HD 104304

HD 104304 (24 G. Virginis) is a binary star system in the zodiac constellation Virgo. It has a combined apparent visual magnitude of 5.54,^[3] making it visible to the unaided eye under suitable viewing conditions. The system is located at a distance of 41 light-years from the Sun based on parallax measurements.^[2] The primary component has a stellar classification of G8 IV,^[4] which means that this is a subgiant star that has left the main sequence and has begun to evolve into a giant star. The secondary is a faint red dwarf star with a class of M4V.^[5]

HD 104304

Observation data Epoch J2000      Equinox J2000
Constellation	Virgo[1]
Right ascension	12h 00m 44.461s[2]
Declination	−10° 26′ 46.06″[2]
Apparent magnitude (V)	5.54[3]
Characteristics
Spectral type	G8 IV[4] + M4V[5]
U−B color index	+0.43[3]
B−V color index	+0.76[3]
Astrometry
Radial velocity (Rv)	0.14±0.14[2] km/s
Proper motion (μ)	RA: +82.841 mas/yr[2] Dec.: −482.807 mas/yr[2]
Parallax (π)	78.7565±0.1206 mas[2]
Distance	41.41 ± 0.06 ly (12.70 ± 0.02 pc)
Absolute magnitude (MV)	5.15±0.009[6]
Orbit[5]
Period (P)	48.5 yr
Semi-major axis (a)	10.4 AU
Eccentricity (e)	0.29
Inclination (i)	35°
Details
A
Mass	0.98[7] M☉
Radius	1.01[7] R☉
Surface gravity (log g)	4.43[7] cgs
Temperature	5,538[4] K
Metallicity [Fe/H]	0.18[8] dex
Rotational velocity (v sin i)	4.5[9] km/s
Age	8.48[7] Gyr
B
Mass	0.21+0.03 −0.02[5] M☉
Other designations
24 G. Virginis, BD−09°3413, GJ 454, HD 104304, HIP 58576, HR 4587, SAO 157041, LTT 4476[10]
Database references
SIMBAD	data

In 2007, a candidate planet was announced orbiting the primary. This was updated in 2010 when two independent papers announced the discovery of a common proper motion companion red dwarf.^[5][11] It is believed to have a mass of 0.21 M_☉ and spectral type of M4V although the spectrum has not been directly observed. The most likely orbit has a period of 48.5 years and an eccentricity of 0.29.^[5][12] Further measurement will be needed to determine whether the star has a planetary companion, but further companions with masses above 83 M_J and separated by at least 3.9 au can be ruled out.^[5]