We report the first disclosure of the planetary nature of Kepler-432 b ( aka Kepler object of interest KOI-1299.01 ) .
We accurately constrained its mass and eccentricity by high-precision radial velocity measurements obtained with the CAFE spectrograph at the CAHA 2.2-m telescope .
By simultaneously fitting these new data and Kepler photometry , we found that Kepler-432 b is a dense transiting exoplanet with a mass of M _ { \mathrm { p } } = 4.87 \pm 0.48 { M } _ { Jup } and radius of R _ { \mathrm { p } } = 1.120 \pm 0.036 { R } _ { Jup } .
The planet revolves every 52.5 d around a K giant star that ascends the red giant branch , and it moves on a highly eccentric orbit with e = 0.535 \pm 0.030 .
By analysing two NIR high-resolution images , we found that a star is located at 1.1 ^ { \prime \prime } from Kepler-432 , but it is too faint to cause significant effects on the transit depth .
Together with Kepler-56 and Kepler-91 , Kepler-432 occupies an almost-desert region of parameter space , which is important for constraining the evolutionary processes of planetary systems .