Phase Resolved Blue Spectroscopy of SS433

摘要

Despite more than 20 years of study, we still possess only limited constraints on the fundamental properties of SS433. With the exception of the 13d period, orbital parameters are ill-constrained, and hence the nature of both compact object, a neutron star or black hole, or the mass donor are still unknown. However, newly acquired high resolution blue spectra, taken when the precessing disc is closest to edge-on, provide the strongest evidence yet for a massive, A4 supergiant donor, in addition to expanding the phase constraints for further observations of the donor.