The ultraviolet continuous and emission line spectra of the Herbig-Haro objects HH 2 and HH 1.

Abstract

Recent studies of the continuous spectrum of Herbig-Haro (HH) objects at optical and near-infrared wavelengths and the observation of continuous radiation in the ultraviolet have shown an unexpectedly steep increase of the flux toward shorter wavelengths. The present investigation provides the results of ultraviolet observations of HH 2. The obtained data are compared with the HH 1 data. It is found that HH 2 has an ultraviolet continuous and emission-line spectrum which is similar to that of HH 1. The UV line spectrum of HH 2H indicates an even somewhat larger ionization than does the HH 1 spectrum. As in HH1, the UV emission-line spectrum shows a much higher degree of ionization than that derived from the optical spectrum. Consequently, the same difficulty arises as in the case of HH 1. The complete UV plus optical spectrum cannot be explained by a single plane-parallel shock-wave model.