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Session 51 - Interstellar Medium II.
Display session, Thursday, January 08
The physical picture of the local interstellar medium (LISM) is one of an interconnected system of supershells carved out of the ambient gas by the energetics of stellar winds and supernovae. Six of these shell structures are expanding into a hot, pre-evacuated region within 400-600 pc called, perhaps misleadingly, the Local Bubble. A current theory is that the Local Bubble itself is the remnant of a largescale supershell structure, blown out by the stellar winds and supernovae of an OB association, beginning some 3 to 6 10^7 years ago. The OB associations comprising Gould's Belt and the gas and dust of Lindblad's Ring seem to define an expanding perimeter for this evacuated region. Furthermore, it is hypothesized that the current star formation in Gould's Belt was triggered by this expanding bubble/shell complex. To test this, we present a model which determines: a) the kinematics of an expanding shell structure in the ISM and b) the critical time for the onset of star formation in a shock compressed shell. For a given number of stellar wind and supernovae producing stars and ambient gas number density, the dimensions, velocity and age of a shell complex are calculated. These predictions are compared to known physical parameters for the Gould's Belt/ Lindblad's Ring structure.
Program listing for Thursday