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Session 25 - Stellar Winds, Accretion, & Molecular Clouds.
Oral session, Monday, January 15
La Condesa, Hilton

[25.03] The Fragmenting Stellar Wind Bubble at the Heart of OMC-1 Revealed

M. -M. Mac Low, M. J. McCaughrean (MPI for Astronomy)

The shocked molecular hydrogen observed at infrared wavelengths in the neighborhood of the BN-KL object in Orion has long been thought to be distributed in a thin layer. More recently, long fingers of shocked gas with clear bowshocks at the tips have been observed extending from the region of strongest emission. These fingers have been explained by Stone et al. (Nature, 1995, 377, 315) by invoking a stellar wind bubble fragmenting due to Rayleigh-Taylor instabilities caused by a sudden increase in its driving pressure, although such a bubble had not yet been observed. We used the MAGIC infrared camera/spectrometer on the Calar Alto 2.2m telescope to obtain a series of long-slit spectra covering the region, from which an accurately continuum-subtracted image in the 2.122-\mum line of shocked H_2 could be constructed. This image directly shows the fragmented stellar wind bubble invoked by Stone et al. We estimate the properties of the bubble based on this image and published observations of the velocity structure of the region.

Program listing for Monday