ISO-LWS grating spectroscopy: the case of R CrA star forming region

We present the far infrared spectra of the R CrA star forming region obtained with ISO-LWS. We collected a pointed observation on the Herbig Ae star R CrA and a raster scan covering the surrounding region, where HH100 (with its exciting source) and the pre-Main Sequence star T CrA are located. The [OI]63 mu m and the [CII]158 mu m lines have been detected in all the pointed positions, with a ratio consistent with PDR excitation. CO rotational lines (between J(up) = 14 and J(up) = 19) are detected on R CrA; from their intensities we derived, using a LVG model, the density and temperature of the emitting region. Other molecular transitions (OH and H2O) have been detected on the investigated objects; the derived cooling of all the molecular species is in agreement with C-shock as the likely excitation mechanism. The continuum emission of R CrA peaks around 100 mu m (as expected for a Herbig star) while the other sources (T CrA, HH100) show increasing continua up to similar to 200 mu m, indicating that they are probably less evolved sources.