MWC 656 has been reported as classical Be star with a black hole companion. Revisited spectral variability properties render this unlikely, with a hot subdwarf more probable.

The main objective of this work is to improve our understanding of young fast-rotating stars evolving from the Herbig Ae/Be class to the Vega-like one. We observed with the VEGA instrument on CHARA one object so-called 51 Oph that is probably in such an evolutionary phase, allowing us to measure a mean stellar radius for the first time for this star and to show that the Hα emission was produced in a Keplerian rotating disc. However, additional observations are needed to improve our (u,v) plan coverage in order to measure the flattening of this close-to-critically rotating star and to probe the inner region of its circumstellar gaseous disc. These studies will help to disentangle the gas and dust emission around this late young star and will finally improve our understanding of the planet formation conditions in the inner regions of protoplanetary discs.

During their post-main sequence evolution, massive stars pass through several short-lived phases, in which they experience enhanced mass loss in the form of clumped winds and mass ejection events of unclear origin. The discovery that stars populating the blue luminous part of the Hertzsprung-Russell diagram can pulsate suggests that stellar pulsations might influence or trigger enhanced mass loss and eruptions. We present recent results for two objects in different phases: a B[e] star at the end of the main sequence and a B-type supergiant.

We present blue optical spectra of 92 members of h and χ Per obtained with the WIYN telescope at Kitt Peak National Observatory. From these spectra, several stellar parameters were measured for the B-type stars, including v sin i, Teff, log gpolar, M∗, and R∗. Strömgren photometry was used to measure Teff and log gpolar for the Be stars. We also analyze photometric data of cluster members and discuss the near- to mid-infrared excesses of Be stars.