HR 6902 (also designated V2291 Oph) is a binary system located 790 light years away[2] from the Sun in the Ophiuchus constellation. The system includes an orange bright giant star and a B-type main sequence star, forming an eclipsing binary of Zeta Aurigae type. The system is also surrounded by a warm circumstellar envelope and the spectra show silicon and carbon absorption up to a distance of 3.3 giant radii.[4]

HR 6902

Visible, blue and ultraviolet light curves for an eclipse of V2291 Ophiuchi, adapted from Griffin et al. (1995)[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Ophiuchus
Right ascension	18h 25m 38.799s[2]
Declination	+08° 01′ 55.23″[2]
Apparent magnitude (V)	+5.64[3]
Characteristics
Spectral type	G9IIb / B8V
Variable type	Zeta Aurigae-type
Astrometry
Proper motion (μ)	RA: -4.07 ± 0.54[2] mas/yr Dec.: -6.34 ± 0.31[2] mas/yr
Parallax (π)	4.14 ± 0.41 mas[2]
Distance	790 ± 80 ly (240 ± 20 pc)
Absolute magnitude (MV)	–1.33[3]
Details
Mass	3.86/2.95[4] M☉
Radius	33/3[4] R☉
Luminosity	562/146 L☉
Temperature	4900/11600[4] K
Orbit
Period (P)	1.055[4] yr
Semi-major axis (a)	1.96[4] AU
Eccentricity (e)	0.311[4]
Inclination (i)	87[4]°
Other designations
V2291 Oph, GSC 01023-02454, HD 169690, HD 169689, 2MASS J18253880+0801551, BD+07 3682, FK5 1478, PPM 165790, HIP 90313, SAO 123462
Database references
SIMBAD	data

References