Their small size (from 0.1 to 0.6 solar masses) means that their nuclear reactions proceed exceptionally slowly, and they emit very little light (from 3% of that produced by the Sun to as little as 0.01%).
=== Sistemi rdečih pritlikavk ===Določanje naseljivosti planetov v sistemih rdečih pritlikavk lahko pomaga določiti kako razširjeno je lahko življenje v Vesolju, ker je delež rdečih pritlikavk med 70 do 90 % vseh zvezd v galaksiji.