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Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Delphinus
Right ascension 20h 30m 54.1300s[2]
Declination +06° 25′ 46.37″[2]
Apparent magnitude (V) +11.98[2]
Right ascension ~20h 30m 54s[1]
Declination ~+06° 25′ 46″[1]
Apparent magnitude (V) 15.38[1]
Spectral type K1V[3]/M[1]
Apparent magnitude (B) ~13[2]
Apparent magnitude (V) ~11.98[2]
Apparent magnitude (J) 10.166±0.027[2]
Apparent magnitude (H) 9.752±0.026[2]
Apparent magnitude (K) 9.632±0.024[2]
Proper motion (μ) RA: 3.0[2] mas/yr
Dec.: -53.1[2] mas/yr
Distance 469 ly
(144 pc)
Mass 0.77[1]/0.48[1] M
Radius 0.834 ±0.08 R
Temperature 5200 ±200 K
Other designations
GSC 00522-01199, 1SWASP J203054.12+062546.4
Database references
Extrasolar Planets

WASP-2 is a magnitude 12 orange dwarf star located about 469 light-years away in the Delphinus constellation.[2]

Planetary system[edit]

This star has one extrasolar planet WASP-2b, detected by the SuperWASP project in 2006.[3]

The WASP-2 planetary system
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b 0.847 (± 0.045) MJ 0.03138 (± 0.011) 2.15222144 (± 4e-07) 0

Binary star[edit]

In 2008 a study was undertaken of fourteen stars with exoplanets that were originally discovered using the transit method through relatively small telescopes. These systems were re-examined with the 2.2 m (87 in) reflector telescope at the Calar Alto Observatory in Spain. This star system, along with two others, was determined to be a previously unknown binary star system. The previously unknown secondary star is a dim magnitude 15 M-type star separated by about 111 AU from the primary, appearing offset from the primary by about one arc second in the images. This discovery resulted in a recalculation of parameters for both the planet and the primary star.[1]


  • Note b: The secondary star is identified with a "C" suffix so as to not confuse it with the planetary designation suffix "b".[1]

See also[edit]


  1. ^ a b c d e f g h i Daemgen; et al. (2009). "Binarity of transit host stars - Implications for planetary parameters" (PDF). Astronomy and Astrophysics. 498 (2): 567–574. arXiv:0902.2179Freely accessible. Bibcode:2009A&A...498..567D. doi:10.1051/0004-6361/200810988. 
  2. ^ a b c d e f g h i j k "SIMBAD query result: GSC 00522-01199 -- Star". Centre de Données astronomiques de Strasbourg. Retrieved 2009-05-04. 
  3. ^ a b Cameron, A. Collier; et al. (2007). "WASP-1b and WASP-2b: two new transiting exoplanets detected with SuperWASP and SOPHIE". Monthly Notices of the Royal Astronomical Society. 375 (3): 951–957. arXiv:astro-ph/0609688Freely accessible. Bibcode:2007MNRAS.375..951C. doi:10.1111/j.1365-2966.2006.11350.x. 

External links[edit]

  • "WASP-2". Exoplanets. Retrieved 2009-05-04. 

Coordinates: Sky map 20h 30m 54.130s, +06° 25′ 46.37″