The evolutionary history of ultra-compact accreting binaries. I. Chemical abundances and formation channel of the eclipsing AM CVn system ZTF J225237.05-051917.4 from HST spectroscopy

W. Yu, A. F. Pala, T. Kupfer +33

AM Canum Venaticorum (AM CVn) stars are ultra-compact binary systems composed of a white dwarf (WD) primary accreting from a H-deficient donor. They are important as potential prog…