  Diffuse far-UV emission arising from the edge of the Orion-Eridanus
superbubble was observed with the SPEAR imaging spectrometer, revealing
numerous emission lines arising from both atomic species and H2. Spatial
variations in line intensities of CIV, SiII, and OVI, in comparison with soft
X-ray, H-alpha and dust data, indicate that these ions are associated with
processes at the interface between hot gas inside the bubble and the cooler
ambient medium. Thus our observations probe physical conditions of an evolved
thermal interface in the ISM.

Astrophysics