Pollux b
{{Short description|Candidate gas giant exoplanet orbiting Pollux}}
{{Infobox planet
| name = Pollux b / Thestias
| image = Pollux b (Thestias).png
| caption = Artist's impression of Pollux b
| discoverer = Hatzes et al.
| discovery_site = United States
| discovered = 16 June 2006
| discovery_method = Radial velocity
| alt_names = β Geminorum b, HD 62509 b, Thestias
| apsis = astron
| semimajor = {{convert|1.64|±|0.27|AU|e6km|abbr=unit}}
| eccentricity = 0.02 ± 0.03
| period = 589.64 ± 0.81 d
1.61432 ± 0.00222 y
| time_periastron = 2,447,739.02 ± 4.5
| semi-amplitude = 41.0 ± 1.6
| star = Pollux
| mass = {{val|2.30|0.45|p=≥|ul=Jupiter mass}}
}}
Pollux b, formally named Thestias {{IPAc-en|'|θ|E|s|t|i|@|s}}, is an exoplanet candidate orbiting the star Pollux approximately 34 light-years away in the constellation of Gemini (the Twins). It is also designated β Geminorum b (Latinized to Beta Geminorum b, abbreviated β Gem b) or HD 62509 b. If this planet exists, it has a minimum mass of about twice the mass of Jupiter, and it moves around Pollux in 1.61 years at a distance of {{val|1.64|ul=AU|fmt=commas}} in a nearly circular orbit. However, its existence has been disputed.
History of observations
The discovery of Pollux b was announced in 2006 by astronomer Artie P. Hatzes and co-authors using the radial velocity method. A planet orbiting Pollux had previously been hypothesized by Hatzes in 1993, though at that time it was thought more likely that the radial velocity variations were caused by intrinsic stellar variability.
An independent study published shortly after the discovery paper supported the existence of Pollux b, but expressed some uncertainty, leaving a non-planetary explanation for the radial velocity variations a possibility. Another independent study in 2008 also supported the planet.
The planet's existence has been questioned by two subsequent studies, one in 2013 and its 2021 follow-up. A weak magnetic field in Pollux was detected in 2009, and it was suggested that magnetic variability in the star, as opposed to a planet, might be the cause of the observed radial velocity variations. The stellar rotation period was found to be close to the proposed period of Pollux b, casting some doubt on the planet's existence. The 2021 study monitored Pollux for 4.25 years and found the rotational period to be {{Val|660|15|u=days}}, close to Pollux b's orbital period of 590 days. Even though both values aren't equal, there might still be systematic errors in the rotational period.
Naming
In July 2014 the International Astronomical Union launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars.[http://www.iau.org/news/pressreleases/detail/iau1404/ NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars]. IAU.org. 9 July 2014 The process involved public nomination and voting for the new names.{{Cite web |url=http://nameexoworlds.iau.org/process |title=NameExoWorlds The Process |access-date=2015-09-05 |archive-date=2015-08-15 |archive-url=https://web.archive.org/web/20150815025117/http://nameexoworlds.iau.org/process |url-status=dead }} In December 2015, the IAU announced the winning name was Thestias for this planet.[http://www.iau.org/news/pressreleases/detail/iau1514/ Final Results of NameExoWorlds Public Vote Released], International Astronomical Union, 15 December 2015. 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.{{Cite web |url=http://nameexoworlds.iau.org/names |title=NameExoWorlds The Approved Names |access-date=2016-01-04 |archive-date=2018-02-01 |archive-url=https://web.archive.org/web/20180201043609/http://nameexoworlds.iau.org/names |url-status=dead }}[http://www.theskynet.org/news/67?locale=en YOU helped name an exoplanet!] {{Webarchive|url=https://web.archive.org/web/20180507155200/https://www.theskynet.org/news/67?locale=en |date=2018-05-07 }}, TheSkyNet, 2015-12-17
See also
- Gemini in Chinese astronomy
- Cancer Minor (constellation) – Obsolete constellation inside modern Gemini
- Sudarsky's gas giant classification
References
{{Reflist|refs=
{{cite journal | bibcode=1993ApJ...413..339H | author=A. P. Hatzes | display-authors=etal| title=Long-period radial velocity variations in three K giants | journal=The Astrophysical Journal | volume=413 |date=1993 | pages=339–348| doi=10.1086/173002| doi-access=free }}
{{cite journal |author=A. P. Hatzes |display-authors=etal|title=Confirmation of the planet hypothesis for the long-period radial velocity variations of β Geminorum |journal = Astronomy and Astrophysics | volume=457 | issue=1 | date=2006 | pages=335–341|doi=10.1051/0004-6361:20065445 | bibcode=2006A&A...457..335H|arxiv = astro-ph/0606517 |s2cid=14319327}}
{{cite journal | author=S. Reffert | display-authors=etal | title=Precise Radial Velocities of Giant Stars. II. Pollux and Its Planetary Companion | journal=The Astrophysical Journal | volume=652 | issue=1 | date=2006 | pages=661–665 | doi=10.1086/507516 | bibcode=2006ApJ...652..661R|arxiv = astro-ph/0607136 | s2cid=18252884 }}
{{cite journal |last1=Han |first1=In-Woo |last2=Lee |first2=Byeong-Cheol |display-authors=etal |date=June 2008 |title=Confirmation of the Exoplanet around β GEM from the RV Observations Using Boes |journal=Journal of the Korean Astronomical Society |volume=41 |issue=3 |pages=59–64 |doi=10.5303/JKAS.2008.41.3.059 |bibcode=2008JKAS...41...59H}}
{{cite journal |last1=Aurière |first1=M. |last2=Petit |first2=P. |display-authors=etal |date=February 2021 |title=Pollux: A weak dynamo-driven dipolar magnetic field and implications for its probable planet |journal=Astronomy & Astrophysics |volume=646 |issue= |pages=A130 |doi=10.1051/0004-6361/202039573 |arxiv=2101.02016 |bibcode=2021A&A...646A.130A}}
}}
External links
- {{cite web |url=http://www.solstation.com/stars2/pollux.htm |title=Pollux |access-date=2005-11-21 |work=SolStation}}
{{Sky|07|45|19.4|+|28|01|35|34}}{{Stars of Gemini}}
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Category:Gemini (constellation)
Category:Exoplanets discovered in 2006
Category:Exoplanets detected by radial velocity