000002188 001__ 2188
000002188 005__ 20160706143951.0
000002188 0247_ $$2DOI$$a10.1051/0004-6361/201219010
000002188 037__ $$aASTROimport-345
000002188 100__ $$aSemaan, T.
000002188 245__ $$aStudy of a sample of faint Be stars in the exofield of CoRoT. I. Spectroscopic characterization
000002188 260__ $$c2013
000002188 520__ $$aContext. Be stars are probably the most rapid rotators among stars in the main sequence (MS) and, as such, are excellent candidates to study the incidence of the rotation on the characteristics of their non-radial pulsations, as well as on their internal structure. Pulsations are also thought to be possible mechanisms that help the mass ejection needed to build up the circumstellar disks of Be stars.  Aims: The purpose of this paper is to identify a number of faint Be stars observed with the CoRoT satellite and to determine their fundamental parameters, which will enable us to study their pulsation properties as a function of the location in the HR diagram and to search for correlations with the light outbursts, which are possibly produced by discrete mass ejections.  Methods: We identified those objects in the exofields of CoRoT presenting the Be phenomenon using Ha surveys, as well as automated methods based on pulsation properties that we finally confirmed with FLAMES/GIRAFFE and X-shooter spectroscopic observations at VLT/ESO, and with near-IR photometry. The spectra were 1) corrected for the veiling effect, 2) treated with the GIRFIT code to determine apparent fundamental parameters, and 3) corrected with the FASTROT code for effects induced by the rapid rotation.  Results: A list of 41 Be star candidates were found from photometric and spectroscopic criteria. The spectral coverage useful for determining the fundamental parameters was obtained for only about half of them. We then spectroscopically identified 21 Be stars, two probable Be stars, and two B stars contaminated by the Sh 2-284 nebulosity. A short description of the spectral characteristics of each star is given. The fundamental parameters and, in particular, the rotation frequency νr (cycles per day) were all corrected for rotational effects at rotation rates ranging from Ω/Ωc = 0.8 to 1.0. We have determined the positions of Be stars in the HR diagram and find two of them located beyond the MS phase.  Conclusions: The well-determined fundamental parameters presented in this paper for a statistically reliable sample of Be stars will enable us in forthcoming papers to compare the properties of stars as pulsators either according to their location in different regions of the HR diagram or with those predicted from theory. Appendices are only available in electronic form at http://www.aanda.org
000002188 700__ $$aHubert, A. M.
000002188 700__ $$aZorec, J.
000002188 700__ $$aMartayan, C.
000002188 700__ $$aFrémat, Y.
000002188 700__ $$aGutiérrez-Soto, J.
000002188 700__ $$aFabregat, J.
000002188 773__ $$cA130$$pAstronomy and Astrophysics$$v551$$y2013
000002188 85642 $$ahttp://esoads.eso.org/abs/2013A%26A...551A.130S
000002188 905__ $$apublished in
000002188 980__ $$aREFERD