New Delhi, July 3 -- AUSTIN - The evidence that GJ 3378b might support life is thin. The evidence that it cannot is thinner still. That ambiguity, not the planet itself, is why a team from McDonald Observatory spent two years reangling its spectrometers at a dim red star 25 light-years from Earth.

The team, led by astronomer Paul Robertson, has revised the estimated mass of GJ 3378b, a super-Earth orbiting the star GJ 3378, from 5.26 Earth masses down to 2.3 Earth masses. The reduction, described in a study submitted to the preprint server arXiv in May, shifts the planet from the ambiguous territory between rocky worlds and sub-Neptune gas balls toward the range where a solid surface, and theoretically liquid water, become plausible.

Th...