Type L star

Type L dwarfs get their designation because they are cooler than M stars and L is the remaining letter alphabetically closest to M. L does not mean lithium dwarf; a large fraction of these stars do not have lithium in their spectra. Some of those objects have masses large enough to support hydrogen fusion, but some are of substellar mass and do not, so collectively these objects should be referred to as L dwarfs, not L stars. They are a very dark red in color and brightest in infrared. Their atmosphere is cool enough to allow metal hybrides and alkali metals to be prominent in their spectra. Due to low gravities in giant stars, TiO- and VO-bearing condensates never form. Thus, larger L-type stars can never form in an isolated environment. It may be possible for these L-type supergiants to form through stellar collision, however, an example of which is V838 Monocerotis.

Other examples include VW Hyi, 2MASS J0746425plus2000321 system, and the LSR 1610-0040 subdwarf.