# example_astero¶

An example optimisation run of the astero module, based on the CoRoT target HD 49385. This is the usual starting point if you want to optimise model parameters using the astero module. This test case was introduced in Sec. 3.2 of MESA II and uses the observational constraints presented by Deheuvels et al. (2010) and analysed by Deheuvels & Michel (2011). The test uses the effective temperature, metallicity and mode frequencies of angular degree 0, 1 and 2.

For speed, the test case only runs the initial parameters set by first_*. To optimse the model parameters, change search_type to one of the search options.

The test fails if the total $$\chi^2$$ is not between 1 and 15. Mode frequencies are quite sensitive to microphysics like opacity tables, nuclear reaction rates and the equation of state, so changes to those modules can eventually push $$\chi^2$$ above 15, triggering failure. This is usually resolved by re-optimising the model.

If $$\chi^2$$ is smaller than zero, then $$\chi^2$$ was never successfully evaluated. The only possible negative value should be the placeholder initial value of -1.

Finally, if $$\chi^2$$ is between zero and one, the test fails because that sounds too good to be true!

Last-Update: 2020-11-13 (mesa r14889) by Warrick Ball