Omega Cassiopeiae
Omega Cassiopeiae (ω Cassiopeiae) is a binary star[2] system in the northern constellation of Cassiopeia. It has a combined apparent visual magnitude of +4.99,[2] which means it is a faint star but visible to the naked eye. Based upon an annual parallax shift of 4.65 mas as seen from Earth,[12] this system is located roughly 730 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.16 due to interstellar dust.[6]
Map of the Bayer-designated stars in Cassiopeia. Omega Cassiopeiae is circled. | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cassiopeia |
| Right ascension | 01h 56m 00.02830s[1] |
| Declination | +68° 41′ 06.8639″[1] |
| Apparent magnitude (V) | +4.99[2] |
| Characteristics | |
| Spectral type | B5 III[3] |
| U−B color index | −0.41[4] |
| B−V color index | −0.09[4] |
| Astrometry | |
| Radial velocity (Rv) | −24.8±4.2[5] km/s |
| Proper motion (μ) | RA: 15.067[1] mas/yr Dec.: −10.313[1] mas/yr |
| Parallax (π) | 4.4802 ± 0.0912 mas[1] |
| Distance | 730 ± 10 ly (223 ± 5 pc) |
| Absolute magnitude (MV) | +0.09[6] |
| Orbit[7] | |
| Period (P) | 69.92 d |
| Eccentricity (e) | 0.30 |
| Periastron epoch (T) | 2420426.02 JD |
| Argument of periastron (ω) (secondary) | 50° |
| Semi-amplitude (K1) (primary) | 29.6 km/s |
| Details | |
| ω Cas A | |
| Mass | 3.5[8] M☉ |
| Radius | 2.7[8] R☉ |
| Luminosity | 178[8] L☉ |
| Surface gravity (log g) | 4.1[8] cgs |
| Temperature | 12,737±100[9] K |
| Rotational velocity (v sin i) | 45.7[10] km/s |
| Age | 232[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a single-lined spectroscopic binary star system with an orbital period of 69.92 days and an eccentricity of 0.30. The visible component has the spectrum of an evolved, B-type giant star with a stellar classification of B5 III.[3] It is a helium-weak star, a type of chemically peculiar star that displays abnormally weak absorption lines of helium for a star of its temperature.[13] Omega Cassiopeiae has an estimated 3.5 times the mass of the Sun and is radiating 178 times the Sun's luminosity from its photosphere at an effective temperature of around 12,737 K.[9]
References
- ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ a b c 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.
- ^ a b van Belle, Gerard T.; von Braun, Kaspar (April 2009), "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars", The Astrophysical Journal, 694 (2): 1085–1098, arXiv:0901.1206, Bibcode:2009ApJ...694.1085V, doi:10.1088/0004-637X/694/2/1085, S2CID 18370219.
- ^ a b Crawford, D. L. (February 1963), "U, b, v, and Hβ Photometry for the Bright B8- and B9-TYPE Stars", Astrophysical Journal, 137: 530, Bibcode:1963ApJ...137..530C, doi:10.1086/147526.
- ^ 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 c Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters, 38 (11): 694–706, arXiv:1606.09028, Bibcode:2012AstL...38..694G, doi:10.1134/S1063773712110035, S2CID 119108982.
- ^ Pourbaix, D.; et al. (2004), "SB9: The Ninth Catalogue of Spectroscopic Binary Orbits", Astronomy & Astrophysics, 424: 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
- ^ a b c d Stassun, Keivan G.; et al. (September 2018), "The TESS Input Catalog and Candidate Target List", The Astronomical Journal, 156: 102, Bibcode:2018AJ....156..102S, doi:10.3847/1538-3881/aad050, ISSN 0004-6256.
- ^ a b Huang, Wenjin; et al. (October 2010), "A Stellar Rotation Census of B Stars: From ZAMS to TAMS", The Astrophysical Journal, 722 (1): 605–619, arXiv:1008.1761, Bibcode:2010ApJ...722..605H, doi:10.1088/0004-637X/722/1/605, S2CID 118532653.
- ^ Moiseeva, A. V.; Romanyuk, I. I.; Semenko, E. A.; Kudryavtsev, D. O.; Yakunin, I. A. (2019). "Fundamental Parameters of CP Stars Observed at the 6-m Telescope. I. Observations in 2009–2011". Astrophysical Bulletin. 74 (1): 62–65. Bibcode:2019AstBu..74...62M. doi:10.1134/S1990341319010061. S2CID 149673065.
- ^ "ome Cas", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2017-08-29.
- ^ 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.
- ^ Renson, P.; Manfroid, J. (May 2009), "Catalogue of Ap, HgMn and Am stars", Astronomy and Astrophysics, 498 (3): 961–966, Bibcode:2009A&A...498..961R, doi:10.1051/0004-6361/200810788.