Simplified Hydrostatic Carbon Burning in White Dwarf Interiors

TL;DR

This paper presents two simplified nuclear reaction networks for modeling hydrostatic carbon burning in white dwarf interiors, capturing key processes relevant to Type Ia supernova progenitors with high accuracy.

Contribution

The authors develop and validate two simplified nuclear networks that accurately approximate detailed reactions in white dwarf carbon burning, improving modeling efficiency.

Findings

N1 provides first-order ash distribution estimates.

N2 reproduces main physical properties within 5% accuracy.

Both networks effectively model Urca process effects.

Abstract

We introduce two simplified nuclear networks that can be used in hydrostatic carbon burning reactions occurring in white dwarf interiors. They model the relevant nuclear reactions in carbon-oxygen white dwarfs (COWDs) approaching ignition in Type Ia supernova (SN Ia) progenitors, including the effects of the main e-captures and \beta-decays that drive the convective Urca process. They are based on studies of a detailed nuclear network compiled by the authors and are defined by approximate sets of differential equations whose derivations are included in the text. The first network, N1, provides a good first order estimation of the distribution of ashes and it also provides a simple picture of the main reactions occurring during this phase of evolution. The second network, N2, is a more refined version of N1 and can reproduce the evolution of the main physical properties of the full network to the 5% level. We compare the evolution of the mole fraction of the relevant nuclei, the neutron excess, the photon energy generation and the neutrino losses between both simplified networks and the detailed reaction network in a fixed temperature and density parcel of gas.