18 Delphini b (abbreviated 18 Del b), formally named Arion /əˈraɪən/,[2] is an extrasolar planet approximately 249 light-years away in the constellation of Delphinus.
Discovery | |
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Discovered by | Sato et al.[1] |
Discovery site | Okayama Planet Search Program ![]() |
Discovery date | 19 February 2008 |
Detection method | radial velocity |
Orbital characteristics | |
Semi-major axis | 2.6 AU (390,000,000 km) |
Eccentricity | 0.08 ± 0.01 |
Orbital period (sidereal) | 993.3 ± 3.2 d 2.719 y |
Time of periastron | 2451672 ± 18 |
Argument of periastron | 166.1 ± 6.5 |
The 993-day period planet orbits the yellow giant star 18 Delphini. A very massive and dense planet with a minimum mass of 10.3 MJ, it was discovered on February 19, 2008, by Bun'ei Sato.[1]
In July 2014, the International Astronomical Union launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars.[3] The process involved public nomination and voting for the new names.[4] In December 2015, the IAU announced the name Arion for this planet.[5] The winning name was submitted by the Tokushima Prefectural Jonan High School Science Club of Japan. Arion was a genius of poetry and music in ancient Greece. According to legend, his life was saved at sea by dolphins after attracting their attention by the playing of his kithara[6] ('Delphinus' is Latin for 'dolphin').
Constellation of Delphinus | |||||||||||||
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