A robotic telescope detected three planets orbiting a nearby star that appear to be "super-sized Earths."
The planets were discovered by Lick Observatory's Automated Planet Finder (APF), the University of California, Berkeley reported.
"The three planets are unlike anything in our solar system, with masses seven to eight times the mass of Earth and orbits very close to their host star," said UC Berkeley graduate student Lauren Weiss.
Most planets that have been discovered outside of our solar system have been around the size of Neptune (17 times the mass of Earth) or larger, and most are gaseous. These newly-discovered planets are much smaller, and invisible to the naked eye. They were discovered through observations of their "wobble," which is created by the gravity of their host star.
"We initially used the APF like a regular telescope, staying up all night searching star to star. But the idea of letting a computer take the graveyard shift was more appealing after months of little sleep. So we wrote software to replace ourselves with a robot," said University of Hawaii at Manoa graduate student Benjamin "BJ" Fulton.
All three orbiting super-Earths at distance that is closer than Mercury orbits our own Sun, they complete their orbits in only five, 15, and 24 days. The planets are about 54 light-years away from Earth, meaning they are close enough to be considered our neighbors.
The observations of the star, dubbed HD 7924, are the beginning of a systematic survey for super-Earth planets near our own. The research will take place over a period of two years, and will hopefully produce some fascinating discoveries.
"When the survey is complete we will have a census of small planets orbiting sun-like stars within approximately 100 light-years of Earth," Fulton said.
The findings were published in a recent edition of the Astrophysical Journal.
