MESA Models of Classical Nova Outbursts: The Multicycle Evolution and Effects of Convective Boundary Mixing

TL;DR

This study uses the MESA code to model multicycle classical nova outbursts on CO white dwarfs, examining effects of accretion, mixing, and nuclear physics to better understand nova diversity and improve simulation accuracy.

Contribution

It introduces detailed multicycle nova models with convective boundary mixing, exploring various parameters and comparing results to observations and previous studies.

Findings

Convective boundary mixing enriches the envelope with C and O, matching observations.

Models show dependence of nova outbursts on WD mass, accretion rate, and cooling time.

A new 3He-triggered convection scenario is proposed.

Abstract

Novae are cataclysmic variables driven by accretion of H-rich material onto a white-dwarf (WD) star from its low-mass main-sequence binary companion. New time-domain observational capabilities, such as the Palomar Transient Factory and Pan-STARRS, have revealed a diversity of their behaviour that should be theoretically addressed. Nova outbursts depend sensitively on nuclear physics data, and more readily available nova simulations are needed in order to effectively prioritize experimental effort in nuclear astrophysics. In this paper we use the MESA stellar evolution code to construct multicycle nova evolution sequences with CO WD cores. We explore a range of WD masses and accretion rates as well as the effect of different cooling times before the onset of accretion. In addition, we study the dependence on the elemental abundance distribution of accreted material and convective boundary mixing at the core-envelope interface. Models with such convective boundary mixing display an enrichment of the accreted envelope with C and O from the underlying white dwarf that is commensurate with observations. We compare our results with the previous work and investigate a new scenario for novae with the 3He-triggered convection.