WASP-8

WASP-8 is a magnitude 9.9 main-sequence yellow dwarf star. It is reported to be a G-type star of temperature 5600 K, mass of 0.93 solar masses, radius of 0.93 solar radius, and a luminosity of 0.79 of solar luminosity. There is a companion star located 4 arcseconds away with the same proper motion indicating a stellar binary system.[3]

WASP-8
Observation data
Epoch J2000      Equinox J2000
Constellation Sculptor
Right ascension  23h 59m 36.0711s[1]
Declination −35° 01′ 52.920″[1]
Apparent magnitude (V) 9.9
Characteristics
Spectral type G6
Astrometry
Proper motion (μ) RA: 109.878±0.571[1] mas/yr
Dec.: 7.370±0.615[1] mas/yr
Parallax (π)11.20 ± 0.27[1] mas
Distance291 ± 7 ly
(89 ± 2 pc)
Details
Mass0.93 M☉
Radius0.93 R☉
Luminosity0.79 L☉
Temperature5600 K
Rotational velocity (v sin i)1.90±0.05[2] km/s
Age3–5[3] Gyr
Other designations
TYC 7522-505-1, WDS J23596-3502A[4]
Database references
SIMBADdata

Planetary system

The star is orbited by two known extrasolar planet, designated WASP-8b and WASP-8c. They was catalogued as part of the SuperWASP mission and discovered by the astronomical transit method.[3] WASP-8c has the longest orbital period of any exoplanet discovered by WASP with a period of 4,323 days, over 400 times the period of the second-furthest planet, WASP-117b with a period of 10.02 days.

Measurements of WASP-8b's radius and mass give it an estimated density of 2.53 g/cm3, about twice the density of Jupiter.

The WASP-8 planetary system
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 2.23 MJ 0.0793 8.16 0.3082 88.52° 1.17 RJ
c 9.45 MJ 5.28 4323 — — —

See also
Artist's impression of a star like WASP-8.

References
  1. Brown, A. G. A; et al. (2016). "Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties". Astronomy and Astrophysics. 595. A2. arXiv:1609.04172. Bibcode:2016A&A...595A...2G. doi:10.1051/0004-6361/201629512.Gaia Data Release 1 catalog entry
  2. Bourrier, V.; et al. (2017). "Refined architecture of the WASP-8 system: A cautionary tale for traditional Rossiter-McLaughlin analysis". Astronomy and Astrophysics. 599. A33. arXiv:1611.07985. Bibcode:2017A&A...599A..33B. doi:10.1051/0004-6361/201629973.
  3. Queloz, D.; et al. (2010). "WASP-8b: a retrograde transiting planet in a multiple system". Astronomy and Astrophysics. 517. L1. arXiv:1006.5089. Bibcode:2010A&A...517L...1Q. doi:10.1051/0004-6361/201014768.
  4. "NAME WASP-8 A -- Star in double system". SIMBAD Astronomical Database. Centre de données astronomiques de Strasbourg. Retrieved 2014-09-29.


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