HD 120084

HD 120084 is a star with an orbiting exoplanet^[2] in the northern constellation of Ursa Minor. With an apparent magnitude of 5.91,^[2] it is just visible to the naked eye in suburban skies.^[6] The distance to this system is 339 light-years based on parallax measurements, but it is drifting closer to the Sun with a radial velocity of −9 km/s.^[1]

ConstellationUrsa Minor

Right ascension13^h 42^m 39.20162^s[1]

Declination+78° 03′ 51.9800″^[1]

Apparentmagnitude(V)5.91^[2]

Quick facts Observation data Epoch J2000.0 Equinox J2000.0, Constellation ...

HD 120084

Location of HD 120084 (circled in red)
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Ursa Minor
Right ascension	13h 42m 39.20162s[1]
Declination	+78° 03′ 51.9800″[1]
Apparent magnitude (V)	5.91[2]
Characteristics
Evolutionary stage	Red clump[3]
Spectral type	G7III[2]
B−V color index	1.000[2]
Astrometry
Radial velocity (Rv)	−8.97±0.13[1] km/s
Proper motion (μ)	RA: −64.900(31) mas/yr[1] Dec.: 46.164(33) mas/yr[1]
Parallax (π)	9.6277±0.0258 mas[1]
Distance	338.8 ± 0.9 ly (103.9 ± 0.3 pc)
Absolute magnitude (MV)	+0.96[2]
Details
Mass	2.661±0.335[3] M☉
Radius	11.03±0.65[3] R☉
Luminosity	63+8 −7[3] L☉
Surface gravity (log g)	2.779±0.075[3] cgs
Temperature	4,969±40[4] K
Metallicity [Fe/H]	0.12±0.03[4] dex
Rotational velocity (v sin i)	2.44[2] km/s
Other designations
BD+78°466, FK5 3090, HIP 66903, SAO 7876[5]
Database references
SIMBAD	data
Exoplanet Archive	data

Close

The spectrum of this star matches a type of G7III, indicating it is a G-type giant, an evolved star that used up its hydrogen fuel and has expanded.^[2] After undergoing a helium flash, it is now in the red clump stage generating energy through the fusion of helium.^[3] It has 2.7 times the mass of the Sun and a radius about 11 times the radius of the Sun. It radiates 60 times the Sun's luminosity from its photosphere at an effective temperature of around 4,969 K.^[2][4]