Tau4_Serpentis

Tau<sup>4</sup> Serpentis

Tau4 Serpentis

Star in the constellation Serpens


Tau4 Serpentis, Latinized from τ4 Serpentis, is a variable M-type giant star in the constellation of Serpens, approximately 710 light-years from the Earth.[5]

Quick Facts Constellation, Right ascension ...

With a spectral classification M5IIIa, Tau4 Serpentis is a cool red giant star. The spectrum varies,[4] and some sources classify it between M4IIIe and M6IIIe.[9] Some of its spectral lines show an inverse P Cygni profile,[10] where cold infalling gas on to the star creates redshifted hydrogen absorption lines next to the normal emission lines.[11] It is classified as a semiregular late-type variable, and its magnitude varies between +5.89 and +7.07 with a period of approximately 100 days.[3]

τ4 is unique among the stars with the Bayer designation τ Serpentis as being the only one with no HR catalog number.


References

  1. "ASAS-SN Variable Stars Database". ASAS-SN Variable Stars Database. ASAS-SN. Retrieved 6 January 2022.
  2. tau 4 Ser, database entry, The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars Archived 2017-06-20 at the Wayback Machine, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line September 19, 2008.
  3. Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373. S2CID 123149047.
  4. V* tau04 Ser -- Pulsating variable Star, database entry, SIMBAD. Accessed on line September 19, 2008.
  5. 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.
  6. McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017). "Fundamental parameters and infrared excesses of Tycho-Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433. S2CID 73594365.
  7. Skiff, B. A. (2014). "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)". VizieR On-line Data Catalog: B/Mk. Originally Published in: Lowell Observatory (October 2014). 1. Bibcode:2014yCat....1.2023S.
  8. Kolotilov, E. A.; Russev, R. M. (January 1980). "Inverse P Cyg Profile of Halpha in the Spectrum of the Red Giant HD 139216 = tau4 Ser". Information Bulletin on Variable Stars. 1730: 1. Bibcode:1980IBVS.1730....1K.
  9. Galactic Star and Planet Formation Research Group. "Lecture 7: The Collapse of Cores and Infall" (PDF). Department of Physics and Astronomy, University of Toledo. Retrieved 17 July 2015.

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