HOPKINS ULTRAVIOLET TELESCOPE OBSERVATIONS OF H-2 EMISSION FROM HH-2

The Hopkins Ultraviolet Telescope spectrum of HH 2 shows Lyman band em ission below 1200 Angstrom, and it reveals H-2 bands in the quasi-cont inuum at longer wavelengths. The H-2 emission could arise either from Ly alpha fluorescence (as in other HH objects) or from collisional exc itation by hot electrons. The fluorescence hypothesis encounters some difficulty in explaining the lack of individual strong features, while the collisional hypothesis must explain the mixing of hot electrons i nto the molecular gas before photoionization or collisions with H atom s dissociate the molecules. The spectrum also provides a stringent upp er limit to the O VI flux. The upper limit appears to conflict badly w ith the predictions of bow-shock models that match the observed line w idths of HII 2A' and HH 2H.