2021MNRAS.500..145E

We use spectra from 2011 and 2012 to investigate the distribution of local effective temperature and non-orbital velocity over the surface of the common envelope of this peculiar contact binary. There seems to be a hot surface flow from the more massive to the less massive (secondary) component, possibly equatorial, which extends roughly one quarter-way around both sides of that secondary star, corresponding to the hotspot postulated to explain the star's light-curve peculiarities. This feature is clear in the shape of the profiles of metallic lines, but it shows up in H α/H β profiles, as well. The profiles imply small flow velocities in contrast to those detected in some A-type W UMa systems, less than a few km s^–1 for the primary but indeterminate for the secondary. We also classify the star's spectrum (G1-2 V) and present more radial velocities confirming the Rucinski-Lu radial-velocity solution.