The number of potentially habitable planets is greater than previously thought, according to a new analysis by a Penn State researcher, and some of those planets are likely lurking around nearby stars.
“We now estimate that if we were to look at 10 of the nearest small stars we would find about four potentially habitable planets, give or take,” said Ravi Kopparapu, a post-doctoral researcher in geosciences. “That is a conservative estimate,” he added. “There could be more.”
Kopparapu detailed his findings in a paper accepted for publication in Astrophysical Journal Letters. In it, he recalculated the commonness of Earth-sized planets in the habitable zones of low-mass stars, also known as cool stars or M-dwarfs.
Scientists focus on M-dwarfs for several reasons, he explained. The orbit of planets around M-dwarfs is very short, which allows scientists to gather data on a greater number of orbits in a shorter period of time than can be gathered on Sun-like stars, which have larger habitable zones. M-dwarfs are also more common than stars like Earth’s Sun, which means more of them can be observed.
According to his findings, “The average distance to the nearest potentially habitable planet is about seven light years. That is about half the distance of previous estimates,” Kopparapu said. “There are about eight cool stars within 10 light-years, so conservatively, we should expect to find about three Earth-size planets in the habitable zones.”
CONTINUED at Science Daily.