HD 106906

HD 106906 is a binary star^[6] system in the southern constellation of Crux. It is too faint to be visible to the naked eye, having a combined apparent visual magnitude of 7.80.^[2] The distance to this system is approximately 337 light years based on parallax, and it is receding from the Sun with a radial velocity of +10 km/s.^[2] It is a member of the Lower Centaurus–Crux group of the Scorpius–Centaurus OB association of co-moving stars.^[4]

HD 106906

Star map shows star position on the northern edge of the constellation Crux
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Crux
Right ascension	12h 17m 53.191430s[1]
Declination	−55° 58′ 31.8904″[1]
Apparent magnitude (V)	7.80[2]
Characteristics
Spectral type	F5 V[3]
B−V color index	0.458±0.003[2]
Astrometry
Radial velocity (Rv)	+10.2±1.7[2] km/s
Proper motion (μ)	RA: −39.014[1] mas/yr Dec.: −12.872[1] mas/yr
Parallax (π)	9.6774±0.0429 mas[1]
Distance	337 ± 1 ly (103.3 ± 0.5 pc)
Absolute magnitude (MV)	2.99[2]
Details
Mass	1.355[4] M☉
Radius	2.03+0.11 −0.10[1] R☉
Luminosity	6.56±0.04[1] L☉
Temperature	6,484+157 −168[1] K
Metallicity [Fe/H]	−0.04±0.08[2] dex
Age	13±2[4] Myr
Other designations
CD−55°4537, HD 106906, HIP 59960, SAO 239819, 2MASS J12175319-5558319[5]
Database references
SIMBAD	data

This is a double-lined spectroscopic binary system consisting of two F-type main-sequence stars with similar masses and a matching stellar classification of F5 V.^[6] Their orbital period is less than 100 days.^[4]

Planetary system

Edge-on disc of gas and dust present around the binary star system HD 106906

A distant circumbinary planet—HD 106906 b—is orbiting the pair at a projected separation of 732±30 AU with a period of at least 3,000 years. An infrared excess around the binary is coming from a circumstellar debris disk that is being viewed edge-on. This has a pronounced asymmetrical shape, extending 120 AU on the east side and out to 550 AU to the west.^[4] Planetary orbit is inclined to the debris disk by 39⁺²⁰
₋₁₅ degrees, and planet itself is visible nearly pole-on, having a large axial tilt.^[7]

The HD 106906 planetary system^[8]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (years)	Eccentricity	Inclination	Radius
debris disk	65–550 AU				84.65 ± 0.35°	—
b	11 ± 2 MJ	~732 ± 30 AU	> 3000	—	64°	1.54 +0.04 −0.05[9] RJ