18 Delphini
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Delphinus |
| Right ascension | 20h 58m 25.93s |
| Declination | +10° 50' 21.43″ |
| Apparent magnitude (V) | 5.522 |
| Absolute magnitude (V) | 1.202 |
| Distance | 238.493 ly (73.121 pc) |
| Spectral type | G6III: |
| Other designations | |
| Database references | |
| SIMBAD | data |
18 Delphini (abbreviated 18 Del), also named Musica,[1] is a yellow giant star of spectral type G6III situated approximately 238 light-years from Earth in the constellation of Delphinus. An extrasolar planet (designated 18 Delphini b, later named Arion) is believed to be orbiting the star.
Nomenclature
18 Delphini is the star's Flamsteed designation. Following its discovery the planet was designated 18 Delphini b.[2]
In July 2014 the International Astronomical Union launched 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 winning names were Musica for this star and Arion for its planet.[5]
The winning names were those submitted by the Tokushima Prefectural Jonan High School Science Club of Japan. 'Musica' is Latin for 'music'. 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').
In 2016, the IAU organized a Working Group on Star Names (WGSN)[7] to catalog and standardize proper names for stars. In its first bulletin of July 2016,[8] the WGSN explicitly recognized the names of exoplanets and their host stars approved by the Executive Committee Working Group Public Naming of Planets and Planetary Satellites, including the names of stars adopted during the 2015 NameExoWorlds campaign. This star is now so entered in the IAU Catalog of Star Names.[1]
Planetary system
On February 19, 2008, a 10.3 Jupiter mass extrasolar planet was found to be orbiting the star.[2]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (Arion) | >10.3 MJ | 2.6 | 993.3 ± 3.2 | 0.08 ± 0.01 | — | — |
References
- 1 2 "IAU Catalog of Star Names". Retrieved 28 July 2016.
- 1 2 3 Sato, Bun'ei; et al. (2008). "Planetary Companions around Three Intermediate-Mass G and K Giants: 18 Delphini, ξ Aquilae and HD 81688". Publications of the Astronomical Society of Japan. 60 (3): 539–550. arXiv:0802.2590
. Bibcode:2008PASJ...60..539S. doi:10.1093/pasj/60.3.539. - ↑ NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars. IAU.org. 9 July 2014
- ↑ NameExoWorlds The Process
- ↑ Final Results of NameExoWorlds Public Vote Released, International Astronomical Union, 15 December 2015.
- ↑ NameExoWorlds The Approved Names
- ↑ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
- ↑ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
External links
- Jean Schneider (2011). "Notes for star 18 Del". Extrasolar Planets Encyclopaedia. Retrieved 30 September 2011.
Coordinates: 
20h 58m 26s, +10° 50′ 21″