Astronomy:Tau1 Serpentis

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Short description: Star in the constellation Serpens


τ1 Serpentis
Tau1SerLightCurve.png
A light curve for Tau1 Serpentis, plotted from Hipparcos data[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Serpens
Right ascension  15h 25m 47.39664s[2]
Declination +15° 25′ 40.9307″[2]
Apparent magnitude (V) 5.16[3] (5.13 to 5.20)[4]
Characteristics
Evolutionary stage AGB[5]
Spectral type M1III[6]
U−B color index +1.95[7]
B−V color index +1.650±0.006[3]
R−I color index +1.04[7]
Astrometry
Radial velocity (Rv)−16.51±0.23[3] km/s
Proper motion (μ) RA: −12.467[2] mas/yr
Dec.: −7.740[2] mas/yr
Parallax (π)3.3030 ± 0.1988[2] mas
Distance990 ± 60 ly
(300 ± 20 pc)
Absolute magnitude (MV)−1.45[3]
Details
Radius99+7
−14
[2] R
Luminosity2,158±149[2] L
Surface gravity (log g)1.07±0.18[8] cgs
Temperature3,954+309
−132
[2] K
Metallicity [Fe/H]0.05±0.06[8] dex
Other designations
τ1 Ser, 9 Serpentis, NSV 7074, BD+15°2858, FK5 570, GC 20740, HD 137471, HIP 75530, HR 5739, SAO 101545[9]
Database references
SIMBADdata

Tau1 Serpentis, Latinized from τ1 Serpentis, is a single[10] star in the Caput (Head) segment of the equatorial constellation of Serpens. It is a red hued star that is dimly visible to the naked eye with an apparent visual magnitude of 5.16.[3] Based upon parallax measurements, this star is located at a distance of approximately 990 light years from the Sun,[2] while it is drifting closer with a radial velocity of −16.5 km/s.[3]

This object is an aging red giant star, currently on the asymptotic giant branch,[5] with a stellar classification of M1III.[6] Having exhausted the supply of hydrogen at its core, it has cooled and expanded until it now has around 99[2] times the girth of the Sun.[2] It is a suspected variable star with a brightness that has been measured varying from magnitude 5.13 down to 5.20.[4] The Hipparcos data for Tau1 Serpentis shows brightness variations with a period of 6.4675 days, and an amplitude of 0.0066 magnitudes.[11] The star is radiating 2,158[2] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,954 K.[2]

References

  1. "/ftp/cats/more/HIP/cdroms/cats". Strasbourg astronomical Data Center. https://cdsarc.cds.unistra.fr/viz-bin/ftp-index?/ftp/cats/more/HIP/cdroms/cats. 
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  4. 4.0 4.1 Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports 61 (1): 80, doi:10.1134/S1063772917010085, Bibcode2017ARep...61...80S. 
  5. 5.0 5.1 Eggen, Olin J. (July 1992), "Asymptotic giant branch stars near the sun", Astronomical Journal 104 (1): 275–313, doi:10.1086/116239, Bibcode1992AJ....104..275E. 
  6. 6.0 6.1 Cenarro, A. J. et al. (July 2009), "Mg and TiO spectral features at the near-IR: spectrophotometric index definitions and empirical calibrations", Monthly Notices of the Royal Astronomical Society 396 (4): 1895–1914, doi:10.1111/j.1365-2966.2009.14839.x, Bibcode2009MNRAS.396.1895C. 
  7. 7.0 7.1 Hoffleit, D.; Warren, Jr., W. H., "HR 5739", The Bright Star Catalogue, http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=V/50/catalog&recno=5739, retrieved 2019-10-17. 
  8. 8.0 8.1 Prugniel, P. et al. (2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics 531: A165, doi:10.1051/0004-6361/201116769, Bibcode2011A&A...531A.165P. 
  9. "tau01 Ser". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=tau01+Ser. 
  10. 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, Bibcode2008MNRAS.389..869E. 
  11. Koen, Chris; Eyer, Laurent (March 2002). "New periodic variables from the Hipparcos epoch photometry". Monthly Notices of the Royal Astronomical Society 331 (1): 45–59. doi:10.1046/j.1365-8711.2002.05150.x. Bibcode2002MNRAS.331...45K.