Astron. Astrophys. 324, 177-184 (1997)

5. Conclusions

Despite the poor seeing conditions, the analysis of long-slit spectra of some selected Herbig Ae/Be stars show major differences compared to the lower-mass T Tauri stars. Within the uncertainties of the measurement (and the associated methodological errors) and considering the large distances to most of the objects, no extended forbidden [O I](1F) emission line region could be detected. Except in the case of Z CMa, no spectrum of the observed stars shows any sign of a high-velocity component (unlike in the case of the T Tauri stars).

In the case of AB Aur, the prototype Herbig Ae star in the northern hemisphere, the geometrical constraints on the size of the FELR of the [O I](1F) lines seem to rule out the existence of an important, optically thick, circumstellar accretion disk. This result tends therefore to confirm previous investigations on this star (Böhm & Catala 1993, BC).

Further models have to take into account the upper limits derived for the forbidden [O I](1F) emission line regions around these stars. A more precise determination of the distances of the observed objects would be of great help.

Spectro-imaging observations with adaptive optics would be the next step to bring light in the investigations of these interesting objects.

© European Southern Observatory (ESO) 1997

Online publication: May 26, 1998

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