 Differences in the two groups ' results may involve the planetary orbital characteristics assumed in calculations . According to MIT astronomer Sara Seager , Vogt postulated the planets around Gliese 581 had perfectly circular orbits whereas the Swiss group thought the orbits were more eccentric . This difference in approach may be the reason for the disagreement , according to Alan Boss . Butler remarked that with additional observations , " I would expect that on the time scale of a year or two this should be settled . " Other astronomers also supported a deliberate evaluation : Seager stated , " We will have consensus at some point ; I don 't think we need to vote right now . " and Ray Jayawardhana noted , " Given the extremely interesting implications of such a discovery , it 's important to have independent confirmation . " Gliese 581 g is listed as " unconfirmed " in the Extrasolar Planets Encyclopaedia . 
