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HD 171028
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Ophiuchus
Right ascension	18h 32m 15.4933s
Declination	06° 56′ 44.6858″
Apparent magnitude (V)	8.301
Characteristics
Spectral type	G0
B−V color index	0.61
Astrometry
Radial velocity (Rv)	+13.48±0.28 km/s
Proper motion (μ)	RA: −42.869±0.084 mas/yr ; Dec.: −14.705±0.077 mas/yr
Parallax (π)	8.9274 ± 0.0497 mas
Distance	365 ± 2 ly ; (112.0 ± 0.6 pc)
Details
Mass	1.01±0.06 M☉
Radius	2.42+0.01; −0.03 R☉
Luminosity	5.406+0.042; −0.041 L☉
Surface gravity (log g)	3.84±0.03 cgs
Temperature	5,671±16 K
Metallicity [Fe/H]	−0.48±0.01 dex
Rotational velocity (v sin i)	2.3 km/s
Age	4.890±0.229 Gyr
Other designations
	BD+06 3833, TYC 458-1450-1, 2MASS J18321548+0656446
Database references
SIMBAD	data

HD 171028 is a star with an exoplanet companion in the equatorial constellation of Ophiuchus. With an apparent visual magnitude of 8.3,^[2] it is too faint to be readily visible with the naked eye. Unlike most planet-harboring stars, it does not have a Hipparcos number. The star is located at a distance of approximately 365 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +13.5 km/s.^[1]

This is a yellow-hued G-type star of unknown luminosity class with a stellar classification of G0.^[3] It is a metal-poor star belonging to the thin disk population.^[6] HD 171028 is estimated to be nearly five billion years old and is spinning with a projected rotational velocity of 2.3 km/s.^[3] It has the same mass as the Sun, but the radius is 2.4 times larger. The star is radiating 5.4^[1] times the luminosity of the Sun from its photosphere at an effective temperature of 5,671 K.^[2]

In the summer of 2007, a Jovian planetary companion was discovered by the HARPS planet search program using the radial velocity method.^[3] This object is orbiting at a distance of 1.32 AU from the host star with a period of 1.5 years and an eccentricity (ovalness) of 0.59. Since the inclination of the orbit is unknown, only a minimum mass can be determined. This planet has at least double the mass of Jupiter.^[7]