Far-UV Observations of a Thermal Interface in the Orion-Eridanus Superbubble

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.