M-Type stars, also known as M dwarfs, are the smallest and coolest type of main-sequence stars in the Hertzsprung-Russell diagram. They have surface temperatures ranging from about 2,400 to 3,700 Kelvin and are often red in color due to their low temperature. M-Type stars are the most common type of star in the universe, making up about 70% of all stars. These stars have a long lifespan, often lasting tens of billions of years, which allows them to host stable planetary systems. Many exoplanets have been discovered orbiting M-Type stars, making them prime targets in the search for extraterrestrial life.