M dwarfs, also known as red dwarfs, are the smallest and coolest type of main-sequence stars. They have a mass between about 0.08 and 0.6 times that of the Sun, making them much less luminous. Due to their low temperature, they emit most of their light in the infrared spectrum. M dwarfs are the most common type of star in the universe, accounting for about 70-80% of all stars. These stars have long lifespans, often lasting tens of billions of years, which allows them to host stable planetary systems. Many exoplanets have been discovered orbiting M dwarfs, making them prime targets in the search for extraterrestrial life. Their dimness and longevity make them interesting objects of study in astronomy.