WASP-8

WASP-8 is a binary star system 294 light-years (90 parsecs) away. The star system is much younger than the Sun at 300 million to 1.2 billion years age, and is heavily enriched in heavy elements, having nearly twice the concentration of iron compared to the Sun.^[6]

WASP-8

Artist's impression of a star like WASP-8
Observation data Epoch J2000      Equinox J2000
Constellation	Sculptor[1]
Right ascension	23h 59m 36.07119s[2]
Declination	−35° 01′ 52.9236″[2]
Apparent magnitude (V)	9.87[3]
Characteristics
WASP-8A
Evolutionary stage	main-sequence
Spectral type	G8V[4]
WASP-8B
Spectral type	M[5]
Astrometry
Radial velocity (Rv)	−1.38±0.26[2] km/s
Proper motion (μ)	RA: 109.752 mas/yr[2] Dec.: 7.615 mas/yr[2]
Parallax (π)	11.1052±0.0175 mas[2]
Distance	293.7 ± 0.5 ly (90.0 ± 0.1 pc)
Position (relative to WASP-8A)[5]
Component	WASP-8B
Epoch of observation	2016
Angular distance	4.520±0.005″
Position angle	170.9±0.1°
Projected separation	408 AU
Details[6]
WASP-8A
Mass	1.093±0.024 M☉
Radius	0.976±0.020 R☉
Luminosity	0.79 L☉
Surface gravity (log g)	4.498±0.018 cgs
Temperature	5600±80 K
Metallicity [Fe/H]	0.29±0.03 dex
Rotational velocity (v sin i)	1.90±0.05[7] km/s
Age	0.3+0.9 −0.1 Gyr
WASP-8B
Mass	0.53±0.02 M☉
Temperature	3758+47 −43 K
Other designations
CD−35 16019, CPD−35 9465, SAO 214901, PPM 304426, WDS J23596-3502A, TOI-191, TIC 183532609, WASP-8, TYC 7522-505-1, 2MASS J23593607-3501530[3]
Database references
SIMBAD	A
	B
Exoplanet Archive	data

The primary, WASP-8A, is a magnitude 9.9 main-sequence yellow dwarf star. It is reported to be a G-type star with a temperature of 5600 K and has a mass 1.093±0.024, a radius 0.976±0.020 and a luminosity of 0.79 times that of the Sun. There is a companion star WASP-8B located 4.5 arcseconds away with the same proper motion, indicating a stellar binary system.^[8] The binarity was confirmed in 2020.^[5] The axis orientation of the primary star is uncertain, but it is close to pointing one of the poles to the Earth.^[7]

Planetary system

The primary star is orbited by two known exoplanets, designated WASP-8b and WASP-8c. WASP-8b was discovered in 2010 by the astronomical transit method and was catalogued as part of the SuperWASP mission.^[8] WASP-8c was discovered in late 2013 with the radial velocity method.^[9]

The WASP-8 planetary system^[6][9]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	2.216±0.035 MJ	0.0817±0.0006	8.158715(16)[10]	0.3057±0.0046[10]	88.51±0.09°	1.165±0.032 RJ
c	≥9.45+2.26 −1.04 MJ	5.28+0.63 −0.34	4323+740 −380	0	—	—

See also

• SuperWASP