Tau1 Serpentis

τ¹ Serpentis

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Serpens
Right ascension	15^h 25^m 47.3967^s[1]
Declination	+15° 25′ 40.930″[1]
Apparent magnitude (V)	5.13 to 5.20[2]
Characteristics
Spectral type	M1III[1]
U−B color index	+1.95[3]
B−V color index	+1.66[3]
R−I color index	+1.04[3]
Astrometry
Radial velocity (Rv)	−19.8 ± 0.9[1] km/s
Proper motion (μ)	RA: −14.02[1] mas/yr Dec.: −7.51[1] mas/yr
Parallax (π)	3.55 ± 0.76[1] mas
Distance	approx. 900 ly (approx. 280 pc)
Absolute magnitude (MV)	−2.1[4]
Details
Radius	54[5] R☉
Other designations
τ^1 Ser, Tau^1 Serpentis, Tau^1 Ser, 9 Serpentis, 9 Ser, BD+15 2858, FK5 570, GC 20740, HD 137471, HIP 75530, HR 5739, PPM 131392, SAO 101545.[1]
Database references
SIMBAD	data

Tau¹ Serpentis (Tau¹ Ser, τ¹ Serpentis, τ¹ Ser) is an M-type giant star in the constellation of Serpens, approximately 900 light-years from Earth.^[1] It has an apparent visual magnitude which varies between 5.13 and 5.20.^[2]

References

1. NSV 7074 -- Variable Star, database entry, SIMBAD. Accessed on line September 19, 2008.
2. NSV 7074, database entry, New Catalogue of Suspected Variable Stars, the improved version, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line September 19, 2008.
3. HR 5739, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line September 19, 2008.
4. From apparent magnitude and parallax.
5. HD 137471, database entry, Catalog of Apparent Diameters and Absolute Radii of Stars (CADARS), 3rd edition, L. E. Pasinetti-Fracassini, L. Pastori, S. Covino, and A. Pozzi, CDS ID II/224. Accessed on line September 19, 2008.