Task: Text Categorization
Input (English): The incremental distributional value of this quantity for a given sliver of the mass distribution of stars can be found from the Schecter function. For main sequence stars, this value is approximately proportional to the 3. 9th power of the star's mass, and one law for calculating this quantity sets it proportional to the fourth power of the stellar velocity dispersion; that law only applies to elliptical galaxies. For a spiral galaxy can be found from the amplitude of its rotation curve in the Tully-Fisher relation. Often calculated for a blackbody by multiplying 4 pi r squared times the result of the Stefan-Boltzmann law, for 10 points, name this quantity, which is equal to the energy radiated by an astronomical body per unit time.
Output (English): Science