18 Delphini b
Extrasolar planet in the constellation Delphinus
From Wikipedia, the free encyclopedia
18 Delphini b (abbreviated 18 Del b), formally named Arion /ÉËraɪÉn/,[2] is an extrasolar planet approximately 245 light-years away in the constellation of Delphinus.[3]
 Radial velocity changes over time of 18 Delphini caused by the orbit of 18 Delphini b. | |
| Discovery | |
|---|---|
| Discovered by | Sato et al.[1] |
| Discovery site | Okayama Planet Search Program  Japan |
| Discovery date | 19 February 2008 |
| radial velocity | |
| Orbital characteristics | |
| 2.476 AU (370,400,000 km) | |
| Eccentricity | 0.08 ± 0.01 |
| 993.3 ± 3.2 d 2.719 y | |
| 2451672 ± 18 | |
| 166.1 ± 6.5 | |
| Star | 18 Delphini |
| Physical characteristics | |
| Mass | 9.207 |
The 993-day period planet orbits the Red clump star 18 Delphini 2.476 AU away every 2.719 years. It is a very massive and dense planet with a mass of 9.207 MJ, it was discovered on February 19, 2008, by Bun'ei Sato.[4][1]
In July 2014, the International Astronomical Union launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars.[5] The process involved public nomination and voting for the new names.[6] In December 2015, the IAU announced the name Arion for this planet.[7] 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[8] ('Delphinus' is Latin for 'dolphin').
