68 Ophiuchi

68 Ophiuchi is a binary star system in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint star with an apparent visual magnitude of 4.42.^[1] The system is located around 89.69 parsecs (292.5 ly) distant from the Sun, based on parallax,^[2] and is drifting further away with a radial velocity of +6 km/s.^[6]

68 Ophiuchi

Location of 68 Ophiuchi (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Ophiuchus[1]
Right ascension	18h 01m 45.19884s[2]
Declination	+01° 18′ 18.2775″[2]
Apparent magnitude (V)	4.42[1] + 7.48[3]
Characteristics
Spectral type	A2Vn[4]
U−B color index	+0.02[5]
B−V color index	+0.04[5]
Astrometry
Radial velocity (Rv)	+6.00[6] km/s
Proper motion (μ)	RA: +15.93[2] mas/yr Dec.: −13.29[2] mas/yr
Parallax (π)	11.15±0.60 mas[2]
Distance	290 ± 20 ly (90 ± 5 pc)
Absolute magnitude (MV)	−0.34[1]
Orbit[7]
Period (P)	175.74±4.65 yr
Semi-major axis (a)	1.090±0.027″
Eccentricity (e)	0.831±0.035
Inclination (i)	69.5±3.0°
Longitude of the node (Ω)	160.2±1.6°
Periastron epoch (T)	2019.87±1.48
Argument of periastron (ω) (secondary)	78.9±4.7°
Details
68 Oph A
Mass	3.07[8] M☉
Radius	4.5[9] R☉
Luminosity	160[8] L☉
Surface gravity (log g)	3.76[10] cgs
Temperature	9,594[8] K
Metallicity [Fe/H]	−0.14[11] dex
Rotational velocity (v sin i)	201[8] km/s
Other designations
BD+01°3560, CCDM J18018+0118AB, GC 24534, HIP 88290, HR 6723, HD 164577, NSV 10009, SAO 123035, WDS J18018+0118AB
Database references
SIMBAD	data

This is a spectroscopic binary with an orbital period of 177 years and an eccentricity of 0.83.^[7] The brighter member, component A, is an A-type main-sequence star of spectral type A2Vn,^[4] a star that is currently fusing its core hydrogen. The 'n' suffix indicates "nebulous" lines due to rapid rotation. The star is suspected of varying between magnitudes 4.42 and 4.48.^[12] It displays an infrared excess that matches a circumstellar disk of dust orbiting 32.5 AU from the star with a mean temperature of 160 K.^[13] The secondary companion, component B, is of magnitude 7.48.^[3][14]