Xi Cassiopeiae (ξ Cassiopeiae) is a blue-white hued binary star[6] system in the northern constellation of Cassiopeia. It has an apparent visual magnitude of +4.81[2] and thus is faintly visible to the naked eye. Based upon an annual parallax shift of 2.28 mas as seen from Earth,[1] this system is located roughly 1,400 light years from the Sun. At that distance, the visual magnitude of the system is diminished by an extinction factor of 0.20 due to interstellar dust.[5] It is advancing in the general direction of the Sun with a radial velocity of roughly −10.6 km/s.[4]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cassiopeia |
| Right ascension | 00h 42m 03.89542s[1] |
| Declination | +50° 30′ 45.0915″[1] |
| Apparent magnitude (V) | +4.81[2] |
| Characteristics | |
| Spectral type | B2.5 V[3] |
| U−B color index | −0.60[2] |
| B−V color index | −0.11[2] |
| Astrometry | |
| Radial velocity (Rv) | −10.6±7.4[4] km/s |
| Proper motion (μ) | RA: +12.24±0.38[1] mas/yr Dec.: −6.58±0.32[1] mas/yr |
| Parallax (π) | 2.28 ± 0.51 mas[1] |
| Distance | approx. 1,400 ly (approx. 440 pc) |
| Absolute magnitude (MV) | −0.42[5] |
| Orbit[6] | |
| Period (P) | 940.2 d |
| Eccentricity (e) | 0.4 |
| Periastron epoch (T) | 2441738 JD |
| Argument of periastron (ω) (secondary) | 119° |
| Semi-amplitude (K1) (primary) | 11.90 km/s |
| Details | |
| Mass | 10.1±0.1[7] M☉ |
| Radius | 4.5[8] R☉ |
| Luminosity | 2,873[9] L☉ |
| Surface gravity (log g) | 3.571±0.032[10] cgs |
| Temperature | 15,585±250[10] K |
| Rotational velocity (v sin i) | 139±7[11] km/s |
| Age | 19[10] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a single-lined spectroscopic binary star system with an orbital period of 940.2 days and an eccentricity of 0.4.[6] The visible component has the spectrum of a B-type main-sequence star with a stellar classification of B2.5 V.[3] It has an estimated 10.1[7] times the mass of the Sun and around 4.5[8] times the Sun's radius. At the age of 19[10] million years, it has a high rate of rotation with a projected rotational velocity of about 139 km/s.[11] The star is radiating 2,873[9] times the Sun's luminosity from its photosphere at an effective temperature of around 15,585 K.[10]
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 Crawford, D. L.; et al. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere", The Astronomical Journal, 76: 1058, Bibcode:1971AJ.....76.1058C, doi:10.1086/111220.
- ^ a b Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement, 17: 371, Bibcode:1968ApJS...17..371L, doi:10.1086/190179
- ^ a b 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 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.
- ^ a b c 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 Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
- ^ a b Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy & Astrophysics, 367 (3rd ed.): 521–24, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
- ^ a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
- ^ a b c d e Gullikson, Kevin; et al. (August 2016), "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars", The Astronomical Journal, 152 (2): 13, arXiv:1604.06456, Bibcode:2016AJ....152...40G, doi:10.3847/0004-6256/152/2/40, S2CID 119179065, 40.
- ^ 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.
- ^ "ksi Cas". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-30.