Masses for single stars are derived from their spectral type and
luminosity class. In addition, for double lined binaries with the secondary
component not classified, mass_binaries will compute the secondary
. Calibrations are stored in files
dwarfs.masses, spec_mass.IV, spec_mass.III, spec_mass.II, spec_mass.I
mass_stars Compute masses for stars in startable.
mass_binaries Compute secondary mass.
Function. Return mass for star with specified spectrum.