7] The effective temperature of its photosphere is 8,511 K and its bolometric luminosity, the total amount of radiation it emits at all wavelengths, is 32 L☉.
This star has been called by the Arabic name Al Kalb al Rāʽi, the Shepherd's Dog,[10] which is better known (with the spelling Cebalrai) as a name for β Ophiuchi.
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 2.2 2.3 Oja, T. (April 1983), "UBV photometry of FK4 and FK4 supplement stars", Astronomy and Astrophysics Supplement Series 52: 131–134, Bibcode: 1983A&AS...52..131O.
- ↑ 3.0 3.1 3.2 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, Bibcode: 2012A&A...537A.120Z.
- ↑ 4.0 4.1 Cowley, A. et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal 74: 375–406, doi:10.1086/110819, Bibcode: 1969AJ.....74..375C.
- ↑ 5.0 5.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 6.0 6.1 Gullikson, Kevin; Kraus, Adam; Dodson-Robinson, Sarah (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.
- ↑ 7.0 7.1 Royer, F. et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics 463 (2): 671–682, doi:10.1051/0004-6361:20065224, Bibcode: 2007A&A...463..671R.
- ↑ "rho Cep -- Star", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=rho02+Cep, retrieved 2017-05-05.
- ↑ 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.
- ↑ Allen, R. H. (1899), Star Names: Their Lore and Meaning, p. 159, https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Cepheus*.html
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