|Discovered by||Hatzes et al.|
|Discovery site||United States|
|Discovery date||16 June 2006|
|1.64 ± 0.27 AU (245 ± 40 million km)|
|Eccentricity||0.02 ± 0.03|
|589.64 ± 0.81 d|
1.61432 ± 0.00222 y
|2,447,739.02 ± 4.5|
|Semi-amplitude||41.0 ± 1.6|
Pollux b, also designated β Geminorum b (Latinized to beta Geminorum b, abbreviated, β Gem b) and HD 62509 b, formally named Thestias /ˈθɛstiəs/, is an extrasolar planet approximately 34 light-years away in the constellation of Gemini (the Twins). This planet was discovered orbiting the star Pollux in 2006 by astronomer Artie P. Hatzes, confirming his hypothesis originally published in 1993. The planet has at least twice the mass of Jupiter. It moves around Pollux in 1.61 years at a distance of 1.64 AU in a nearly circular orbit.
In July 2014 the International Astronomical Union launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars. The process involved public nomination and voting for the new names. In December 2015, the IAU announced the winning name was Thestias for this planet. The winning name was based on that originally submitted by theSkyNet of Australia; namely Leda, Pollux's mother in Greek and Roman mythology. At the request of the IAU, 'Thestias' (the patronym of Leda, a daughter of Thestius) was substituted. This was because 'Leda' was already attributed to an asteroid and to one of Jupiter's satellites.
- Gemini in Chinese astronomy
- Cancer Minor (constellation) – Obsolete constellation inside modern Gemini
- Sudarsky's gas giant classification
- ^ NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars. IAU.org. 9 July 2014
- ^ "NameExoWorlds The Process". Archived from the original on 2015-08-15. Retrieved 2015-09-05.
- ^ Final Results of NameExoWorlds Public Vote Released, International Astronomical Union, 15 December 2015.
- ^ "NameExoWorlds The Approved Names". Archived from the original on 2018-02-01. Retrieved 2016-01-04.
- ^ YOU helped name an exoplanet!, TheSkyNet, 2015-12-17
- A. P. Hatzes; et al. (1993). "Long-period radial velocity variations in three K giants". The Astrophysical Journal. 413: 339–348. Bibcode:1993ApJ...413..339H. doi:10.1086/173002.
- A. P. Hatzes; et al. (2006). "Confirmation of the planet hypothesis for the long-period radial velocity variations of β Geminorum". Astronomy and Astrophysics. 457 (1): 335–341. arXiv:astro-ph/0606517. Bibcode:2006A&A...457..335H. doi:10.1051/0004-6361:20065445. S2CID 14319327.
- S. Reffert; et al. (2006). "Precise Radial Velocities of Giant Stars. II. Pollux and Its Planetary Companion". The Astrophysical Journal. 652 (1): 661–665. arXiv:astro-ph/0607136. Bibcode:2006ApJ...652..661R. doi:10.1086/507516. S2CID 18252884.
- Hatzes; et al. (2006-06-16). "Confirmation of the Planet Hypothesis of the Long-period Radial velocity Variations of β Geminorum" (PDF). European Southern Observatory. Archived from the original (PDF) on 2007-09-26. Retrieved 2008-06-24.
- "Pollux". SolStation. Retrieved 2005-11-21.
- Sabine Reffert; et al. (2006-07-07). "Precise Radial Velocities of Giant Stars II. Pollux and its Planetary Companion". Astrophysical Journal. 652 (1): 661–665. arXiv:astro-ph/0607136. Bibcode:2006ApJ...652..661R. doi:10.1086/507516. S2CID 18252884.