Habitable Zone Stars

Not all main-sequence stars make good homes for life. The most massive O and B stars burn through their fuel in just a few million years — not nearly long enough for complex life to evolve. Stars below about 0.5 solar masses are so dim their habitable zones are extremely close, likely causing tidal locking.

The sweet spot appears to be F, G, and K type stars, which are stable enough to last billions of years and bright enough to have habitable zones at comfortable distances. These stars make up roughly 20% of the galaxy's stellar population.