M Stars are a type of star classified by their low temperature and small size. They are the coolest and dimmest stars on the main sequence, with surface temperatures below 3,500 Kelvin. M Stars are often red in color and can be found in various stages of their life cycle, from young to old. These stars are significant in the study of exoplanets because they have stable environments that can support planetary systems. Many M Stars are known to host Earth-like planets, making them prime targets for the search for extraterrestrial life.