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Observation data
Epoch J2000      Equinox J2000
Constellation Lynx
Right ascension 09h 20m 24s
Declination +33° 52′ 56″
Apparent magnitude (V) 10.42[1]
Spectral type G1 IV
Surface gravity (log g) 4.04 ± 0.2[1] cgs
Temperature 5826[2] K
Metallicity [Fe/H] 0 ± 0.2[2] dex
Rotational velocity (v sin i) < 4.9[1] km/s
Other designations
2MASS J09202471+3352567, GPM 140.102992+33.882691, 1SWASP J092024.70+335256.6, USNO-B1.0 1238-00183620[3]

WASP-13 is a star in the Lynx constellation. The star is similar, in terms of metallicity and mass, to the Sun, although it is hotter and most likely older. The star was first observed in 1997, according to the SIMBAD database, and was targeted by SuperWASP after the star was observed by one of the SuperWASP telescopes beginning in 2006. Follow-up observations on the star led to the discovery of planet WASP-13b in 2008; the discovery paper was published in 2009.[1]

Observational history[edit]

The telescope housed inside the Haute-Provence Observatory, which was used to collect radial velocity measurements.

According to SIMBAD, WASP-13 was first observed in 1997, when it was catalogued by astronomers measuring the proper motion of stars in regions of the sky where galaxies are detected.[3] Between November 27, 2006, and April 1, 2007, the SuperWASP-North telescope in the Canary Islands observed WASP-13; analysis of the data suggested that a planet could be in the orbit of the star.[1]

Follow-up observations were conducted by a team of British, Spanish, French, Swiss and American astronomers using the photometer on the James Gregory Telescope in Scotland; using visual comparisons to the nearby bright star HD 80408, the star's light curve was better defined. In combination with measurements of WASP-13's spectrum measured using the SOPHIE échelle spectrograph at the Haute-Provence Observatory in France, the star's radial velocity was also discovered. The Fibre-Fed Echelle Spectrograph on the Nordic Optical Telescope gathered additional measurements of WASP-13's spectrum, allowing astronomers to determine WASP-13's characteristics. Use of SOPHIE's data led to the discovery of the planet WASP-13b in 2008; the planet was reported in 2009.[1]

Based on SIMBAD's archive, WASP-13 was included in ten more papers between its discovery and 2010.[3]


WASP-13 is a sunlike, G-type star that is situated approximately 156 parsecs (509 light years) in the Lynx constellation. With an apparent magnitude of 10.42, the star cannot be seen with the unaided eye from the perspective of someone on Earth. The star's effective temperature, at 5826 K, is hotter than that of the Sun. However, its metallicity is similar; this can be seen in how the concentration of iron, or [Fe/H], is approximately 0.[2] WASP-13's surface gravity is measured at 4.04 km/s2, while the rate at which it rotates is at most 4.9 km/s.[1]

WASP-13 has a mass that is 1.03 times the mass of the Sun and a radius that is 1.34 times the Sun's radius. Measurements of its lithium content suggest that the star has used up all of its helium and is now fusing lithium in the shell around its core. With this, its estimated age is 8.5 billion years, over twice the age of the Sun, but this age may vary to any point between 4.4 and 14 billion years in age because of the high uncertainty surrounding this aspect of the star's age.[1]

Planetary system[edit]

Main article: WASP-13b

WASP-13b is a planet that orbits its host star at a distance of 0.0527 AU, or approximately 5.27% of the mean distance between the Earth and Sun. The planet completes an orbit every 4.35298 days, or approximately 4 days and 8.5 hours. WASP-13b's estimated mass is 0.46 times the mass of Jupiter, while its radius is about 1.21 times that of the planet.[2]

The WASP-13 planetary system[2]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b 0.485 +0.058
0.05379 +0.00059
4.353011 (± 1.3e-05) (0)


  1. ^ a b c d e f g h Skillen, I.; et al. (2009). "The 0.5Mj transiting exoplanet WASP-13b". Astronomy and Astrophysics. 502 (1): 391–394. arXiv:0905.3115free to read. Bibcode:2009A&A...502..391S. doi:10.1051/0004-6361/200912018. 
  2. ^ a b c d e Jean Schneider (2009). "Notes for star WASP-13". Extrasolar Planets Encyclopedia. Retrieved 28 May 2011. 
  3. ^ a b c "SIMBAD query result". SIMBAD. Centre de données astronomiques de Strasbourg. 2010. Retrieved 6 June 2011. 

Coordinates: Sky map 09h 20m 24s, +33° 52′ 56″