A new synthetic model for asymptotic giant branch stars

We present a synthetic model for thermally pulsing asymptotic giant branch (TPAGB) evolution constructed by fitting expressions to full evolutionary models in the metallicity range 0.0001 ≤Z≤ 0.02. Our model includes parametrizations of third dredge-up and hot-bottom burning with mass and metallicity. The Large Magellanic Cloud and Small Magellanic Cloud carbon star luminosity functions are used to calibrate third dredge-up. We calculate yields appropriate for galactic chemical evolution models for ¹H, ⁴He, ¹²C, ¹³C, ¹⁴N, ¹⁵N, ¹⁶O and ¹⁷O. The initial-final mass relation is examined for our stars and found to fit to within 0.1 M_⊙ of the observations. We also reproduce well the white dwarf mass function for masses above about 0.58 M_⊙. The new model is to be implemented in a rapid binary star evolution code.