Astronomy:Sigma Sculptoris

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Short description: Binary star in the constellation Sculptor
Sigma Sculptoris
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An ultraviolet light curve for Sigma Sculptoris, adapted from Manfroid and Renson (1994)[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Sculptor
Right ascension  01h 02m 26.43280s[2]
Declination −31° 33′ 07.2237″[2]
Apparent magnitude (V) +5.54[3]
Characteristics
Spectral type A1/2 IV[4]
U−B color index +0.13[3]
B−V color index +0.06[3]
Astrometry
Radial velocity (Rv)−15.40±0.50[5] km/s
Proper motion (μ) RA: +80.50[2] mas/yr
Dec.: +14.64[2] mas/yr
Parallax (π)14.04 ± 0.32[2] mas
Distance232 ± 5 ly
(71 ± 2 pc)
Absolute magnitude (MV)+1.24[6]
Orbit[7]
Period (P)46.9 days
Semi-major axis (a)0.35 au
Eccentricity (e)0.195
Inclination (i)27° or 135°
Semi-amplitude (K1)
(primary)		10.3 km/s
Details[7]
A
Mass1.95 M☉
Radius2.0 R☉
Luminosity25.7[8] L☉
Surface gravity (log g)4.02±0.14[9] cgs
Temperature8,470 K
Rotational velocity (v sin i)82.1±1.2[10] km/s
Age560 Myr
B
Mass0.72 M☉
Radius0.67 R☉
Temperature4,530 K
Other designations
σ Scl, CD−32°410, HD 6178, HIP 4852, HR 293, SAO 192884[11]
Database references
SIMBADdata

Sigma Sculptoris, Latinized from σ Sculptoris, is a binary star in the southern constellation of Sculptor. It is faintly visible to the naked eye with an apparent visual magnitude of +5.54.[3] Based upon an annual parallax shift of 14.04 mas as seen from Earth,[2] it is located about 232 light years from the Sun.

The main component is a A-type star with a stellar classification of A1/A2 IV,[4] although many modern papers use a spectral class of A2V and describe Sigma Sculptoris as a somewhat evolved main sequence star.[7] It was suspected to be an Ap[12] or Am star,[13] and an Alpha2 Canum Venaticorum variable,[14] but no chemical peculiarity or variability was found in 2018.[13] The star has an estimated 1.95 the mass of the Sun and around two times the Sun's radius.[7] It is spinning with a projected rotational velocity of 82 km/s[10] and is about 560 million years old.[7] Sigma Sculptoris radiates 25.7[8] times the solar luminosity from its photosphere at an effective temperature of 8,470 K.[7]

The secondary is a relatively small star with 72% the mass of the Sun, 5.7 magnitudes fainter than the primary.[7]

The designation Sigma Sculptoris hasn’t always been allocated to this star. It was given this designation by Lacaille when he created Sculptor. When Bode created his own constellation Machina Electrica, he took about half of Sculptor and parts of Fornax, including this star, which he designated Zeta Machinae Electricae. Bode used Sigma Sculptoris for HD 220929 (HR 8914) instead. After Machina Electrica was deemed obsolete by the IAU, the stars were returned to their original constellations.[15]

References

  1. ↑ Manfroid, J.; Renson, P. (January 1994). "Photometric variations of AP stars". Astronomy and Astrophysics 281: 73–89. Bibcode: 1994A&A...281...73M. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 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. 
  3. ↑ 3.0 3.1 3.2 3.3 Westerlund, B. E. (1963). "Three-colour photometry of early-type stars near the galactic poles". Monthly Notices of the Royal Astronomical Society 127 (1): 83. doi:10.1093/mnras/127.1.83. Bibcode: 1963MNRAS.127...83W. 
  4. ↑ 4.0 4.1 Houk, Nancy (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. 3. Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan. Bibcode: 1982mcts.book.....H. 
  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. ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 Waisberg, Idel; Klein, Ygal; Katz, Boaz (April 2024). "Hidden Companions to Intermediate-mass Stars. XVII. Uncovering a 0.72 M⊙, 0.35 au Companion in the Spectroscopic Binary Sigma Sculptoris*" (in en). Research Notes of the AAS 8 (4): 101. doi:10.3847/2515-5172/ad3de9. ISSN 2515-5172. 
  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. ↑ 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. 
  10. ↑ 10.0 10.1 Díaz, C. G. et al. (July 2011). "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum". Astronomy & Astrophysics 531: A143. doi:10.1051/0004-6361/201016386. Bibcode: 2011A&A...531A.143D. 
  11. ↑ "sig Scl -- Variable Star of alpha2 CVn type". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-id?Ident=sig+Scl. Retrieved 2017-04-13. 
  12. ↑ Renson, P.; Manfroid, J. (2009). "Catalogue of Ap, HGMN and Am stars". Astronomy and Astrophysics 498 (3): 961. doi:10.1051/0004-6361/200810788. Bibcode: 2009A&A...498..961R. 
  13. ↑ 13.0 13.1 Janík, Jan; Krtička, Jiří; Mikulášek, Zdeněk; Zverko, Juraj; Pintado, Olga; Paunzen, Ernst; Prvák, Milan; Skalický, Jan et al. (2018). "A Binary Nature of the Marginal CP Star Sigma Sculptoris". Publications of the Astronomical Society of the Pacific 130 (987). doi:10.1088/1538-3873/aab142. Bibcode: 2018PASP..130e4203J. 
  14. ↑ Samus, N. N. et al. (2009). "General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS 1. Bibcode: 2009yCat....102025S. 
  15. ↑ Ian Ridpath. "Sculptor". http://www.ianridpath.com/startales/sculptor.html. 



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