Fig. 3a and b. Comparison of observed [3 ] 5007Å line profiles of other proplyds (gray histogram) with the models (heavy solid line). Model components as in Fig. 2b. The region of the spectrum that may be uncertain due to background subtraction is indicated by the light gray rectangle. a  LV 1 (OW 168-326E). b  LV 2 (OW 167-317). c  LV 3 (OW 163-317). d  OW 171-334 .