A COMPILATION OF OPTICAL SPECTROPHOTOMETRY OF HH OBJECTS AND ITS TENTATIVE INTERPRETATION

This paper presents a compilation that includes a large fraction of th e spectrophotometric observations of Herbig-Haro (HH) objects publishe d (by a number of different authors) from 1981 through 1993. Our compi lation includes 45 separate condensations of 31 different outflows, fo r all of which both blue and red spectra (in the range from similar to 3700 Angstrom to similar to 8000-10000 Angstrom) are available. From this data set, we have chosen a number of line ratios (namely, [O III] 5007/H beta, [Ne III] 3868/H beta, [O II] (3726+3729)/H beta, [N II] 6583/H beta, [O I] 6300/H alpha, [N I] (5198+5200)/H beta, [Ca II] 729 1/H alpha, [S II] (4068+4076)/H beta and [S II] (6717+6731)/H alpha) w hich are not strongly affected by reddening. We then study the differe nt correlations that are found between these line ratios, and compare the results with predictions from shock wave models. We also use the c ompiled data set to derive a quantitative criterion (based on the [O I II] 5007/H beta and [S II] (6717+6731)/H alpha line ratios) to divide HH spectra into the high, intermediate and low excitation categories. Finally, we obtain empirical determinations of n(e), (from the [S II] 6731/6717 ratio) for the HH condensations of our sample.