Approximate and Modified Rates

For multidimensional simulation codes, it is common to approximate some rate sequences to reduce the number of nuclei while keeping the effective flows. For example, a common approximation is to combine \(A(\alpha,\gamma)B\) and \(A(\alpha,p)X(p,\gamma)\) into an effective rate and not carry nuclei \(X\) in the network.

pynucastro can do several rate approximations, as described in the next sections:

• Approximating alpha-capture
• Approximating double n-capture
• Modified Rates
• Approximating C and O Burning