sentences:  Because Gliese 581d was believed to orbit outside the habitable zone of its star it was originally thought to be too cold for liquid water to be present.With the 2009 revised orbit, climate simulations
  conducted by researchers in France in 2011 indicated possible temperatures suitable for surface water at sufficient atmospheric pressure According to Stéphane Udry, "It could be covered by a 'large and deep ocean'; it is the first serious ocean planet candidate.