M-dwarfs, also known as red dwarfs, are the smallest and coolest type of star in the main sequence category. They have a mass between about 0.08 and 0.6 times that of the Sun and emit less light and heat. Due to their low temperature, they appear red in color and can burn for billions of years, making them the most common type of star in the Milky Way galaxy. These stars are of great interest in the search for extraterrestrial life because many have planets in their habitable zones. Their long lifespans provide a stable environment for potential life to develop, making M-dwarfs key targets for exoplanet research.