A team of astronomers has made two discoveries: a super-Earth sitting a mere 42 light years away at just the right temperature for liquid water -- and a creative new way to look for such exoplanets.
The super-Earth, HD 40307-g, is one of three discovered around HD 40307, bringing the grand total of planets around the dwarf star up to six. It lies in what's known as the habitable zone, where liquid water -- a required ingredient for life -- could exist. At seven Earth masses, it's likely hefty enough to have an atmosphere, said study co-author Hugh Jones, a University of Hertfordshire astronomer. And it's far enough away from its star that it should rotate freely, giving it a proper night and day.
The research, released Wednesday by the journal Astronomy & Astrophysics, used a novel technique to analyze existing measurements of a nearby star -- one that looks only at the "red" half of a star's light and ignores the "blue" half.
"The real exciting result was they were able to take data from the archive, which we knew was good, and make it better," said Eric Ford, an astronomer at the University of Florida in Gainesville who was not involved in the study.
The method could influence how future planet-hunting instruments are built, Ford said. And it could mean that there are even more planets just waiting to be found, hidden in old measurements.
If confirmed, this massive planet would be far closer than Kepler 22-b, the first planet discovered in the habitable zone, which lies some 600 light years away. But the find is stirring up scientists back on Earth, a reminder of the perils of planet-hunting.