HD 142

HD 142 is a wide binary star^[5] system in the southern constellation of Phoenix. The main component has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.7.^[3] The system is located at a distance of 85.5 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +6 km/s.^[18]

HD 142

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Phoenix[1]
HD 142 A
Right ascension	00h 06m 19.1754s[2]
Declination	−49° 04′ 30.6741″[2]
Apparent magnitude (V)	5.711±0.003[3]
HD 142 B
Right ascension	00h 06m 19.1480s[4]
Declination	−49° 04′ 34.9177″[4]
Apparent magnitude (V)	+11.5[5]
Characteristics
Evolutionary stage	main sequence
Spectral type	F7V[6] + K8.5-M1.5[7]
B−V color index	0.519±0.011[8]
Astrometry
HD 142 A
Radial velocity (Rv)	5.76±0.12[9] km/s
Proper motion (μ)	RA: 575.099[9] mas/yr Dec.: −40.874[9] mas/yr
Parallax (π)	38.1945±0.0355 mas[9]
Distance	85.39 ± 0.08 ly (26.18 ± 0.02 pc)
Absolute magnitude (MV)	3.66±0.02[10]
HD 142 B
Proper motion (μ)	RA: 566.984[11] mas/yr Dec.: −17.387[11] mas/yr
Parallax (π)	38.2306±0.0349 mas[11]
Distance	85.31 ± 0.08 ly (26.16 ± 0.02 pc)
Details
HD 142 A
Mass	1.25±0.01[12] M☉
Radius	1.41±0.11[13] R☉
Luminosity	2.9[13] L☉
Surface gravity (log g)	4.45±0.07[12] cgs
Temperature	6,349±26[12] K
Metallicity [Fe/H]	+0.133±0.020[12] dex
Rotational velocity (v sin i)	9.58±0.74[14] km/s
Age	2.50+0.32 −0.28[12] Gyr
HD 142 B
Mass	0.54[15] M☉
Other designations
HD 142A: CD−49°14337, HD 142, HIP 522, HR 6, SAO 214963, WDS J00063-4905A[16]
HD 142B: CD−49°14337B, WDS J00063-4905B, NLTT 218, 2MASS J00061919-4904348[17]
Database references
SIMBAD	data

The primary component is an F-type main-sequence star with a stellar classification of F7V,^[6] which indicates it is undergoing core hydrogen fusion. It is an estimated 2.5 billion years old^[12] and is spinning with a projected rotational velocity of 10 km/s.^[14] The star has 1.25 times the mass of the Sun^[12] and 1.4 times the Sun's radius. It is radiating 2.9 times the luminosity of the Sun from its photosphere^[13] at an effective temperature of 6,349 K.^[12]

A magnitude 11.5^[5] companion star was detected in 1894 making this a binary star system.^[19] The binary companion was confirmed to be gravitationally bound in 2007 and determined to be a red dwarf of spectral type K8.5-M1.5^[7] with 54% of the Sun's mass.^[15] The pair have a projected separation of 120.6 AU.^[15]

Planetary system

In 2001, the Anglo-Australian Planet Search team led by Chris Tinney announced the discovery of an extrasolar planet orbiting the primary star.^[20][21] An additional linear trend in the radial velocity data was noticed in 2006^[22] that could have been due to another planet or to the stellar companion.^[23] In 2012, additional measurements allowed the detection of a second planet. A third possible planet with a period of 108 days was seen in the data, but with a false alarm probability of five percent.^[24] Another paper by the same team updated the parameters for b and c but did not mention the possible planet d.^[25]

An astrometric measurement of HD 142 b's inclination and true mass was published in 2022 as part of Gaia DR3.^[26] Another 2022 study determined the inclination and true mass of planet c, and confirmed the existence of planet d.^[27]

The HD 142 A planetary system^[26][27]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
d	≥0.260+0.032 −0.036 MJ	0.474+0.021 −0.023	108.5±0.1	0.130+0.103 −0.085	—	—
b	7.1±1.0 MJ	1.039+0.046 −0.051	351.4±0.4	0.158+0.033 −0.030	59±7°	—
c	10.901+1.278 −0.937 MJ	9.811+0.515 −0.520	10,159.6+384.8 −321.9	0.277+0.026 −0.027	90.374+10.495 −12.319°	—

See also

• List of extrasolar planets