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oai:www.ideals.illinois.edu:2142/20374 2023-07-10 col_2142_5131 col_2142_14807 com_2142_5130 com_2142_14806 com_2142_8903

http://hdl.handle.net/2142/20374 eng Copyright 1989 Loushin, Robert Stephen Physics, Astronomy and Astrophysics Webbink, Ronald F. Loushin, Robert Stephen 2011-05-07T12:37:23Z 2011-05-07T12:37:23Z 10000-01-01 1989 The biconical H II region S106 is a site of recent star formation; it consists of two ionized lobes flowing out from a central disk of cold molecular gas in which is embedded the newly formed massive star IRS 4. This entire complex is still embedded in the molecular cloud from which it formed. "I have found that the central disk is expanding at 2 km s$\sp{-1}$ and that clumps of molecular material are being ablated from its surface by the ionized outflow and accelerated to higher velocities. The ring is not rotating and may be supported by magnetic field pressure or the pressure of the ionized outflow. The origin and initial collimation of the ionized outflow remains unclear but must be occurring relatively near IRS 4. I argue that for distances from IRS 4 larger than 5"", the kinematics of the outflow is dominated by the pressure of the magnetic field. The magnetic field at the interface between the molecular gas and ionized outflow is very large, on the order of 1 mG. Finally, I show that there is a clear chemical evolution through the shock front between the ionized and molecular gas, with the HCO$\sp+$/CS ratio being greatly enhanced at the interface. Theoretical models are still much too crude to adequately explore the chemistry which occurs in a magnetic shock. Finally, I found that at long wavelengths, the spectral index of the continuum radiation becomes quite large, suggesting that at these wavelengths the emission is dominated by synchrotron radiation. Such emission requires both magnetic fields and relativistic electrons, which might be supplied in S106 by the first order Fermi effect in the shock region." Made available in DSpace on 2011-05-07T12:37:23Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9010941.pdf: 5239369 bytes, checksum: 7b2a8dc9d20c8e145076aedbc6d9007d (MD5) Previous issue date: 1989 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:43:28Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:19:01-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only AAI9010941 (UMI)AAI9010941 Molecular gas in S106: Morphology, kinematics, and chemistry of a star-forming region text Astronomy Astronomy University of Illinois at Urbana-Champaign Dissertation Ph.D.