It's phrased oddly, and I haven't read the original paper; but I assume they just measured the spectra of its infrared blackbody radiation. http://en.wikipedia

It's phrased oddly, and I haven't read the original paper; but I assume they just measured the spectra of its infrared blackbody radiation. http://en.wikipedia.org/wiki/Black_body http://en.wikipedia.org/wiki/Black_body Just like how a noncontact infrared thermometer works, except you have to use a space-based telescope, due to the water in our atmosphere.