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Time evolution of chemistry with fixed physical parameters in TMC-1

Part of: IAU Issue 315 - From Interstellar Clouds...

Published online by Cambridge University Press:  12 September 2016

Peter Berczik ,
Peter Bertsyk ,
Orsolya Fehér ,
Jorma Harju ,
Toshikazu Onishi  and
L. Viktor Tóth
Peter Berczik
Affiliation:
National Astronomical Observatories of China, Chinese Academy of Sciences, Beijing, China National Academy of Sciences of Ukraine, Main Astronomical Observatory, Kyiv, Ukraine.
Peter Bertsyk
Affiliation:
Department of Astronomy, Lorand Eotvos University, Budapest, Hungary. Department of Physical Chemistry, Lorand Eotvos University, Budapest, Hungary email: [email protected]
Orsolya Fehér
Affiliation:
Department of Astronomy, Lorand Eotvos University, Budapest, Hungary.
Jorma Harju
Affiliation:
Department of Physics, University of Helsinki.
Toshikazu Onishi
Affiliation:
Dept. of Physical Science, Osaka Prefecture University, Osaka, Japan.
L. Viktor Tóth
Affiliation:
Department of Astronomy, Lorand Eotvos University, Budapest, Hungary.
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Abstract

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We present a set of time dependent chemical evolution models (based on the UMIST† astrochemistry 2012 code, Woodall et al. (2007); McElroy et al. (2013) for a range of initial physical cloud parameters: 10 K < T < 20 K; 103 cm−3 < n(H2) < 5 · 104 cm−3; 1 < AV < 10 and with estimated values of scaled interstellar ultraviolet radiation field. Our computation model included the full UMIST gas-phase reaction network for 467 species Garrod et al. (2008), Graedel et al. (1982). We compare our chemical model results with the relative abundances of: CO, CH, OH, HCO+, HCN, HNC, NH3, N2H+ and H2CO molecules. We find significant time dependent variations of the chemical ratios of: X(NH3/H2); X(HCO+/H2) and X(HCO+/NH3). We derive an ammonia age spread for the parts of TMC-1 (Taurus Molecular Cloud-1) that looks more complex than previous estimated showed. Age estimates based on X(NH3/H2); X(HCO+/H2) and X(HCO+/NH3) were compared in 3 selected positions, and were found to be very similar (with ±9% differences).

Keywords

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Type
Poster Papers
Information
Proceedings of the International Astronomical Union , Volume 11 , Symposium S315: From Interstellar Clouds to Star-Forming Galaxies: Universal Processes? , August 2015 , E9
Copyright
Copyright © International Astronomical Union 2015 

References

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