An M-type star, also known as a red dwarf, is the smallest and coolest type of main-sequence star. These stars have a surface temperature of less than 3,500 Kelvin and are characterized by their reddish hue. M-type stars make up about 70-80% of the stars in the universe, and they are known for their long lifespans, often lasting tens of billions of years. Due to their low brightness, M-type stars are often difficult to observe from Earth. However, they can host planetary systems, and some of these planets may lie within the habitable zone, where conditions could support liquid water. This makes M-type stars of great interest in the search for extraterrestrial life.