2025ApJ...990..186K

Line-resolved X-ray spectra of outflows from X-ray binaries are interesting since they provide quantifiable measures of the accreted material onto the compact object (black hole or neutron star), which can not be observed directly in the accretion disk. One such measurement that has been largely overlooked is that of the elemental abundances, which potentially provide insights into the origin of the ejected material. Using the Chandra/HETG grating spectrometer we measure and present elemental abundances in four low-mass X-ray binaries. We compare two measurement methods. One is by fitting line series of individual ions and reconstructing the absorption measure distribution (AMD), and the other is a global fit with one or two individual ionization components. All outflows feature a steep AMD strongly favoring high ionization degrees. The present abundances are consistent with previous works suggesting the abundances in the outflows are nonsolar. We find a tentative trend of increasing abundances with atomic number, which fits some core-collapse supernova models, but there is no exact match to a specific one.