Under a Crimson Sun

Prospects for Life in a Red Dwarf System

David S Stevenson, Springer, MultCo 576.839S8474U 2013


A book about the prospects of life on planets around M and L stars.

Spectral class, hot to cold: O B A F G K M L : Oh Be A Fine (Girl/Guy) Kiss My Lips

O through F are very big, bright, and fast burning. Probably evolving too rapidly for intelligent life to emerge.

There are twice as many K stars as G stars, and far more M's and L's - some of the L's may be too difficult to detect, or have not yet ignited in 14 billion years. Are the coldest too unenergetic to power aerobic oxygen-generating photosynthesis?

Less luminous stars last far longer - and planets can orbit closer in. Too close in, and they tide-lock one face towards the star.