An M-type star, also known as a red dwarf, is the smallest and coolest type of main-sequence star. These stars have surface temperatures ranging from about 2,400 to 3,700 Kelvin. M-type stars are the most common type of star in the universe, making up about 70-80% of all stars. They are characterized by their reddish color and low luminosity. Due to their long lifespans, which can last tens of billions of years, M-type stars often host planetary systems. Some of these stars, like Proxima Centauri, are known to have exoplanets in their habitable zones, raising interest in the search for extraterrestrial life.