XO-3

This article is about the star. For the computer from the 'One Laptop Per Child' initiative, see OLPC XO-3.

XO-3 is a star 670 light-years (210 parsecs) away in the constellation Camelopardalis. The star has a magnitude of 10 and is not visible to the naked eye but is visible through a small telescope.^[3] A search for a binary companion star using adaptive optics at the MMT Observatory was negative.^[7]

XO-3

Observation data Epoch J2000      Equinox J2000
Constellation	Camelopardalis[1]
Right ascension	04h 21m 52.7048s[2]
Declination	+57° 49′ 01.889″[2]
Apparent magnitude (V)	9.80 ± 0.03[3]
Characteristics
Evolutionary stage	main sequence[2]
Spectral type	F5V[3]
Apparent magnitude (B)	10.25 ± 0.03[3]
Apparent magnitude (V)	9.80 ± 0.03[3]
Apparent magnitude (J)	9.013 ± 0.029[4]
Apparent magnitude (H)	8.845 ± 0.018[4]
Apparent magnitude (K)	8.791 ± 0.019[4]
Astrometry
Radial velocity (Rv)	−11.14±0.47[2] km/s
Proper motion (μ)	RA: −2.721(27) mas/yr[2] Dec.: 4.186(23) mas/yr[2]
Parallax (π)	4.8687±0.0261 mas[2]
Distance	670 ± 4 ly (205 ± 1 pc)
Details[5]
Mass	1.213±0.066 M☉
Radius	1.377±0.083 R☉
Luminosity	2.92+0.59 −0.48 L☉
Surface gravity (log g)	4.244±0.041 cgs
Temperature	6429±100 K
Metallicity [Fe/H]	−0.177±0.080 dex
Rotational velocity (v sin i)	18.54±0.17 km/s
Age	2.82+0.58 −0.82 Gyr
Other designations
XO-3, BD+57 793, TOI-1676, TIC 8400842, TYC 3727-1064-1, GSC 03727-01064, 2MASS J04215269+5749018[6]
Database references
SIMBAD	data
Exoplanet Archive	data

Planetary system

In 2007 the gas giant exoplanet XO-3b was discovered by the XO Telescope using the transit method. This object may be classed as a brown dwarf because of its high mass, near the ~13 M_J limit for deuterium fusion.^[3][8] The planetary orbit is misaligned from the stellar rotation.^[9][10]

The XO-3 planetary system^[11]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	11.70+0.42 −0.43 MJ	0.04539+0.00081 −0.00084	3.19153285(58)	0.27587+0.00071 −0.00067	84.20±0.54°	1.217±0.073 RJ