1995A&A...295..504M

Spectral studies of the small emission knot (HH-object), located inside the cometary nebula GM1-27 (GN20.18.3), were performed with high spatial resolution. The radial velocities of the emission lines and maps of isointensities are given. Also the emission lines ratios and their spatial distribution are investigated. The velocity of the low excitation lines changes along the knot; for higher excitation lines this effect is absent. In addition, the lines of different excitation are shifted in position with regard to each other. The peak of the electron density in the head of the knot is prominent. It seems as if two zones of different excitation spatially separated for 10¹⁷cm, could exist inside the knot. A conclusion is drawn about the possibility of observational resolution of two excitation regions - bow-shock and Mach disk - in the knot. The star which drives the outflow appears to be of Herbig Ae type.