HD 217107 b
| Discovery | |
|---|---|
| Discovered by | Marcy et al. |
| Discovery site | United States |
| Discovery date | November 24, 1998 |
| Doppler spectroscopy | |
| Orbital characteristics | |
| 0.07505±0.00097 AU | |
| Eccentricity | 0.1283±0.0027[1] |
| 7.126846±0.000013[1] d | |
| 2454395.789±0.025[1] | |
| 24.0±1.3[1] | |
| Semi-amplitude | 140.30±0.40[1] |
| Star | HD 217107 |
HD 217107 b is an extrasolar planet[2] approximately 65 light-years away from Earth in the constellation of Pisces (the Fish). The planet was discovered orbiting the star HD 217107 approximately every seven days, classifying the planet as a hot Jupiter. Because of the planet's somewhat eccentric orbit, scientists were able to confirm another planet within the system (HD 217107 c).
Discovery
[edit]It was found by detecting small variations in the radial velocity of the star it orbits, caused by the tug of its gravity. A study of the radial velocity of HD 217107 carried out in 1998 revealed that its motion along the line of sight varied over a 7.1 day cycle. The period and amplitude of this variation indicated that it was caused by a planetary companion in orbit around the star, with a minimum mass slightly greater than that of Jupiter.[3] The planet's mean distance from the star is less than one fifth of Mercury's distance from the Sun.
Indication of second planet
[edit]While most planets with orbital periods of less than 10 days have almost circular orbits, HD 217107 b has a somewhat eccentric orbit, and its discoverers hypothesized that this could be due to the gravitational influence of a second planet in the system at a distance of several astronomical units (AU).[4] Confirmation of the existence of a second planet, HD 217107 c, followed in 2005.
See also
[edit]References
[edit]- ^ a b c d e Feng, Y. Katherina; et al. (2015). "The California Planet Survey IV: A Planet Orbiting the Giant Star HD 145934 and Updates to Seven Systems with Long-period Planets". The Astrophysical Journal. 800 (1). 22. arXiv:1501.00633. Bibcode:2015ApJ...800...22F. doi:10.1088/0004-637X/800/1/22. S2CID 56390823.
- ^ Vogt, Steven S.; et al. (2005). "Five New Multicomponent Planetary Systems" (PDF). The Astrophysical Journal. 632 (1): 638–658. Bibcode:2005ApJ...632..638V. doi:10.1086/432901. S2CID 16509245.
- ^ Fischer, Debra A.; et al. (1999). "Planetary Companions around Two Solar-Type Stars: HD 195019 and HD 217107". Publications of the Astronomical Society of the Pacific. 111 (755): 50–56. arXiv:astro-ph/9810420. Bibcode:1999PASP..111...50F. doi:10.1086/316304. S2CID 17980987.
- ^ Fischer, Debra A.; et al. (2002). "Planetary Companions to HD 12661, HD 92788, and HD 38529 and Variations in Keplerian Residuals of Extrasolar Planets". The Astrophysical Journal. 551 (2): 1107–1118. Bibcode:2001ApJ...551.1107F. doi:10.1086/320224.
External links
[edit]- "HD 217107 / HR 8734". SolStation. Retrieved 2008-06-23.
- "Notes for planet HD 217107 b". Extrasolar Planets Encyclopaedia. Retrieved 2008-06-23.
