HD 4113

HD 4113 is a double star system in the southern constellation of Sculptor. It is too faint to be viewed with the naked eye, having an apparent visual magnitude of 7.88.^[2] The distance to this star, as estimated by parallax measurements, is 137 light years.^[1] It is receding away from the Sun with a radial velocity of +5 km/s.^[1]

HD 4113

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Sculptor
HD 4113 A
Right ascension	00h 43m 12.59559s[1]
Declination	−37° 58′ 57.4777″[1]
Apparent magnitude (V)	7.880±0.013[2]
HD 4113 B
Right ascension	00h 43m 11.89423s[3]
Declination	−37° 58′ 09.1687″[3]
Apparent magnitude (V)	12.70±0.02[2]
Characteristics
Spectral type	G5V and M0–1V[2]
B−V color index	0.716±0.003[2]
Astrometry
HD 4113 A
Radial velocity (Rv)	5.05±0.12[1] km/s
Proper motion (μ)	RA: 49.412±0.016 mas/yr[1] Dec.: −114.290±0.024 mas/yr[1]
Parallax (π)	23.8256±0.0240 mas[1]
Distance	136.9 ± 0.1 ly (41.97 ± 0.04 pc)
Absolute magnitude (MV)	4.780±0.046[2]
HD 4113 B
Radial velocity (Rv)	4.44±0.39[3] km/s
Proper motion (μ)	RA: 53.733±0.022 mas/yr[3] Dec.: −113.983±0.032 mas/yr[3]
Parallax (π)	23.9023±0.0327 mas[3]
Distance	136.5 ± 0.2 ly (41.84 ± 0.06 pc)
Absolute magnitude (MV)	9.600±0.049[2]
Orbit[4]
Companion	HD 4113 C
Period (P)	348.325+21.932 −15.139 yr
Semi-major axis (a)	50.438+2.060 −1.420 AU
Eccentricity (e)	0.648+0.008 −0.007
Inclination (i)	83.456+2.342 −1.269°
Longitude of the node (Ω)	225.686+0.704 −1.486°
Periastron epoch (T)	2324305.035+127045.323 −7894.349
Argument of periastron (ω) (secondary)	249.665+3.552 −4.805°
Semi-amplitude (K1) (primary)	0.263535+0.002058 −0.003037 km/s
Details[5]
A
Mass	1.02+0.02 −0.03 M☉
Radius	1.08+0.02 −0.04[6] R☉
Luminosity	1.085+0.04 −0.03[6] L☉
Surface gravity (log g)	4.31±0.04 cgs
Temperature	5,638±50 K
Metallicity [Fe/H]	0.20±0.04 dex
Rotational velocity (v sin i)	2.324[2] km/s
Age	7.29+1.91 −1.46 or 5.0+1.3 −1.7[2] Gyr
B
Mass	0.55[2] M☉
Surface gravity (log g)	4.76[2] cgs
Temperature	3,833[2] K
C
Mass	51.913+0.604 −0.458[4] MJup
Other designations
CD−38°223, GC 858, HD 4113, HIP 3391, SAO 192693, GSC 03654-02131[7]
Database references
SIMBAD	data
Exoplanet Archive	data

The primary member of this system, component A, is a Sun-like G-type main-sequence star with a stellar classification of G5V.^[2] Estimates of its age are five^[2] to seven^[5] billion years old, and it is spinning with a leisurely projected rotational velocity of 2.3 km/s.^[2] The star is metal rich, with nearly the same mass,^[5] radius, and luminosity^[6] as the Sun.

Orbiting this star is a giant planet and a brown dwarf (HD 4113 C); the latter has been directly imaged. It also has a co-moving stellar companion, designated component B, which is a red dwarf with a class of M0–1V at an angular separation of 43″. This angle is equivalent to a projected separation of 2,000 AU.^[2]

The most recent parameters for HD 4113 C as of 2022 come from a combination of data from radial velocity, astrometry, and imaging, showing that it is about 52 times the mass of Jupiter, and on an eccentric orbit with a semi-major axis of about 50.4 AU and an orbital period of about 348 years.^[4]

Planetary system

On 26 October 2007, Tamuz et al. used the radial velocity method to find a planet with a minimum mass one and half times that of Jupiter orbiting at 1.28 AU away from HD 4113 A. The planet's orbit is highly eccentric.^[8]

The HD 4113 A planetary system^[4]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (years)	Eccentricity	Inclination	Radius
b	≥1.703+0.040 −0.059 MJ	1.280±0.004	1.442+0.0002 −0.0001	0.899+0.004 −0.003	—	—

See also

• HD 156846
• List of extrasolar planets