K-type stars are very stable for most of their lives. That’s why they may be the best stars to study in search for life.
K-type stars are stable in the main sequence phase for a very long time — 20 to 70 billion years, compared to 10 billion for the Sun.
So, orange dwarfs have stable habitable zones that offer a long period for life’s development and are less likely to send out damaging X-rays and ultraviolet radiation.
Observations show that K-type stars are three times more abundant than stars of our type and more abundant stars means more chances at life.
These stars are also relatively easy targets for finding planets. That’s because the light of such stars is slightly dimmer than the Sun’s, making planets more easily visible as they pass in front of their star.
Also, an orange star has a smaller mass than a sun-like star meaning it has a bigger gravitational wobble as it gets tugged on by an orbiting planet.
K-type stars appear orange in color, but, like most stars, are white.
Two well-known examples are Epsilon Eridani and Alpha Centauri B.
The luminosity of such stars is approximately between 10% and 50% of that generated by our sun. They are also a little less massive than our star, having between 50% and 80% the mass of the sun.
Orange dwarfs change very little in brightness compared to sun-like stars.
Our own sun has brightened by about 30% since the solar system began, and will likely make Earth too hot for life in about 1 billion years.
While there’s still a lot that scientists don’t know when it comes to K-type stars at this point, current data certainly points to some very helpful insights that could make them worthy contenders of sustainable life in the future.