Computer models predict Gliese 581 C is either a rocky planet like Earth or a waterworld covered entirely by oceans.
We have estimated that the mean temperature of this super-Earth lies between 0 and 40 degrees Celsius [32 to 104 degrees Fahrenheit], and water would thus be liquid, Udry said.
The scientists discovered the new world using the HARP instrument on the European Southern Observatory 3.6 meter telescope in La Sille, Chile. They employed the so-called radial velocity, or wobble, technique, in which the size and mass of a planet are determined based on small perturbations it induces in its parent stars orbit via gravity.
Udry said there was a fair amount of time between the calculation of Gliese 581 Cs size and the realization it was within its stars habitable zone. That came at the end, Udry said.
When it did hit him, Udry knew he would be spending time fielding phone calls from the media. You right away think about the journalists who will like it very much, he told SPACE.com.