Red Dwarf
<p>Jul 07, 2013 03:49 PM
 
main sequence;
 
small, relat cool but on main seq.  either late K or M
(oh, be a fine girl, kiss me) =  O B A F G K M =  spectral types from hot to cool; sun = G)
 
red dwafs range in mass from low of  0.075 solar mass (upper limit of brown dwarf) to
about 50% of the sun  and surface temp < 4,000 K.
 
red dwarfs are by far the most commontype of star in Milky Way  but cannot esily be observed.
 
Proxima Centauri is one.  as are  20 of the next nearest 30.
 
Red dwarfs make up  3/4s of stars in our galaxy.
 
Planets:  Observations with HARPS indicate  40% of red dwarfs have a superEarth planet orbiting in hab zone where water can exist.</p>