Spectral classification of stars with the B[e] phenomenon

SMITH CASTELLI, A. V.; ZOREC, J.; CIDALE, L.

Córdoba

Conferencia; X Reunión Regional Latinoamericana de Astronomía; 2001

Unión Astronómica Internacional

Stars in different evolutionary stages and/or environments can show the B[e] phenomenon: forbidden emission lines in the visible spectral range and strong IR flux excess. A quick look at the list of known B[e] stars (Jaschek & Egret 1982, CDS-SP N* 4) reveals that the "B[e] phenomenon" concerns objects that may show properties of "classic" Be stars, supergiants, symbiotics, etc. Lamers et al. (1998, A&A, 340, 117) suggest to classify these objects into five classes according to different physical characteristics of the central stars and the circumstellar matter: sgB[e] (supergiants), HAeB[e] (pre-main sequence stars), cPNB[e] (compact planetary nebulae),  SymbioticB[e] and unclB[e] (unclassified B[e] stars). In order to establish possible relations between the stellar evolutionary stage and the presence of the B[e] phenomenon, reliable fundamental parameters of these objects must to be determined, which in most cases are still unknown. With this aim we obtained spectra of low resolution in the spectral region of the Balmer discontinuity of stars presenting the B[e] phenomenon. The spectra were obtained with the Boller & Chivens spectrograph at the Complejo Astronomico El Leoncito (CASLEO) in Argentina. We obtained a preliminary spectral classification of the observed stars in the BCD (Barbier-Chalonge-Divan) system (Cidale et al. 2001, A&A, 368, 160). From the measured parameters, which are model independent, we shall derive stellar fundamental quantities like T_eff, log g y M_bol, which will help to establish possible relations between the stellar evolutionary stage and the presence of the B[e] characteristics.