c has a minimum mass of and an orbital period of 751.9 days (2.06 years). Assuming the orbits of the two are coplanar, then the two planets must be locked in a 2:1 orbital resonance, otherwise the system would become dynamically unstable. Although the inclinations from the line of sight are unknown, the value is constrained to be 70° or less: if any higher, the higher masses would render the system dynamically unstable, with no stable solutions. References K-type giants CN stars Cetus (constellation) Ceti, Eta BD–10 240 Ceti, 31 005364 0334 006805 Aoul al Naamat J01083539-1010560