. . "Kelvin\u2013Helmholtz mechanism" . "adiabatic contraction due to cooling" . "Kelvin\u2013Helmholtz luminosity" . . "gravitational contraction" . . . "this mechanism" . . . . . "Kelvin\u2013Helmholtz timescale" . . "Kelvin\u2013Helmholtz heating" . "Kelvin\u2013Helmholtz mechanism" . . . . .