Where is the Driving Source for HH 168?
First Author:
Joel Green
Email: joel AT astro.as.utexas.edu
University of Texas at Austin
3001 Cedar St., Apt. #107
Austin, TX 78705
Coauthors:
Watson, Dan, University of Rochester
Neufeld, David, Johns Hopkins University
Bergin, Edwin, University of Michigan
Sonnentrucker, Paule, Johns Hopkins University
Forrest, William, University of Rochester
Sargent, Benjamin, STScI
Raines, Nicholas, University of Florida
Abstract
Herbig Haro objects are small emission nebulae that signify the interaction between both broad and collimated outflows from young stellar objects and the ambient molecular cloud material. GGD 37 is actually suspected to be an amalgamation of at least two superposed flows (including HH 168) traveling in different directions on the sky. Weaker shocks (less than ~10000 K) excite the molecular hydrogen into various rotational states detectable at IRS wavelengths, while strong shocks completely destroy the molecules and illuminate the ions. The Infrared Spectrograph on board Spitzer has enabled us to gather spatial information on a number of higher excitation species, and place greater constraints on the flows, allowing us to separate them chemically. How does the instability of driving sources of Herbig Haro jets affect their surrounding medium? By studying the pre-and post-shock gas, we can determine whether outflows from young stars have greater clumping or dispersive effects on their environment. Do outflows trigger or suppress star formation in the neighborhood? And finally, new observations from the IRS shed new light on the question: exactly where is the protostar that is driving HH 168?
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