Astronomy:Sigma Andromedae

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Short description: Star in the constellation Andromeda
Sigma Andromedae
Location of σ Andromedae (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Andromeda
Right ascension  00h 18m 19.65737s[1]
Declination +36° 47′ 06.8085″[1]
Apparent magnitude (V) +4.51[2]
Characteristics
Evolutionary stage main sequence[3]
Spectral type A2 V[4]
U−B color index +0.07[5]
B−V color index +0.05[5]
Astrometry
Radial velocity (Rv)–8.0[2] km/s
Proper motion (μ) RA: −65.212(153)[1] mas/yr
Dec.: −42.221(124)[1] mas/yr
Parallax (π)23.2542 ± 0.1809[1] mas
Distance140 ± 1 ly
(43.0 ± 0.3 pc)
Absolute magnitude (MV)1.33[6]
Details
Mass2.12±0.01[3] M☉
Radius2.13[7] R☉
Luminosity21.23[7] L☉
Surface gravity (log g)4.02[6] cgs
Temperature8,929[6] K
Rotational velocity (v sin i)123[8] km/s
Age450[7] Myr
Other designations
σ And, 25 Andromedae, BD+35°44, FK5 1005, HD 1404, HIP 1473, HR 68, SAO 53798, PPM 65183[9]
Database references
SIMBADdata

Sigma Andromedae is a single[10] star in the northern constellation of Andromeda. Its Bayer designation is Latinized from σ Andromedae, and abbreviated Sig And or σ And, respectively. The star has an apparent visual magnitude of +4.5,[2] which is bright enough to be seen with the naked eye from most locations. Parallax measurements made during the Gaia mission place it at a distance of about 140 light-years (43 parsecs).[1] The magnitude of the star is diminished by 0.08 from extinction caused by intervening gas and dust.[11] It is drifting closer to the Sun with a radial velocity of –8 km/s.[2]

This star has a stellar classification of A2 V,[4] which matches the spectrum of an A-type main sequence star. It is about 450 million years old[12] and is spinning rapidly with a projected rotational velocity of 123 km/s.[8] The star has 2.12[3] times the mass of the Sun and 2.13[7] times the Sun's girth. It is radiating 21[7] times the luminosity of the Sun from its photosphere at an effective temperature of 8,929 K,[6] giving it the white-hued glow of an A-type star.[13]

In the past, radial velocity variations have been reported,[14] but this remains unconfirmed.[10] The star does not show any significant photometric variations and is used as an ubvy standard star.[15] A debris disk of warm dust around this star has been detected by Spitzer Space Telescope.[16][17] A model fit to the data yields an orbital distance of 20.3 astronomical unit|AU from the host star with a mean temperature of 132.9 K.[7]

Sigma Andromedae is a candidate for membership in the stream of stars associated with the Ursa Major Moving Group. This is a set of stars that share a common motion through space, which suggests they originated together.[6]

Naming

In Chinese, 天廄 (Tiān Jiù), meaning Celestial Stable, refers to an asterism consisting of σ Andromedae, θ Andromedae, ρ Andromedae and seven other fainter, unidentified stars. Consequently, the Chinese name for σ Andromedae itself is 天廄三 (Tiān Jiù sān, English: the Third Star of Celestial Stable.)[18]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 Wielen, R. et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg (Astronomisches Rechen-Institut Heidelberg) 35 (35): 1, Bibcode: 1999VeARI..35....1W. 
  3. ↑ 3.0 3.1 3.2 Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode: 2012A&A...537A.120Z. 
  4. ↑ 4.0 4.1 Cowley, A. et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal 74: 375–406, doi:10.1086/110819, Bibcode: 1969AJ.....74..375C. 
  5. ↑ 5.0 5.1 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J. 
  6. ↑ 6.0 6.1 6.2 6.3 6.4 King, Jeremy R. et al. (April 2003), "Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group", The Astronomical Journal 125 (4): 1980–2017, doi:10.1086/368241, Bibcode: 2003AJ....125.1980K. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 Gáspár, András et al. (August 2016), "The Correlation between Metallicity and Debris Disk Mass", The Astrophysical Journal 826 (2): 14, doi:10.3847/0004-637X/826/2/171, 171, Bibcode: 2016ApJ...826..171G. 
  8. ↑ 8.0 8.1 Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics 463 (2): 671–682, doi:10.1051/0004-6361:20065224, Bibcode: 2007A&A...463..671R. 
  9. ↑ "sig And". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=sig+And. 
  10. ↑ 10.0 10.1 Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E. 
  11. ↑ van Belle, G. T. et al. (May 2008), "The Palomar Testbed Interferometer Calibrator Catalog", The Astrophysical Journal Supplement Series 176 (1): 276–292, doi:10.1086/526548, Bibcode: 2008ApJS..176..276V. 
  12. ↑ Vican, Laura (June 2012), "Age Determination for 346 Nearby Stars in the Herschel DEBRIS Survey", The Astronomical Journal 143 (6): 135, doi:10.1088/0004-6256/143/6/135, Bibcode: 2012AJ....143..135V. 
  13. ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-06-24. 
  14. ↑ Lee, O. J. (November 1910), "Measures on nineteen new spectroscopic binaries", Astrophysical Journal 32: 300–308, doi:10.1086/141806, Bibcode: 1910ApJ....32..300L. 
  15. ↑ Lehmann, H. et al. (August 1995), "Variability investigations of possible Maia stars", Astronomy and Astrophysics 300: 783, Bibcode: 1995A&A...300..783L 
  16. ↑ Morales, F.Y. et al. (July 2009), "Spitzer Mid-IR Spectra of Dust Debris Around A and Late B Type Stars: Asteroid Belt Analogs and Power-Law Dust Distributions", The Astrophysical Journal 699 (2): 1067–1086, doi:10.1088/0004-637X/699/2/1067, Bibcode: 2009ApJ...699.1067M, https://authors.library.caltech.edu/15348/1/Morales2009p4714Astrophys_J.pdf 
  17. ↑ Patel, Rahul I. et al. (2014), "A Sensitive Identification of Warm Debris Disks in the Solar Neighborhood Through Precise Calibration of Saturated Wise Photometry", The Astrophysical Journal Supplement Series 212 (1): 10, doi:10.1088/0067-0049/212/1/10, Bibcode: 2014ApJS..212...10P. 
  18. ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 18 日



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