HD 128311 [SEP] constellation
HD 128311
HD 128311 or HN Boötis is an orange main-sequence star located approximately 54 light-years away in the constellation of Boötes. Two extrasolar planet candidates have been detected in orbit around this star.
Planetary system.
In 2002, the discovery of the planet HD 128311 b was announced by Paul Butler. In 2005, the discovery of a second planet HD 128311 c was announced by Steve Vogt.
Most likely, the system has been formed in a very turbulent disc. The authors were able
128311 b is the smaller planet, with a mass of ; it was discovered through radial velocity observations. It orbits at almost the same distance as Earth, at 1.099 AU; however, its orbital period is significantly longer at 448.6 days. 
The larger of the two, HD 128311 c, has a mass of and was discovered in the same manner. It orbits every 919 days inclined at 50°, and is 1.76 AU from the host star. The host star, HD 128311, is a K0V-type