Lithium abundance is a gravitational model dependent quantity

White dwarf stars in modified gravity

“…Some shortcomings and their solutions were considered further in [86,87,88,89,90,91,92,93,94,95] while problems addressed to stability can be viewed in [69,96,97,98,99,100]. Non-relativistic stars, which are here our main concern, were discussed in [70,23,71,43,56,101,24,27].…”

“…Another important comment related to the star's age is that lithium abundance in stellar atmosphere depends on gravity model, too, introducing an additional uncertainty to age determination techniques of young stars and globular clusters since some of them rely on the lithium depletion. It was shown that in the case of Palatini f (R) gravity the age of an individual star is significantly shorter than the age in the model provided by GR [27]. Therefore, when the total star's evolution is re-analyzed, it will very probably happen that the age of the KIC 8145411 white dwarf lies in the reasonable range.…”

“…The lifetime of a main sequence star as well as the cooling time of white dwarfs (taking into account the crystallization process) are quantities which depend on the luminosity and mass of the stars [20]. It was shown [21,22,23,24,27,28] that in the case of some gravitational theories both mass and luminosity change because they are sensitive to modifications of Einstein's gravity. Indeed, although white dwarfs can be treated by the Newtonian hydrostatic equilibrium equation, which is used in the computations of the lifetime of the main sequence stars and cooling processes, many theories of gravity modify that equation (see e.g.…”