If a mass figure for a galaxy is labeled $M_*$, what component does that figure represent?

Answer

Mass locked up in stars and gas derived from light modeling.

$M_*$ refers specifically to the stellar mass, which is estimated by measuring total light output (luminosity) and applying an assumed Mass-to-Light ratio.

If a mass figure for a galaxy is labeled $M_*$, what component does that figure represent?
physicsmeasurementgalaxyastronomymass