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WASP-2

Coordinates: Sky map 20h 30m 54.130s, +06° 25′ 46.37″
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WASP-2
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Delphinus
A[1]
Right ascension 20h 30m 54.1282s[2]
Declination +06° 25′ 46.341″[2]
Apparent magnitude (V) +11.98[3]
C[a 1]
Right ascension ~20h 30m 54s[1]
Declination ~+06° 25′ 46″[1]
Characteristics
Spectral type K1.5V + K2-M3[4]
Apparent magnitude (B) ~13[3]
Apparent magnitude (V) ~11.98[3]
Apparent magnitude (J) 10.166±0.027[3]
Apparent magnitude (H) 9.752±0.026[3]
Apparent magnitude (K) 9.632±0.024[3]
Variable type planetary transit[5]
Astrometry
Radial velocity (Rv)−27.70±0.46[2] km/s
Proper motion (μ) RA: 5.631 mas/yr[2]
Dec.: −48.491 mas/yr[2]
Parallax (π)6.5777±0.0270 mas[2]
Distance496 ± 2 ly
(152.0 ± 0.6 pc)
Orbit[6]
PrimaryWASP-2A
CompanionWASP-2B
Semi-major axis (a)106″
Details
WASP-2A
Mass0.843±0.033[7] M☉
Radius0.821±0.013[7] R☉
Luminosity0.507+0.023
−0.029[8] L☉
Surface gravity (log g)4.536±0.015[7] cgs
Temperature5170±60[7] K
Metallicity [Fe/H]0.1±0.2[9] dex
Rotational velocity (v sin i)0.9±0.5[9] km/s
Age7.6+2.5
−3.3[7] Gyr
WASP-2B
Mass0.40±0.02[7] M☉
Temperature3523+28
−19[7] K
Other designations
V357 Del, TOI-5797, TIC 374530847, WASP-2, GSC 00522-01199, 2MASS J20305413+0625463, 1SWASP J203054.12+062546.4, USNO-B1.0 0964-00543604, UCAC2 34018636[3]
Database references
SIMBADA
B
Exoplanet Archivedata

WASP-2 is a binary star system located about 496 light-years away in the Delphinus constellation.[3] The primary is a magnitude 12 orange dwarf star, orbited by a red dwarf star on a wide orbit.[6][10] The star system shows an infrared excess noise of unknown origin.[11]

The primary star hosts one known exoplanet, WASP-2b.[12] Since the planet transits the star, the star is classified as a planetary transit variable and has received the variable star designation V357 Delphini.[5]

Binary star

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]

A re-examination of the WASP-2 spectrum in 2015 resulted in the measurement of the stellar companion's temperature as 3513±28 K, and an angular separation of 0.73 arcseconds.[13]

Planetary system

The primary star has one exoplanet, WASP-2b, a hot Jupiter detected by the SuperWASP project in 2006 using the transit method.[12]

The WASP-2 planetary system[9][7]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b 0.892±0.027 MJ 0.0308±0.0004 2.15222163(42) <0.013 84.81+0.35
−0.27° 		1.060±0.024 RJ

See also

Notes

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

References

  1. ^ a b c d e Daemgen; et al. (2009). "Binarity of transit host stars - Implications for planetary parameters" (PDF). Astronomy and Astrophysics. 498 (2): 567–574. arXiv:0902.2179. Bibcode:2009A&A...498..567D. doi:10.1051/0004-6361/200810988. S2CID 9893376.
  2. ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. ^ a b c d e f g h "WASP-2". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2009-05-04.
  4. ^ Wöllert, Maria; Brandner, Wolfgang; Bergfors, Carolina; Henning, Thomas (2015), "A Lucky Imaging search for stellar companions to transiting planet host stars", Astronomy & Astrophysics, 575: A23, arXiv:1507.01938, Bibcode:2015A&A...575A..23W, doi:10.1051/0004-6361/201424091, S2CID 119250579
  5. ^ a b "V357 Del". General Catalog of Variable Stars - VizieR. Retrieved 3 April 2025.
  6. ^ a b Quarles, Billy; Li, Gongjie; Kostov, Veselin; Haghighipour, Nader (2020), "Orbital stability of circumstellar planets in binary systems", The Astronomical Journal, 159 (3): 80, arXiv:1912.11019, Bibcode:2020AJ....159...80Q, doi:10.3847/1538-3881/ab64fa, S2CID 209444271
  7. ^ a b c d e f g h Southworth, J.; Bohn, A. J.; Kenworthy, M. A.; Ginski, C.; Mancini, L. (2020), "A multiplicity study of transiting exoplanet host stars. II.Revised properties of transiting planetary systems with companions", Astronomy & Astrophysics, A74: 635, arXiv:2001.08225, Bibcode:2020A&A...635A..74S, doi:10.1051/0004-6361/201937334, S2CID 210860775
  8. ^ Addison, Brett; Wright, Duncan J.; et al. (November 2019). "Minerva-Australis. I. Design, Commissioning, and First Photometric Results". Publications of the Astronomical Society of the Pacific. 131 (1005): 115003. arXiv:1901.11231. Bibcode:2019PASP..131k5003A. doi:10.1088/1538-3873/ab03aa.
  9. ^ a b c Bonomo, A. S.; Desidera, S.; et al. (June 2017). "The GAPS Programme with HARPS-N at TNG. XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets". Astronomy & Astrophysics. 602: A107. arXiv:1704.00373. Bibcode:2017A&A...602A.107B. doi:10.1051/0004-6361/201629882.
  10. ^ Precise Differential Analysis of Stellar Metallicities: Application to Solar Analogs Including 16 Cyg A and B
  11. ^ Sada, Pedro V.; Deming, Drake; Jennings, Donald E.; Jackson, Brian k.; Hamilton, Catrina M.; Fraine, Jonathan; Peterson, Steven W.; Haase, Flynn; Bays, Kevin; Lunsford, Allen; o'Gorman, Eamon (2012), "Extrasolar Planet Transits Observed at Kitt Peak National Observatory", Publications of the Astronomical Society of the Pacific, 124 (913): 212–229, arXiv:1202.2799, Bibcode:2012PASP..124..212S, doi:10.1086/665043, S2CID 29665395
  12. ^ 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/0609688. Bibcode:2007MNRAS.375..951C. doi:10.1111/j.1365-2966.2006.11350.x. S2CID 735515.
  13. ^ Piskorz, Danielle; Knutson, Heather A.; Ngo, Henry; Muirhead, Philip S.; Batygin, Konstantin; Crepp, Justin R.; Hinkley, Sasha; Morton, Timothy D. (2015), "Friends of Hot Jupiters. III. An Infrared Spectroscopic Search for Low-Mass Stellar Companions", The Astrophysical Journal, 814 (2): 148, arXiv:1510.08062, Bibcode:2015ApJ...814..148P, doi:10.1088/0004-637X/814/2/148, S2CID 11525988


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