Stellar Evolution confronts Axion Models

TL;DR

This paper provides a comprehensive analysis of astrophysical data to refine constraints on axion properties, evaluate theoretical models, and assess the discovery potential of upcoming helioscopes like IAXO.

Contribution

It revisits stellar bounds on axion couplings, compares theoretical models with observational hints, and evaluates future detection prospects at helioscopes.

Findings

Refined bounds on axion-photon, nucleon, and electron couplings.

Identification of the most promising axion models fitting the data.

Assessment of IAXO's potential to discover or constrain axions.

Abstract

Axion production from astrophysical bodies is a topic in continuous development, because of theoretical progress in the estimate of stellar emission rates and, especially, because of improved stellar observations. We carry out a comprehensive analysis of the most informative astrophysics data, revisiting the bounds on axion couplings to photons, nucleons and electrons, and reassessing the significance of various hints of anomalous stellar energy losses. We confront the performance of various theoretical constructions in accounting for these hints, while complying with the observational limits on axion couplings. We identify the most favorable models, and the regions in the mass/couplings parameter space which are preferred by the global fit. Finally, we scrutinize the discovery potential for such models at upcoming helioscopes, namely IAXO and its scaled versions.