WASP-18
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Phoenix[1] |
| Right ascension | 01h 37m 25.034s[2] |
| Declination | –45° 40′ 40.39″[2] |
| Apparent magnitude (V) | 9.273[3] |
| Characteristics | |
| Spectral type | F6[4] |
| Astrometry | |
| Proper motion (μ) | RA: 26.52±0.95[2] mas/yr Dec.: 18.79±1.06[2] mas/yr |
| Parallax (π) | 10.06 ± 1.07 mas[2] |
| Distance | approx. 320 ly (approx. 100 pc) |
| Details | |
| Mass | 1.256±0.13[4] M☉ |
| Radius | 1.216+0.067 −0.054[4] R☉ |
| Surface gravity (log g) | 4.37±0.03[5] cgs |
| Temperature | 6368±66[5] K |
| Metallicity [Fe/H] | 0.11±0.08[5] dex |
| Rotational velocity (v sin i) | 11.9±1.2[5] km/s |
| Age | 0.5–1.5[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
WASP-18 is a magnitude 9 star located in the Phoenix constellation of the southern hemisphere.[1] It has a mass of 1.25 solar masses.[6]
In 2009, the SuperWASP project announced that a large, hot Jupiter type extrasolar planet, WASP-18b, was orbiting very close to this star.[4]
Observations from the Chandra X-ray Observatory failed to find any X-rays coming from WASP-18, and it is thought that this is caused by WASP-18b disrupting the star's magnetic field by causing a reduction in convection in the star's atmosphere. Tidal forces from the planet may also explain the higher amounts of lithium measured in earlier optical studies of WASP-18.[7]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ~10[4] MJ | 0.020206 | 0.94145299[1] | 0.0092 | — | — |
See also
References
- ^ a b c "WASP-18b". Exoplanet Transit Database. Retrieved 2009-08-29.
- ^ a b c d e van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.Vizier catalog entry
- ^ Maxted, P. F. L.; et al. (2011). "UBV(RI)C photometry of transiting planet hosting stars". Monthly Notices of the Royal Astronomical Society. 418 (2): 1039–1042. arXiv:1108.0349. Bibcode:2011MNRAS.418.1039M. doi:10.1111/j.1365-2966.2011.19554.x.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ a b c d e f Hellier, Coel; et al. (2009). "An orbital period of 0.94days for the hot-Jupiter planet WASP-18b" (PDF). Nature. 460 (7259): 1098–1100. Bibcode:2009Natur.460.1098H. doi:10.1038/nature08245. PMID 19713926.
- ^ a b c d Torres, Guillermo; et al. (2012). "Improved Spectroscopic Parameters for Transiting Planet Hosts". The Astrophysical Journal. 757 (2). 161. arXiv:1208.1268. Bibcode:2012ApJ...757..161T. doi:10.1088/0004-637X/757/2/161.
- ^ PlanetQuest: WASP-18 b
- ^ "NASA's Chandra X-ray Observatory Finds Planet That Makes Star Act Deceptively Old". Chandra X-ray Observatory. Retrieved 20 September 2014.
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