<i>γ</i>Cas stars: Normal Be stars with discs impacted by the wind of a helium-star companion?
<i>γ</i>Cas stars: Normal Be stars with discs impacted by the wind of a helium-star companion?
$\gamma$ Cas stars are a $\sim$1% minority among classical Be stars with hard but only moderately strong continuous thermal X-ray flux and mostly very early-B spectral type. The X-ray flux has been suggested to originate from matter accelerated via magnetic disk-star interaction, by a rapidly rotating neutron star (NS) companion …