An ALMA large program is currently studying how anomalously top-heavy distributions of this quantity may arise from a related distribution for cores. Codes like MESA express the equation of hydrostatic equilibrium in terms of this Lagrangian coordinate. For a polytrope, this quantity is proportional to the “3 minus n over 1 minus n” power of radius. (-5[1])This quantity’s PDF was approximated as a power law with an exponent of minus 2.35 by Edwin Salpeter; that distribution (15[1])is this (15[1])quantity’s (15[2])(*) “initial function.” (10[6])A main sequence (10[1])star’s luminosity is roughly proportional to the seven-halves power of (10[1])this quantity. (10[1]-5[2])A star’s initial value of this quantity determines whether it will become a white dwarf, neutron (10[1])star, (10[1])or black (10[1])hole. (-5[1])For 10 points, Type (10[1])1a supernovae occur when a white dwarf’s value of what quantity exceeds (10[1])the Chandrasekhar (10[1])limit? ■END■ (10[6])