Other Scientists Disagree!

♦ Erroneous data analysis ♦

In December 2010, a methodological error has been revealed in the data analysis that lead to the "discovery" of Gliese 581 f and g.[13] The team around Steven Vogt inferred the number of exoplanets by using a reduced chi-square, although the orbital models are nonlinear in the model parameters. Therefore, reduced chi-square is not a trustworthy diagnostic. In fact, an investigation of the fit residuals showed that the data used by Vogt's team actually prefers a model with four planets, not six, in agreement with the results of Francesco Pepe's team.

[edit] Further analyses of HIRES/HARPS dataAnother re-analysis found no clear evidence for a fifth planetary signal in the combined HIRES/HARPS data set.[14] The claim was made that the HARPS data only provided some evidence for 5 planet signals, while incorporation of both data sets actually degraded the evidence for more than four planets (i.e., none for 581 f or 581 g).

"I have studied [the paper] in detail and do not agree with his conclusions,"[15] Steven Vogt said in reply, concerned that Gregory has considered the HIRES data as more uncertain.[16] The question of Gliese 581g's existence won't be settled definitively until researchers gather more high-precision radial velocity data, Vogt said.
♦(http://en.wikipedia.org/wiki/Gliese_581_g#Erroneous_data_analysis )