Sigma Virginis

Sigma Virginis (σ Vir, σ Virginis) is a star in the zodiac constellation of Virgo. It can be faintly seen with the naked eye with a baseline apparent visual magnitude of 4.86.^[2] Based upon parallax measurements, the distance to this star is roughly 680 light-years.

A light curve for Sigma Virginis, plotted from Hipparcos data^[9]

σ Virginis

Location of σ Virginis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Virgo
Right ascension	13h 17m 36.28327s[1]
Declination	+05° 28′ 11.5221″[1]
Apparent magnitude (V)	4.86[2]
Characteristics
Spectral type	M1 III[3]
U−B color index	+1.86[2]
B−V color index	+1.62[2]
Variable type	suspected[4]
Astrometry
Radial velocity (Rv)	−28.26±0.30[5] km/s
Proper motion (μ)	RA: −6.06[1] mas/yr Dec.: +9.14[1] mas/yr
Parallax (π)	4.83±0.19 mas[1]
Distance	680 ± 30 ly (207 ± 8 pc)
Absolute magnitude (MV)	−1.80[6]
Details
Radius	98[7] R☉
Luminosity	1,610[7] L☉
Surface gravity (log g)	0.42[7] cgs
Temperature	3,690[7] K
Other designations
σ Vir, 60 Virginis, BD+06°2722, FK5 1344, HD 115521, HIP 64852, HR 5015, SAO 119855[8]
Database references
SIMBAD	data

This is an evolved red giant star with a stellar classification of M1 III.^[3] It is a suspected variable star with a brightness that ranges from magnitude +4.77 to +4.86.^[4] This variation has pulsation periods of 23.4, 24.3, 27.9 and 34.1 days.^[3] The effective temperature of the stellar atmosphere is around 3,800 K, and it shines with 1,734 times the luminosity of the Sun.^[7]