Imprint of modified Einstein's gravity on white dwarfs: Unifying type Ia supernovae

TL;DR

This paper explores how modified Einstein's gravity affects white dwarf stars, potentially explaining the diversity in type Ia supernovae luminosities and challenging the universality of Chandrasekhar's limit.

Contribution

It demonstrates that modified gravity can produce white dwarfs with varying limiting masses, unifying under- and over-luminous supernovae phenomena.

Findings

Modified gravity induces sub- and super-Chandrasekhar white dwarfs.

Explains under- and over-luminous type Ia supernovae.

Challenges the universality of Chandrasekhar's limit.

Abstract

We establish the importance of modified Einstein's gravity (MG) in white dwarfs (WDs) for the first time in the literature. We show that MG leads to significantly sub- and super-Chandrasekhar limiting mass WDs, depending on a single model parameter. However, conventional WDs on approaching Chandrasekhar's limit are expected to trigger type Ia supernovae (SNeIa), a key to unravel the evolutionary history of the universe. Nevertheless, observations of several peculiar, under- and over-luminous SNeIa argue for the limiting mass widely different from Chandrasekhar's limit. Explosions of MG induced sub- and super-Chandrasekhar limiting mass WDs explain under- and over-luminous SNeIa respectively, thus unifying these two apparently disjoint sub-classes. Our discovery questions both the global validity of Einstein's gravity and the uniqueness of Chandrasekhar's limit.