XO-6b

XO-6b is a transiting exoplanet, orbiting the star XO-6 around 760 light years (230 parsecs) away from Earth. It was discovered in 2016 by the XO planet search team.^[5][6]

XO-6

Jupiter compared to XO-6b
Discovery[1]
Discovery site	Haleakalā Observatory in Maui, Hawaii
Discovery date	December 8th, 2016
Detection method	Transit
Orbital characteristics[2]
Semi-major axis	0.082±0.008 AU[3]
Eccentricity	0.00 (fixed)[1]
Orbital period (sidereal)	3.7649923+45 −46 d
Inclination	84.77°+0.82° −0.66°
Time of periastron	2,458,843.93943±0.00012 JD[1]
Semi-amplitude	<450 m/s[1]
Physical characteristics
Mean radius	1.52±0.17 RJ[4]
Mass	1.73±0.20 MJ[2]
Temperature	1,670±25 K[2]

Characteristics

XO-6b is classified as a hot Jupiter.^[1] The planet has an orbital period of just 3.8 days and an average orbital separation of 0.082 astronomical units.^[1][3][2] As of such, it is highly irradiated, with a surface temperature estimated to be around 1,670 K (1,400 °C).^[2] The planet's mass is estimated at 1.73±0.20 M_J.^[2] The discovery paper suggested a very large radius of 2.07±0.22 R_J,^[1] which would make it among the largest known exoplanets, but more recent papers, considering the measurements of the host star's distance by the Gaia satellite, found the radius to be smaller, at around 1.5 R_J.^[3][4]

Host star

XO-6

Observation data Epoch J2000      Equinox J2000
Constellation	Camelopardalis[7]
Right ascension	06h 19m 10.3709s[8]
Declination	+73° 49′ 39.587″[8]
Apparent magnitude (V)	10.247±0.004[9]
Characteristics
Evolutionary stage	Main sequence[8]
Spectral type	F5[1]
Variable type	Planetary transit variable[1]
Astrometry
Radial velocity (Rv)	2.5±0.9[8] km/s
Proper motion (μ)	RA: −16.628 mas/yr[8] Dec.: −22.275 mas/yr[8]
Parallax (π)	4.3131±0.0232 mas[8]
Distance	756 ± 4 ly (232 ± 1 pc)[8]
Details
Mass	1.297±0.040[4] M☉
Radius	1.417±0.029[4] R☉
Luminosity	3.36[8] L☉
Surface gravity (log g)	4.291±0.091[9] cgs
Temperature	6,724±164[9] K
Age	1.89±0.46[4] Gyr
Other designations
BD+73°323, TOI-1651, TIC 138168780
Database references
SIMBAD	data

XO-6b orbits XO-6, a faint 10th magnitude star in the constellation Camelopardalis.^[7] Due to its magnitude, this star is too faint to be seen with the naked eye, but can be seen with a telescope.^{[citation needed]} XO-6 is a F-type main-sequence star^[1][8] with about 1.30 times the mass of the Sun. It is also radiating three times as bright,^[8] and is 1.4 times the size of the Sun.^[4] It is also hotter, with a temperature of 6724 K,^[9] which gives it the typical hue of an F-type star.^[10] Unlike most other stars of its kind, XO-6 rotates rapidly at a rate of 43 km/s.^{[citation needed]}