HD 68402

HD 68402 is a solitary star located in the circumpolar constellation Volans. With an apparent magnitude of 9.09,^[2] it is invisible to the naked eye but can be seen with an amateur telescope. This star is located at a distance of 256 light years based on its parallax shift but is drifting away at a rate of 11.60 km/s.^[4]

HD 68402

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Volans
Right ascension	08h 05m 23.69129s[1]
Declination	−74° 24′ 37.4873″[1]
Apparent magnitude (V)	9.09 ± 0.02[2]
Characteristics
Spectral type	G5 IV/V[3]
B−V color index	+0.68[2]
Astrometry
Radial velocity (Rv)	11.60 ± 0.49[4] km/s
Proper motion (μ)	RA: −78.195 mas/yr[1] Dec.: +78.973 mas/yr[1]
Parallax (π)	12.7204±0.0101 mas[1]
Distance	256.4 ± 0.2 ly (78.61 ± 0.06 pc)
Absolute magnitude (MV)	+4.66[5]
Details[6]
Mass	1.12 ± 0.05 M☉
Radius	1.02 ± 0.05 R☉
Luminosity	1.17+0.06 −0.07 L☉
Surface gravity (log g)	4.43 ± 0.04[7] cgs
Temperature	5,907 ± 68[7] K
Metallicity [Fe/H]	+0.29 ± 0.10 dex
Rotational velocity (v sin i)	2.9 ± 0.2 km/s
Age	1 ± 0.9[7] Gyr
Other designations
CD−74°392, CPD−74°486, HD 68402, HIP 39589
Database references
SIMBAD	data
Exoplanet Archive	data

HD 68402 has a classification of G5 IV/V,^[3] which indicates that it is a G5 star with the characteristics of a subgiant and main-sequence star. Contrary to its classification, it is actually a G1 dwarf.^[6] At present it is slightly more massive than the Sun and has a similar radius to the latter.^[6] It radiates at 1.17^[6] times the luminosity of the Sun from its photosphere at an effective temperature of 5,907 K,^[7] which gives it a yellow hue. At an age of 1 billion years HD 68402^[7] has a projected rotational velocity of almost 3 km/s and is metal rich like most planetary hosts (1.94 times to be exact).^[6]

Planetary system

In 2017, a superjovian planet was discovered using doppler spectroscopy data from HARPS and CORALIE.^[6] In 2023, the inclination and true mass of HD 68402 b were determined via astrometry.^[8]

The HD 68402 planetary system^[8]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (years)	Eccentricity	Inclination	Radius
b	7.9+1.7 −1.5 MJ	2.239+0.11 −0.075	3.15+0.22 −0.14	0.225+0.15 −0.082	20.3+6.2 −4.1 or 159.7+4.1 −6.2°	—