where T c and ρ ρ are the mid-plane temperature and density respectively. M ˙ ˙ 16 is the accretion rate, in units of 10 16 g s − − 1 , m 1 is the mass of the central accreting object in units of a solar mass, M ⨀ ⨀ , R 10 is the radius of a point in the disk, in units of 10 10 c m , and f = [ 1 − − ( R ⋆ ⋆ R ) 1 / 2 ] 1 / 4 , where R ⋆ ⋆ is the radius where angular momentum stops being transported inward.