HD 142022

HD 142022 is a binary star^[8] system located in the southernmost constellation of Octans. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 7.70.^[2] The distance to this system is 112 light-years (34 parsecs) based on parallax, but it is drifting closer to the Sun with a radial velocity of −10 km/s.^[1]

HD 142022

Observation data Epoch J2000      Equinox J2000
Constellation	Octans
Right ascension	16h 10m 15.02895s[1]
Declination	−84° 13′ 53.8108″[1]
Apparent magnitude (V)	7.70[2] + 11.19[3]
Characteristics
Spectral type	G9IV-V[4] + M1V[3]
B−V color index	0.79±0.01[2]
Astrometry
Radial velocity (Rv)	−9.96±0.13[1] km/s
Proper motion (μ)	RA: −337.270 mas/yr[1] Dec.: −31.386 mas/yr[1]
Parallax (π)	29.1991±0.0172 mas[1]
Distance	111.70 ± 0.07 ly (34.25 ± 0.02 pc)
Absolute magnitude (MV)	5.02[2]
Details[5][3]
A
Mass	0.972+0.036 −0.029 M☉
Radius	1.028+0.011 −0.012 R☉
Luminosity	0.886±0.001[6] L☉
Surface gravity (log g)	4.386±0.251 cgs
Temperature	5,516±31 K
Metallicity [Fe/H]	0.24±0.073 dex
Rotational velocity (v sin i)	2.048±0.214 km/s
Age	7.667+1.704 −1.764 Gyr
B
Mass	0.60±0.07 M☉
Radius	0.56±0.05 R☉
Luminosity	0.063±0.014 L☉
Temperature	3,892±95 K
Other designations
CD−83°202, GC 21507, GJ 606.1, GJ 9536, HD 142022, HIP 79242, SAO 258738, LTT 6382, GCRV 65757[7]
Database references
SIMBAD	data

The primary, designated component A, is an old,^[8] Population I G-type star with a stellar classification of G9IV-V,^[4] showing a spectrum with mixed traits of a main sequence and a subgiant star. It is an estimated 7.6 billion years old and is spinning with a projected rotational velocity of 2 km/s. The star has similar mass and dimensions as the Sun, but has a 55% higher metallicity.^[5] It is radiating 89%^[6] of the luminosity of the Sun from its photosphere at an effective temperature of 5516 K.^[5]

The magnitude 11.19^[3] companion has the designation LTT 6384 and appears gravitationally bound to the primary. The pair have an angular separation of 22 arcseconds, which corresponds to a projected separation of ~820 AU. The estimated semimajor axis of their orbit is 1,033 AU.^[8] The secondary is a red dwarf star with a stellar classification of M1V.^[3]

The primary star has a single known planetary companion, HD 142022 Ab, discovered in 2005.^[8] In 2023, the inclination and true mass of HD 142022 Ab were determined via astrometry.^[9]

The HD 142022 planetary system^[9]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (years)	Eccentricity	Inclination	Radius
b	4.51+0.91 −0.61 MJ	2.939±0.062	5.297+0.082 −0.073	0.506+0.071 −0.06	71±13 or 109±13°	—

See also

• HD 141937
• HD 142415
• List of extrasolar planets