Astronomy:Sigma Ceti

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Short description: F-type star in the constellation Cetus
Sigma Ceti
Observation data
Equinox J2000.0]] (ICRS)
Constellation Cetus
Right ascension  02h 32m 05.22884s[1]
Declination −15° 14′ 40.8278″[1]
Apparent magnitude (V) 4.78[2]
Characteristics
Spectral type F5 V[3] or F4 IV[4]
U−B color index −0.03[2]
B−V color index +0.45[2]
Astrometry
Radial velocity (Rv)−27.5±0.9[5] km/s
Proper motion (μ) RA: −80.21[1] mas/yr
Dec.: −146.29[1] mas/yr
Parallax (π)37.46 ± 0.25[1] mas
Distance87.1 ± 0.6 ly
(26.7 ± 0.2 pc)
Absolute magnitude (MV)+2.68[3]
Details
σ Cet A
Mass1.21[6] M☉
Radius1.5[7] R☉
Luminosity7.6[8] L☉
Surface gravity (log g)4.07±0.07[9] cgs
Temperature6,527±59[9] K
Metallicity [Fe/H]−0.12±0.04[9] dex
Rotational velocity (v sin i)20[3] km/s
Age2.135[6] Gyr
Other designations
σ Cet, 76 Cet, BD−15° 449, FK5 1071, HD 15798, HIP 11783, HR 740, SAO 148445.[10]
Database references
SIMBADdata

Sigma Ceti (σ Ceti) is the Bayer designation for a star in the equatorial constellation of Cetus. With an apparent visual magnitude of 4.78,[2] it can be seen with the naked eye on a dark night. Based upon an annual parallax shift of 37.46 mas,[1] it lies at an estimated distance of 87.1 light years from the Sun. It is a probable astrometric binary star system.[11]

The primary, component A, appears to be a normal F-type main sequence star with a stellar classification of F5 V.[3] However, Malaroda (1975) assigned it a classification of F4 IV,[4] which would suggest it is a more evolved subgiant star. It is estimated to have 121%[6] of the Sun's mass and around 150% of the radius of the Sun.[7] With an age of about 2.1[6] billion years, it is radiating 7.6[8] times the solar luminosity from its outer atmosphere at an effective temperature of 6,527 K.[9]

Name

This star, along with π Cet, ε Cet and ρ Cet, was Al Sufi's Al Sadr al Ḳaiṭos, the Whale's Breast [12]

According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Sadr al Ḳaiṭos were the title for four stars :ρ Cet as Al Sadr al Ḳaiṭos I, this star (σ Cet) as Al Sadr al Ḳaiṭos II, ε Cet as Al Sadr al Ḳaiṭos III and π Cet as Al Sadr al Ḳaiṭos IV[13]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V. 
  2. ↑ 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, Bibcode: 1986EgUBV........0M. 
  3. ↑ 3.0 3.1 3.2 3.3 Takeda, Yoichi et al. (February 2005), "High-Dispersion Spectra Collection of Nearby F--K Stars at Okayama Astrophysical Observatory: A Basis for Spectroscopic Abundance Standards", Publications of the Astronomical Society of Japan 57 (1): 13–25, doi:10.1093/pasj/57.1.13, Bibcode: 2005PASJ...57...13T. 
  4. ↑ 4.0 4.1 Malaroda, S. (August 1975), "Study of the F-type stars. I. MK spectral types", Astronomical Journal 80: 637–641, doi:10.1086/111786, Bibcode: 1975AJ.....80..637M. 
  5. ↑ 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, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D. 
  6. ↑ 6.0 6.1 6.2 6.3 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, doi:10.1088/0004-637X/804/2/146, Bibcode: 2015ApJ...804..146D. 
  7. ↑ 7.0 7.1 Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (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. 
  8. ↑ 8.0 8.1 McDonald, I. et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–57, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M. 
  9. ↑ 9.0 9.1 9.2 9.3 Prugniel, Ph. et al. (July 2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics 531: A165, doi:10.1051/0004-6361/201116769, Bibcode: 2011A&A...531A.165P. 
  10. ↑ "* sig Cet". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+sig+Cet. 
  11. ↑ 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. 
  12. ↑ Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York: Dover Publications Inc.. p. 162. ISBN 978-0-486-21079-7. https://archive.org/details/starnamestheirlo00alle/page/162. Retrieved 2010-12-12. 
  13. ↑ Jack W. Rhoads - Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology; November 15, 1971

External links



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