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Sigma2 Cancri 
Summary
Sigma2 Cancri, Latinized from σ2 Cancri, is the Bayer designation for a solitary,[8] white-hued star in the constellation Cancer. It is faintly visible to the naked eye, with an apparent visual magnitude of +5.44.[2] Based upon an annual parallax shift of 16.79 mas as seen from Earth,[1] this star is located around 194 light years from the Sun.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cancer |
| Right ascension | 08h 56m 56.59711s[1] |
| Declination | +32° 54′ 37.5423″[1] |
| Apparent magnitude (V) | +5.436[2] |
| Characteristics | |
| Spectral type | A7 IV[3] |
| B−V color index | +0.157[2] |
| Astrometry | |
| Radial velocity (Rv) | −26.2±0.7[4] km/s |
| Proper motion (μ) | RA: −53.49[1] mas/yr Dec.: −66.13[1] mas/yr |
| Parallax (π) | 16.79 ± 0.29 mas[1] |
| Distance | 194 ± 3 ly (60 ± 1 pc) |
| Absolute magnitude (MV) | +1.57[5] |
| Details | |
| Mass | 1.79[6] M☉ |
| Luminosity | 21.5[3] L☉ |
| Surface gravity (log g) | 4.17[6] cgs |
| Temperature | 8,309±283[6] K |
| Rotational velocity (v sin i) | 133[3] km/s |
| Age | 441[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
With an estimated age of 441[6] million years, this is an A-type subgiant star with a stellar classification of A7 IV.[3] It is spinning relatively rapidly with a projected rotational velocity of 133 K.[3] The star has an estimated 1.8[6] times the mass of the Sun and is radiating 21.5[3] times the Sun's luminosity from its photosphere at an effective temperature of roughly 8,309 K.[6]
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 Høg, E.; et al. (March 2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy and Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H, doi:10.1888/0333750888/2862.
- ^ a b c d e f Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
- ^ 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.
- ^ 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 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.
- ^ "sig02 Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-12.
{{cite web}}: CS1 maint: postscript (link) - ^ 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.