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]
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 |
Distance | 291 ± 7 ly (89 ± 2 pc) |
Details | |
Mass | 0.93 M☉ |
Radius | 0.93 R☉ |
Luminosity | 0.79 L☉ |
Temperature | 5600 K |
Rotational velocity (v sin i) | 1.90±0.05[2] km/s |
Age | 3–5[3] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
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.
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 | — | — | — |
References
- 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
- 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.
- 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.
- "NAME WASP-8 A -- Star in double system". SIMBAD Astronomical Database. Centre de données astronomiques de Strasbourg. Retrieved 2014-09-29.
External links
- WASP planets
- "Notes for star WASP-8". The Extrasolar Planets Encyclopaedia. Archived from the original on 2008-08-03. Retrieved 2008-08-07.