Identifying the companions of chemically peculiar red giants

Although the peculiar surface abundances of Tcpoor S stars in six symbioticsbinaries suggest that the compact object should be a white dwarf, the Xrayspectrum from at least one member of this class points to the presence of aneutron star. For that object, the Xray spectrum can be modeled as dueComptonized blackbody emission with the seedphotons coming from the neutronstar. To determine if chemically peculiar symbiotics host a white dwarf or aneutron star, we propose to obtain XMMNewton Xray spectra of four suchsymbiotics. This proposal has implications for our understanding of the originof polluted atmospheres and of binary stellar evolution. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]