HD 155358 b has mass little bit less than Jupiter but more than Saturn. HD 155358 c has 0.8 the mass of Jupiter. HD 155358 b orbits at 0.64 AU while c orbits at 1.02 AU.
On 10 May 2007, astronomers included Cochran from the University of Texas announced two mass type II planets orbiting the same star with the lowest metal content than any planetary host stars. Its discoveries were made by using the Hobby-Eberly Telescope, which used radial velocity to monitor the change of line of sight motion of the star caused by gravity of the planets. These two planets gravitationally interact: modelling the planets assuming their masses are the same as the empirically-determined lower limits, they exchange eccentricities on a timescale of 2700 years, and their arguments of periastron precess on a timescale of 2300 years.