DH Tauri

DH Tauri, also known as DH Tau, is a type M star, located 140 parsecs (456.619 light years) away. It forms a binary system with DI Tauri 15″ away, and has a substellar companion, either a brown dwarf or massive exoplanet.

DH Tauri

DH Tauri and the b companion (lower left) with the Very Large Telescope Credit: ESO VLT SPHERE; Van Holstein et al.; Processing: Meli_thev
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Taurus
Right ascension	04h 29m 41.558s[1]
Declination	+26° 32′ 58.27″[1]
Apparent magnitude (V)	13.1[2]
Characteristics
Spectral type	M0-M1Ve(T)[3]
Variable type	T Tau[3]
Astrometry
Proper motion (μ)	RA: +7.065[4] mas/yr Dec.: -20.699[4] mas/yr
Parallax (π)	7.3880±.0593 mas[4]
Distance	441 ± 4 ly (135 ± 1 pc)
Details
Mass	0.41[5] M☉
Radius	1.26[5] R☉
Luminosity	0.22[5] L☉
Temperature	3,751[4] K
Age	3.16[5] Myr
Other designations
DH Tau, WDS J04297+2633B, IRAS 04267+2626, 2MASS J04294155+2632582
Database references
SIMBAD	data

Characteristics

DH Tauri is a type M, or red dwarf star, one of the most common types of star in the Milky Way.^[6] It has an apparent magnitude of 13.71 and temperature of 3,751 K. DH Tauri has a mass of 0.41 M_☉ and an estimated radius of 1.26 R_☉, which is unusually large for a red dwarf.

The companion DH Tauri B or b has a mass estimated to be between eight M_J and 50 M_J, making it either a super-Jupiter or brown dwarf.^[7][8] Other sources give a mass as high as 0.03 M_☉, with a bolometric luminosity of 0.01 L_☉.^[9] The spectral type has been classified as M7.5^[9] or M9.25.^[10] The companion has detected water vapor and carbon monoxide in its atmosphere and has a rotational velocity of 9.6 ± 0.7 km/s. This is between 9 and 15% of the breakup speed of DH Tau B. This low rotation is in agreement with magnetic coupling to a circumplanetary disk in the late stages of accretion, which reduces angular momentum of the companion.^[11] The companion, while its host star still having a protoplanetary disk, is still accreting material, being surrounded by a circumsubstellar disk (possibly a circumplanetary disk, depending on its formation history).^[12] It is potentially orbited by a smaller candidate companion DH Tauri Bb (possibly an exomoon) with 1 M_J, and a mass ratio with respect to the brown dwarf of one-tenth.^[13]

The DH Tauri planetary system^[14]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	11±3 MJ	330	120.450	—	—	2.7±0.8 RJ