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		| Paper: | The Chemical Variation in the Orion A Cloud Cores |  
		| Volume: | 499, Revolution in Astronomy with ALMA: The Third Year |  
		| Page: | 191 |  
		| Authors: | Ohashi, S.; Tatematsu, K.; Choi, M.; Kang, M.; Umemoto, T.; Lee, J.-E.; Hirota, T.; Yamamoto, S.; Mizuno, N. |  
		| Abstract: | In order to investigate whether the column density ratios of carbon chain molecules (CCS, and HC3N) to N-bearing molecules (N2H+ and NH3) can be indicators of the chemical evolution in giant molecular clouds or not, we examined chemical characteristics of dense cores. As a results,  we found that the column density ratio, N(NH3)/N(CCS) and N(NH3)/N(HC3N), are high in star-forming cores and low in starless cores in the Orion A cloud. It may be suggested that the N(NH3)/N(CCS) and N(NH3)/N(HC3N) ratios are indicators of chemical evolution even in GMCs. We also found that the N(NH3)/N(CCS) ratio increases with the dissipation of turbulence. This means that the chemical evolution may be an indicator of the dynamical evolution of the core. |  
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