Calcium Excess in Novae: Beyond Nuclear Physics Uncertainties

Fuente: arXiv
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Autori principali: Loria, Mallory, Denissenkov, Pavel, Ruiz, Chris, Herwig, Falk
Natura: Preprint
Pubblicazione: 2025
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author Loria, Mallory
Denissenkov, Pavel
Ruiz, Chris
Herwig, Falk
author_facet Loria, Mallory
Denissenkov, Pavel
Ruiz, Chris
Herwig, Falk
contents We examine Ca abundances in classical novae from spectroscopic observations spanning 65 years and investigate whether they are systematically high compared to those predicted by nova models. For the first time, we perform Monte Carlo simulations assessing the impact of nuclear reaction rate uncertainties on abundances predicted by multi-zone nova models. While the Ca abundances in the models are sensitive to variations of rates of the reactions 37Ar(p,gamma)38K and 38K(p,gamma)39Ca, the nuclear physics uncertainties of these reactions cannot account for the discrepancy between the observed and predicted Ca abundances in novae. Furthermore, the overabundance of Ca has important implications for measuring 7Be in nova ejecta, as Ca lines are used to estimate 7Be abundances. If the Ca abundance is incorrectly determined, it could lead to inaccurate 7Be abundance estimates. Possible alternative explanations for the observed Ca overabundance are discussed.
format Preprint
id arxiv_https___arxiv_org_abs_2511_04874
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Calcium Excess in Novae: Beyond Nuclear Physics Uncertainties
Loria, Mallory
Denissenkov, Pavel
Ruiz, Chris
Herwig, Falk
Solar and Stellar Astrophysics
We examine Ca abundances in classical novae from spectroscopic observations spanning 65 years and investigate whether they are systematically high compared to those predicted by nova models. For the first time, we perform Monte Carlo simulations assessing the impact of nuclear reaction rate uncertainties on abundances predicted by multi-zone nova models. While the Ca abundances in the models are sensitive to variations of rates of the reactions 37Ar(p,gamma)38K and 38K(p,gamma)39Ca, the nuclear physics uncertainties of these reactions cannot account for the discrepancy between the observed and predicted Ca abundances in novae. Furthermore, the overabundance of Ca has important implications for measuring 7Be in nova ejecta, as Ca lines are used to estimate 7Be abundances. If the Ca abundance is incorrectly determined, it could lead to inaccurate 7Be abundance estimates. Possible alternative explanations for the observed Ca overabundance are discussed.
title Calcium Excess in Novae: Beyond Nuclear Physics Uncertainties
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2511.04874