L-type stars are a class of cool stars that have surface temperatures between about 1,300 and 2,000 Kelvin. They are characterized by their reddish color and are often found in the brown dwarf category, which means they are not massive enough to sustain hydrogen fusion like typical stars. These stars are typically smaller than M-type stars and can be difficult to detect due to their low brightness. L-type stars often exhibit strong absorption lines in their spectra, particularly from molecules like water and methane, which helps astronomers identify them in the universe.