Abstract
This paper presents a compilation that includes a large fraction of the spectrophotometric observations of Herbig-Haro (HH) objects published (by a number of different authors) from 1981 through 1993. Our compilation includes 45 separate condensations of 31 different outflows, for all of which both blue and red spectra (in the range from ~ 3700 Å to ~ 8000-10000 Å) are available. From this data set, we have chosen a number of line ratios (namely, [O III] 5007/Hβ, [Ne III] 3868/Hβ, [O II] (3726+3729)/Hβ, [N II] 6583/Hβ, [O I] 6300/Hα, [N I] (5198+5200)/Hβ, [Ca II] 7291/Hα, [S II] (4068+4076)/Hβ and [S II] (6717+6731)/Hα) which are not strongly affected by reddening. We then study the different correlations that are found between these line ratios, and compare the results with predictions from shock wave models. We also use the compiled data set to derive a quantitative criterion (based on the [O III] 5007/Hβ and [S II] (6717+6731)/Hα line ratios) to divide HH spectra into the high, intermediate and low excitation categories. Finally, we obtain empirical determinations of ne (from the [S II] 6731/6717 ratio) for the HH condensations of our sample.
