HD 179079

HD 179079 is a star with an exoplanetary companion in the equatorial constellation of Aquila. It has an apparent visual magnitude of approximately 7.96, making it too faint to be readily visible to the naked eye. The distance to this star can be determine using parallax measurements, which yields an estimate of 228 light years. It is drifting further away with a radial velocity of +20 km/s.

HD 179079

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Aquila[1]
Right ascension	19h 11m 09.82858s[2]
Declination	−02° 38′ 18.1881″[2]
Apparent magnitude (V)	7.95[3]
Characteristics
Evolutionary stage	subgiant[2]
Spectral type	G5IV[3]
Apparent magnitude (B)	8.694[1]
Apparent magnitude (J)	6.734±0.021[1]
Apparent magnitude (H)	6.402±0.031[1]
Apparent magnitude (K)	6.311±0.026[1]
B−V color index	0.744±0.013[1]
Astrometry
Radial velocity (Rv)	19.73±0.20[4] km/s
Proper motion (μ)	RA: −134.355[2] mas/yr Dec.: −89.378[2] mas/yr
Parallax (π)	14.3191±0.0253 mas[2]
Distance	227.8 ± 0.4 ly (69.8 ± 0.1 pc)
Absolute magnitude (MV)	3.87[1]
Details
Mass	1.25±0.09[3] M☉
Radius	1.792±0.016[3] R☉
Luminosity	2.41±0.27[5] L☉
Surface gravity (log g)	4.11±0.04[3] cgs
Temperature	5,672±14[6] K
Metallicity [Fe/H]	0.19±0.03[6] dex
Rotational velocity (v sin i)	1.00±0.52[6] km/s
Age	7.88±0.65[6] Gyr
Other designations
BD−02 4881, HD 179079, HIP 94256, SAO 143111, PPM 202620[7]
Database references
SIMBAD	data
Exoplanet Archive	data

This is an evolved G-type subgiant star with a stellar classification of G5IV.^[3] It is nearly 7–8^[6] billion years old and is chromospherically inactive^[5] with a projected rotational velocity of 1 km/s.^[6] The evolutionary track for this star implies a mass slightly higher than the Sun. It is larger in radius than the Sun and has a higher metallicity; the abundance of elements in the star's atmosphere with higher atomic numbers than hydrogen and helium. HD 179079 is radiating about 2.3^[6] times the luminosity of the Sun from its photosphere at an effective temperature of 5,672 K.^[6]

Planetary system

An exoplanet, HD 179079 b, was announced in August 2009 to be orbiting this star. The planet was detected by the radial velocity method, using the HIRES spectrometer at Keck Observatory.^[5]

The HD 179079 planetary system^[8][3]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	≥0.076±0.012 MJ	0.1214+0.0064 −0.0071	14.4808+0.01 −0.0035	0.049±0.087	—	—

See also

• HD 73534
• List of extrasolar planets