HD 217107 c

HD 217 107 c is a Jupiter -like extrasolar planet of its star HD 217 107 orbits once every eight years. He was b identifies 2005 as the second planet according to HD 217 107 as a satellite of the star. Its mass and its orbital parameters are still not known exactly and can only be limited.

Discovery

Through measurements of the radial velocity at the star HD 217 107 1998 deviations have been found, which could be explained by the presence of a planet orbiting the star in 7.1 days. Because the planet, HD 217 107 b, but had an uncharacteristic for such planets eccentricity of its orbit, the existence of a second planet was postulated. Through long-term observations of the star a second deviation was found which had a period of 8 years, pointing to a planet that had to have at least two times the mass of Jupiter and its removal had to be at least a few astronomical units to the star. This 2005, the existence of HD 217 107 c was confirmed.

Data

HD 217 107 c has a semi-major axis of 4.41 ± 0.21 astronomical units, 0.537 ± 0.026 of an eccentricity, an orbital period of 3352 ± 157 days ( 9.18 ± 0.43 years ) and a mass greater than 2.5 ± 0.48 Jupiter masses.