For simulations of gravitational fragmentation in the outer regions of a massive circumstellar disc, the reader is referred to Stamatellos et al. (2007a).

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In the inner parts of the disc, the ratio of specific heats decreases from $\gamma\simeq 5/3$ to $\gamma\simeq 7/5$ , due to the increasing temperature and the resulting excitation of the rotational degrees of freedom of H_₂. Consequently the maximum value of $t_{_{\rm COOL}}$ for fragmentation increases to $\sim$ $2 t_{_{\rm ORB}}$ (e.g. Johnson & Gammie 2003; Rice et al. 2005).

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... radius

Note also that Boley et al. use the adiabatic sound speed to calculate Q, and hence their Q-values are increased by a factor $\gamma^{1/2}\sim 1.3$ relative to ours.

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