This leads to a rapid increase in maximum density (Figure \[bate.rotmassdens\]) as angular momentum is removed from the central regions of the first core (now a disc with spiral structure) by gravitational torques ($t=1.023-1.030~t_{\rm ff}$). An MPEG animation of this bar instability is provided on this CD-ROM (bate1.mpg). When the maximum temperature reaches 2000 K, molecular hydrogen begins to dissociate, resulting in a rapid second collapse to stellar densities ($t=1.030~t_{\rm ff}$). The collapse is again halted at a density of $\approx 0.007$ g cm$^{-3}$ with the formation of the second hydrostatic, or stellar, core. The initial mass and radius of the stellar core are $\approx 0.0015 {\rm \ M}_\odot$ ($\approx 5 \times 10^2$ particles) and $\approx 0.8 {\rm \ R}_\odot$, respectively. Finally, an inner circumstellar disc begins to form around the stellar object, within the region undergoing second collapse. The calculation is stopped when the stellar object has a mass of $\approx 0.004 {\rm \ M}_\odot$ ($\approx 1.2 \times 10^3$ particles), the inner circumstellar disc has extended out to $\approx 0.1$ AU, and the outer disc (the remnant of the first hydrostatic core) contains $\approx 0.08 {\rm \ M}_\odot$ ($\approx 2.4 \times 10^4$ particles) and extends out to $\approx 70$ 