Speaker
Gilles Fontaine
(Université de Montréal)
Description
White dwarf cosmochronology has yet to reach its full potential due to recurrent uncertainties associated with the constitutive physics of warm dense matter. For instance, radiative opacities still need to be extrapolated in cool white dwarf models. In addition, cooling ages depend sensitively on the internal chemical stratification which is shaped, over time, by the still uncertain rate of the C12(alpha,gamma)O16 reaction, by convection, semi-convection, overshooting, other mixing processes such as rotational mixing, and by thermal pulses that occur primarily on the Asymptotic Giant Branch. All of these suffer notoriously from major uncertainties, which undermine the reliability of white dwarf cosmochronology. I will review where we stand on these questions, including some very recent seismic results which should lead to an eventual empirical "calibration" of the internal chemical profile of white dwarf stars and, hence, contribute to making white dwarf cooling ages more reliable.
Primary author
Gilles Fontaine
(Université de Montréal)
