Tau4 Serpentis

From Wikipedia
https://en.wikipedia.org/wiki/Tau4_Serpentis
τ4 Serpentis
Observation data
Epoch J2000.0       Equinox J2000.0 ( ICRS)
Constellation Serpens
Right ascension 15h 36m 28.1873s [1]
Declination +15° 06′ 05.128″ [1]
Apparent magnitude (V) 5.89 to 7.07 [2]
Characteristics
Spectral type M5II-III [1]
B−V color index 1.2 [1]
Variable type SRB [2]
Astrometry
Radial velocity (Rv)−26 ± 5 [1] km/s
Proper motion (μ) RA: −3.41 [1]  mas/ yr
Dec.: 9.55 [1]  mas/ yr
Parallax (π)6.27 ± 1.00 [1]  mas
Distanceapprox. 520  ly
(approx. 160  pc)
Absolute magnitude (MV)−0.03 [3]
Details
Luminosity155 [3]  L
Other designations
τ4 Ser, 17 Serpentis, BD+15° 2890, GC 20983, HD 139216, HIP 76423, SAO 101641, PPM 131543 [1]
Database references
SIMBAD data

Tau4 Serpentis, Latinized from τ4 Serpentis, is a M-type bright giant star in the constellation of Serpens, approximately 520 light-years from the Earth. [1] It is classified as a semiregular late-type variable star, and its magnitude varies between +5.89 and +7.07 with a period of approximately 100 days. [2] τ4 is unique among the stars with the Bayer designation τ Serpentis as being the only one with no HR catalog number.

References

  1. ^ a b c d e f g h i j V* tau04 Ser -- Pulsating variable Star, database entry, SIMBAD. Accessed on line September 19, 2008.
  2. ^ a b c 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, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line September 19, 2008.
  3. ^ a b 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.