K dwarfs, on the other hand, don’t give off so much dangerous radiation. A group of researchers including Edward Guinan, an astronomer at Villanova University in Pennsylvania, found that planets orbiting K dwarfs would probably only get bombarded by one-hundredth the X-ray radiation that planets around M dwarfs would receive.
A goldilocks star
The team also points out that K dwarfs have the added benefit of a longer stable lifetime than G-type stars like the sun.
“There’s nothing wrong with a G star,” Guinan said during a press conference. “They just don’t live too long.”
Stars like our sun spend about 10 billion years in the stable, “main sequence” phases of their lives before ballooning into red giants. But K dwarfs can live for 15 to 45 billion years before growing into red giants, giving planets around them much more time to potentially evolve life and then to keep living things around for longer.
This combination of long life, relatively large numbers and low levels of dangerous radiation make K dwarfs a kind of “Goldilocks” star for researchers searching for extraterrestrial life, the researchers say.