HD 176051

HD 176051 is a spectroscopic binary star system^[12] approximately 49 light years away from Earth in the constellation Lyra. The pair orbit with a period of 22,423 days (61.4 years) and an eccentricity of 0.25.^[6] Compared to the Sun, they have a somewhat lower proportion of elements more massive than helium.^[10] Their individual masses are estimated at 1.07 and 0.71 solar masses (M_☉).^[3] The system is moving closer to the Sun with a radial velocity of −47^[5] km/s and will reach perihelion in about 269,000 years when it comes within roughly 17 ly (5.1 pc) of the Sun.^[13]

HD 176051

Observation data Epoch J2000      Equinox J2000
Constellation	Lyra[1]
Right ascension	18h 57m 01.60985s[2]
Declination	+32° 54′ 04.5723″[2]
Apparent magnitude (V)	5.20[1]
Characteristics
Spectral type	G0 V + K1 V[3]
U−B color index	+0.029[4]
B−V color index	+0.570[4]
Astrometry
Radial velocity (Rv)	−47.2[5] km/s
Proper motion (μ)	RA: +201.96[2] mas/yr Dec.: −145.46[2] mas/yr
Parallax (π)	67.24±0.37 mas[2]
Distance	48.5 ± 0.3 ly (14.87 ± 0.08 pc)
Absolute magnitude (MV)	4.34[1]
Orbit[6]
Period (P)	22,423 d
Semi-major axis (a)	19.1 AU[7]
Eccentricity (e)	0.25 (0.27[7] or 0.54[8])
Argument of periastron (ω) (secondary)	102°
Semi-amplitude (K1) (primary)	3.51 km/s
Semi-amplitude (K2) (secondary)	0.74 km/s
Details
HD 176051 A
Mass	1.07[3] M☉
Radius	1.06[9] R☉
Luminosity	1.65[1] L☉
Surface gravity (log g)	4.60[10] cgs
Temperature	6,000[10] K
Metallicity [Fe/H]	−0.11[10] dex
Age	8.1[11] Gyr
HD 176051 B
Mass	0.71[3] M☉
Radius	0.81[9] R☉
Other designations
ADS 11871, HR 7162, BD+32°3267, GJ 738, HD 176051, LTT 15567, SAO 67612, HIP 93017[12]
Database references
SIMBAD	AB
	A
	B
Exoplanet Archive	data
ARICNS	data
	data2
Extrasolar Planets Encyclopaedia	data

Planetary system

A planet orbiting one of the stars was discovered through astrometric observations. However, it is not known which stellar component the planet is orbiting around.

The HD 176051 planetary system^[14]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	1.5 ± 0.3 MJ	1.76	1016 ± 40	0	—	—

The planet parameters are given here for the 0.71 M_☉ component B.^[7] But, if instead the planet is orbiting the 1.07 M_☉ component A, its mass is 2.26 M_J with a semimajor axis of 2.02 AU.^[14]

See also

• List of star systems within 45–50 light-years
• Alpha Centauri
• Gamma Cephei