Astronomy:Sigma Andromedae

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Short description: Star in the constellation Andromeda
Sigma Andromedae
Andromeda IAU.svg
Red circle.svg
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, Latinized from σ Andromedae, is the Bayer designation for a single[10] star in the northern constellation of Andromeda. It 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 and ρ Andromedae. 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. Bibcode2021A&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, Bibcode1999VeARI..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, Bibcode2012A&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, Bibcode1969AJ.....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, Bibcode1966CoLPL...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, Bibcode2003AJ....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, Bibcode2016ApJ...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, Bibcode2007A&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, Bibcode2008MNRAS.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, Bibcode2008ApJS..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, Bibcode2012AJ....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, Bibcode1910ApJ....32..300L. 
  15. Lehmann, H. et al. (August 1995), "Variability investigations of possible Maia stars", Astronomy and Astrophysics 300: 783, Bibcode1995A&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, Bibcode2009ApJ...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, Bibcode2014ApJS..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