Enhanced Hα activity at periastron in the young and massive spectroscopic binary HD 200775?

Context. Young close binaries clear central cavities in their surrounding circumbinary disk from which the stars can still accrete material. This process takes place within the very first astronomical units, and is still not well constrained as the observational evidence has been gathered, until now, only by means of spectroscopy. Aims. The young object HD 200775 (MWC 361) is a massive spectroscopic binary (separation of ∼15.9 mas, ∼5.0 AU), with uncertain classification (early/late Be), that shows a strong and variable Hα emission. We aim to study the mechanisms that produce the Hα line at the AU-scale. Methods. Combining the radial velocity measurements and astrometric data available in the literature, we determined new orbital parameters. With the VEGA instrument on the CHARA array, we spatially and spectrally resolved the Hα emission of HD 200775 on a scale of a few milliarcseconds, at low and medium spectral resolutions (R∼1600 and 5000) over a full orbital period (∼3.6 years)