5 research outputs found
CoRoT photometry and high-resolution spectroscopy of the interacting eclipsing binary AU Mon
Analyses of very accurate CoRoT space photometry, past Johnson V
photoelectric photometry and high-resolution \'echelle spectra led to the
determination of improved and consistent fundamental stellar properties of both
components of AU Mon. We derived new, accurate ephemerides for both the orbital
motion (with a period of 11.113d) and the long-term, overall brightness
variation (with a period of 416.9d) of this strongly interacting Be + G
semi-detached binary. It is shown that this long-term variation must be due to
attenuation of the total light by some variable circumbinary material. We
derived the binary mass ratio = 0.17\p0.03 based on the
assumption that the G-type secondary fills its Roche lobe and rotates
synchronously. Using this value of the mass ratio as well as the radial
velocities of the G-star, we obtained a consistent light curve model and
improved estimates of the stellar masses, radii, luminosities and effective
temperatures. We demonstrate that the observed lines of the B-type primary may
not be of photospheric origin. We also discover rapid and periodic light
changes visible in the high-quality residual CoRoT light curves. AU Mon is put
into perspective by a comparison with known binaries exhibiting long-term
cyclic light changes.Comment: Accepted for publication in MNRA