Two new planets have been discovered orbiting an extremely old star; one of them could hold life.
One of the planet pair orbits the host star in the habitable zone, meaning it would be the right temperature for liquid water to exist, a Carnegie Institution news release reported.
Kapteyn's Star, which hosts the planets, is the second-fastest in the sky; it is a third of the mass of our own Sun.
The researchers used data from the HARPS spectrometer at the European Southern Observatory's La Silla observatory to look at changes in the star's motion. The Doppler Effect allowed the researchers to look at the masses and orbital periods of the planets.
"That we can make such precise measurements of such subtle effects is a real technological marvel," Jeff Crane of the Carnegie Observatories, said in the news release.
"We were surprised to find planets orbiting Kapteyn's star. Previous data showed some irregular [motion] so we were looking for very short period planets when the new signals showed up loud and clear," lead author Dr. Guillem Anglada-Escude, a former Carnegie postdoc now the Queen Mary University of London, said in the news release.
The planet, dubbed Kapteyn b, could hold water and is about five times the mass of Earth. It orbits its host star once every 48 days.
The other planet, Kapteyn c, has a year that lasts 121 days and is most likely too cold to hold liquid water.
"Finding a stable planetary system with a potentially habitable planet orbiting one of the very nearest stars in the sky is mind blowing. This is one more piece of evidence that nearly all stars have planets, and that potentially habitable planets in our Galaxy are as common as grains of sand on a beach," Pamela Arriagada, the second author, and a Carnegie postdoctoral researcher, said in the news release.
