Tau1 Serpentis

For other stars with this Bayer designation, see Tau Serpentis.
τ1 Serpentis

A light curve for Tau1 Serpentis, plotted from Hipparcos data[1]
Observation data
Epoch J2000.0      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 mas[2]
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]

  1. ^ Cite error: The named reference CDS was invoked but never defined (see the help page).
  2. ^ a b c d e f g h i j k l m Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  3. ^ a b c d e f Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference gcvs was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Eggen1992 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Cenarro2009 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference bsc2 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference prugniel2011 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Koen was invoked but never defined (see the help page).