 It is estimated that the average global equilibrium temperature ( the temperature in the absence of atmospheric effects ) of Gliese 581 g would range from 209 to 228 K ( − 64 to − 45 ° C , or − 84 to − 49 ° F ) for Bond albedos ( reflectivities ) from 0 @.@ 5 to 0 @.@ 3 ( with the latter being more characteristic of the inner Solar System ) . Adding an Earth @-@ like greenhouse effect would yield an average surface temperature in the range of 236 to 261 K ( − 37 to − 12 ° C , or − 35 to 10 ° F ) . Gliese 581g would be in an orbit where a silicate weathering thermostat could operate , and this could lead to accumulation of sufficient carbon dioxide in the atmosphere to permit liquid water to exist at the surface , provided the planet 's composition and tectonic behavior could support sustained outgassing . 
