Anisotropic magnetized white dwarfs: Unifying under- and over-luminous peculiar and standard type Ia supernovae

TL;DR

This paper investigates how strong magnetic fields and anisotropy in white dwarfs can explain the diverse luminosities of type Ia supernovae, challenging the traditional Chandrasekhar mass limit as a universal standard.

Contribution

It demonstrates that magnetic field effects and anisotropy in white dwarfs can produce a range of mass limits, unifying explanations for both under- and over-luminous supernovae.

Findings

White dwarf properties are significantly affected by magnetic fields and anisotropy.

Mass-radius relations can exceed or fall below the Chandrasekhar limit.

Implications for using white dwarfs as standard candles in cosmology.

Abstract

Ever since the observation of peculiar over-luminous type Ia supernovae (SNeIa), exploring possible violations of the canonical Chandrasekhar mass-limit (CML) has become a pressing research area of modern astrophysics. Since its first detection in 2003, more than a dozen of peculiar over-luminous SNeIa has been detected, but the true nature of the underlying progenitors is still under dispute. Furthermore, there are also under-luminous SNeIa whose progenitor masses appear to be well below the CML (sub-Chandrasekhar progenitors). These observations call into question how sacrosanct the CML is. We have shown recently in Paper I that the presence of a strong magnetic field, the anisotropy of dense matter, as well as the orientation of the magnetic field itself significantly influence the properties of neutron and quark stars. Here, we study these effects for white dwarfs, which shows that their properties are also severely impacted. Most importantly, we arrive at a variety of mass-radius relations of white dwarfs which accommodate sub- to super-Chandrasekhar mass limits. This urges caution when using white dwarfs associated with SNeIa as standard candles.