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Chemical Tracers of Pre-Brown Dwarf Cores Formed Through Turbulent Fragmentation

Published online by Cambridge University Press:  12 September 2016

Jonathan Holdship
Affiliation:
Department of Physics and Astronomy, University College London, WC1E 6BT, United Kingdom email: [email protected]
Serena Viti
Affiliation:
Department of Physics and Astronomy, University College London, WC1E 6BT, United Kingdom email: [email protected]
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Abstract

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A gas-grain time dependent chemical code, UCL_CHEM, has been used to investigate the possibility of using chemical tracers to differentiate between the possible formation mechanisms of brown dwarfs. We model the formation of a pre-brown dwarf core through turbulent fragmentation by following the depth-dependent chemistry in a molecular cloud through the step change in density associated with an isothermal shock and the subsequent freefall collapse once a bound core is produced. Trends in the fractional abundance of molecules commonly observed in star forming cores are then explored to find a diagnostic for identifying brown dwarf mass cores formed through turbulence. We find that the cores produced by our models would be bright in CO and NH3 but not in HCO+. This differentiates them from models using purely freefall collapse as such models produce cores that would have detectable transitions from all three molecules.

Type
Poster Papers
Copyright
Copyright © International Astronomical Union 2016 

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