Article · Wikipedia archive · Last revised Jul 19, 2026

WASP-17

WASP-17, also named Dìwö, is an F-type main sequence star approximately 1,310 light-years away in the constellation Scorpius. It hosts the planet WASP-17b.

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Jul 19, 2026
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WASP-17 / Dìwö
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Scorpius1
Right ascension 15h 59m 50.9492s2
Declination −28° 03′ 42.313″2
Apparent magnitude (V) 11.5003
Characteristics
Evolutionary stage main sequence2
Spectral type F6V4
Astrometry
Radial velocity (Rv)−48.34±1.072 km/s
Proper motion (μ) RA: −8.263(29) mas/yr2
Dec.: −9.427(22) mas/yr2
Parallax (π)2.4811±0.0255 mas2
Distance1,310 ± 10 ly
(403 ± 4 pc)
Details
Mass1.56±0.305 M☉
Radius1.494±0.0635 R☉
Luminosity4.0±0.25 L☉
Surface gravity (log g)4.29±0.085 cgs
Temperature6689±1125 K
Metallicity [Fe/H] [ M / H ] {\displaystyle {\begin{smallmatrix}\left[{\ce {M}}/{\ce {H}}\right]\end{smallmatrix}}}  = −0.190±0.0655 dex
Rotational velocity (v sin i)10.6±1.36 km/s
Age2.65±0.257 Gyr
Other designations
Dìwö, CD−27 10695, TOI-1050, TIC 66818296, WASP-17, TYC 6787-1927-1, 2MASS J15595095-2803422, 1SWASP J155950.94−280342.38
Database references
SIMBADdata
Exoplanet Archivedata

WASP-17, also named Dìwö, is an F-type main sequence star approximately 1,310 light-years away in the constellation Scorpius.2 It hosts the planet WASP-17b.49

The star is depleted of carbon. The carbon to oxygen molar ratio of 0.18±0.04 for WASP-17 is well below the solar ratio of 0.55.10

Nomenclature

The planet was discovered by the SuperWASP project, hence the name WASP-17.

This was one of the systems selected to be named in the 2019 NameExoWorlds campaign during the 100th anniversary of the IAU, which assigned each country a star and planet to be named. This system was assigned to Costa Rica. WASP-17 is named Dìwö, which in the Bribri language means the Sun, and its planet is named Ditsö̀.1112

Planetary system

As of 2009, an exoplanet has been confirmed to orbit the star. The planet, WASP-17b, is unusual in that it is believed to orbit in the opposite direction to the star's spin (a retrograde orbit), and is twice the size of Jupiter, but half its mass.1314 The planet is also named Ditsö̀. It is subject to intensive photo-evaporation, and may be completely destroyed within one billion years from now.15

The WASP-17 planetary system7
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination
(°) 		Radius
b / Ditsö̀ 0.512±0.037 MJ 0.05151±0.00035 3.7354845(19) <0.020 86.83+0.68
−0.53 		1.875±0.0845 RJ
References

References

  1. Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. 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. 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. S2CID 117056033.
  4. Anderson, D. R.; et al. (2010). "WASP-17b: An Ultra-Low Density Planet in a Probable Retrograde Orbit". The Astrophysical Journal. 709 (1): 159–167. arXiv:0908.1553. Bibcode:2010ApJ...709..159A. doi:10.1088/0004-637X/709/1/159. S2CID 53628741.
  5. de Laverny, Patrick; Ligi, Roxanne; Crida, Aurélien; Recio-Blanco, Alejandra; Palicio, Pedro A. (July 2025). "The Gaia spectroscopic catalogue of exoplanets and host stars". Astronomy & Astrophysics. 699: A100. Bibcode:2025A&A...699A.100D. doi:10.1051/0004-6361/202554739. ISSN 0004-6361.
  6. 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. S2CID 16580774.
  7. 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. S2CID 118923163.
  8. "WASP-17". SIMBAD. Centre de données astronomiques de Strasbourg.
  9. "Newfound Planet Orbits Backward". Space.com. 12 August 2009.
  10. Polanski, Alex S.; Crossfield, Ian J. M.; Howard, Andrew W.; Isaacson, Howard; Rice, Malena (2022), "Chemical Abundances for 25 JWST Exoplanet Host Stars with KeckSpec", Research Notes of the American Astronomical Society, 6 (8): 155, arXiv:2207.13662, Bibcode:2022RNAAS...6..155P, doi:10.3847/2515-5172/ac8676
  11. "Approved names". NameExoworlds. Retrieved 2020-01-02.
  12. "International Astronomical Union | IAU". www.iau.org. Archived from the original on 2022-12-05. Retrieved 2020-01-02.
  13. "New exoplanet orbits 'backwards'". August 12, 2009 – via news.bbc.co.uk.
  14. "New-found Planet Orbits Backward".
  15. D. Ehrenreich and J.-M. Désert, "Mass-loss rates for transiting exoplanets", 2011