  Intrinsic sequences of luminosity V and III stars in the J-H vs. H-Ks diagram
of the 2MASS system are determined using about 1250 unreddened and dereddened
stars. Intrinsic color indices for MK spectral classes are tabulated and
compared with the results in other JHK systems.

Solar and Stellar Astrophysics;Astrophysics of Galaxies