HD 217107 b

HD 217 107 b is an extrasolar planet orbiting the Sun-like star 217 107 HD every 7.1 days. He is the innermost known star of its planetary system and was discovered by the California and Carnegie Planet Search Team. Due to its size and proximity to the central star, the planet is the type of "hot Jupiter" attributed.

Discovery

Like most exoplanets found by measurements of the radial velocity and HD 217 107 b. In the radial velocity small fluctuations with a period of 7.1 days were observed. The period and amplitude of the deviation indicated a relatively large companion that orbits the star in just 7.1 days this. Computational models revealed a mass for HD 217 107 b, which is only slightly larger than that of Jupiter, perfect.

It has been shown that the semi-major axis of the planet is 0.074 (± 0.002 ) AU. The eccentricity of the orbital ellipse is 0.13 ( / - 0.02), the orbital period 7.1269 (± 0.00022 ) days, the mass of the planet is limited to the range of 1.37 (± 0.14) Jupiter masses.

Note on the second planet

Planets that orbit so close to their sun, usually have very circular orbits. Therefore, the eccentricity of HD 217 107 b found pointed to the presence of a second planet with a relatively great distance from the star. Through long-term observation of the star HD 217 107 was the existence of a second planet, HD 217 107 c, to be confirmed in 2005.