  A simple cooling model of white dwarf stars is re-analyzed in Palatini $f(R)$
gravity. Modified gravity affects the white dwarf structures and consequently
their ages. We find that the resulting super-Chandrasekhar white dwarfs need
more time to cool down than sub-Chandrasekhar ones, or when compared to the
Newtonian models.

General Relativity and Quantum Cosmology;High Energy Astrophysical Phenomena;Solar and Stellar Astrophysics