Task: Text Categorization
Input (English): Tremonti et al. used the results from SDSS to derive the relation named for this quantity and stellar metallicity. This quantity is related to the velocity dispersion in a different relation named for it and the Greek letter sigma. Wolf-Rayet stars are defined by their quick changes in this value. The temperature and density variables were used by Jeans to create an upper bound on this quantity for a molecular cloud. The (*) lifetime of a main sequence star is proportional to this quantity raised to the minus 2.5 power, or alternatively this quantity divided by the luminosity. A star possessing a stellar wind is currently lowering its value for this quantity. For 10 points, name this quantity that appears along with the radius and "big G" in Newton's law of gravitation.
Output (English): Science