HD 37605

HD 37605 is a star in the equatorial constellation of Orion. It is orange in hue but is too faint to be visible to the naked eye, having an apparent visual magnitude of 8.67.^[2] Parallax measurements yield a distance estimate of 152 light years from the Sun. It has a high proper motion^[3] and is drifting closer with a radial velocity of −22 km/s.^[1]

HD 37605

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Orion
Right ascension	05h 40m 01.7283s[1]
Declination	+06° 03′ 38.073″[1]
Apparent magnitude (V)	8.67[2]
Characteristics
Spectral type	K0 V[3]
B−V color index	0.827±0.005[2]
Astrometry
Radial velocity (Rv)	−22.08±0.15[1] km/s
Proper motion (μ)	RA: 52.246(26) mas/yr[1] Dec.: −247.136(17) mas/yr[1]
Parallax (π)	21.4364±0.0224 mas[1]
Distance	152.2 ± 0.2 ly (46.65 ± 0.05 pc)
Absolute magnitude (MV)	5.46[2]
Details[4]
Mass	0.98±0.01 M☉
Radius	0.89±0.01 R☉
Luminosity	0.602±0.002 L☉
Surface gravity (log g)	4.52±0.01 cgs
Temperature	5,380±13 K
Metallicity [Fe/H]	0.25±0.04[5] dex
Rotation	57.67[3] days
Rotational velocity (v sin i)	4.5[6] km/s
Age	1.8±1.0 or 7[3] Gyr
Other designations
BD+05°985, HD 37605, HIP 26664, SAO 113015, LTT 11695[7]
Database references
SIMBAD	data
Exoplanet Archive	data

This object is a K-type main-sequence star with a stellar classification of K0 V.^[3] It is an inactive, metal-rich star. Age estimates range from 1.8^[4] up to 7^[3] billion years old, and it is spinning with a projected rotational velocity of 4.5 km/s.^[6] The star has 98% of the mass of the Sun and 89% of the Sun's radius. It is radiating 60% of the luminosity of the Sun from its photosphere at an effective temperature of 5,380 K.^[4]

Planets

There are two giant planets known in orbit. Planet b was discovered in 2004^[8] and planet c was discovered eight years later. The planets do not transit relative to Earth; b's maximum inclination is 88.1%.^[3][9]

In a simulation, HD 37605 b's orbit "sweeps clean" most test particles within 0.5 AU; leaving only asteroids "in low-eccentricity orbits near the known planet’s apastron distance, near the 1:2 mean-motion resonance" with oscillating eccentricity up to 0.06, and also at 1:3 with oscillating eccentricity up to 0.4. Also, observation has ruled out planets heavier than 0.7 Jupiter mass with a period of one year or less; which still allows for planets at 0.8 AU or more.^[10]

The HD 37605 planetary system^[11]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	≥2.69±0.3 MJ	0.277±0.015	55.01292±0.00062	0.6745±0.0019	—	—
c	≥3.19±0.38 MJ	3.74±0.21	2720±15	0.03±0.012	—	—