Interfaces between Hot and Cool Gas: The Superbubble N51D

Large bubbles of hot gas created by massive stars and the subsequent supernovaeare a main ingredient for the understanding of structure and evolution of theinterstellar medium. Unfortunately, the detailed physics of such bubbles andthe interaction of hot gas with the cool ambient interstellar medium could onlybe studied theoretically and at low spectral or spatial resolution up to now.We propose to use XMM for a first detailed case study of these processes byobserving the superbubble N51D in the LMC. Combination of high quality Xrayspectra and images from XMM with our imaging and spectroscopy data from HST willallow a critical test for the theories of interstellar bubbles, conductionfronts, and mixing layers. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]