Axion spectra and the associated x-ray spectra of low-mass stars

Axion particles are among the best candidates to explain dark matter and resolve strong $CP$ problem in Standard Model. If such a particle exists, core of stars will produce them large amounts. For first time, we predict axion spectra their associated luminosities for several low-mass stars---one two solar masses main sequence post-main stages evolution. Equally, also compute x-ray excess emission resulting from conversion axions back photons presence magnetic field envelope these stars. Hence, given star have unique spectrum ${L}_{a}$ luminosity. And if has its stellar envelope, it show characteristic ${L}_{a\ensuremath{\gamma}}$ Such radiation add up electromagnetic ${L}_{X}$ luminosity star. The present study focuses on models with an axion-photon coupling constant, $5\text{ }{10}^{\ensuremath{-}11}\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$, value just below most recent upper limit $6.6\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$ found by CAST IAXO helioscopes. range parameters discussed here spans many models' parameter space, including DFSZ KSVZ models. We that mass ${10}^{\ensuremath{-}7}$ ${10}^{\ensuremath{-}5}\text{ }\mathrm{eV}$ constant averaged energy varies 1 5 KeV, ranging ${10}^{\ensuremath{-}6}$ $7\text{ }{10}^{\ensuremath{-}3}{L}_{\ensuremath{\bigodot}}$. }{10}^{\ensuremath{-}8}$ ${10}^{\ensuremath{-}5}{L}_{\ensuremath{\bigodot}}$ $31{0}^{4}\text{ }\mathrm{G}$ atmospheres. Most predictions larger than observed some Therefore, preliminary results potential next generation missions constrain classes