Clump-scale chemistry in the NGC2264-D cluster-forming region

Abstract

We have conducted mapping observations toward the n3 and n5 positions in the NGC 2264-D cluster-forming region with the Atacama Compact Array (ACA) of the Atacama Large Millimeter/submillimeter Array (ALMA) in Band 3. Observations with 10000 au scale beam reveal the chemical composition at the clump scale. The spatial distributions of the observed low upper-state-energy lines of CH 3 OH are similar to those of CS and SO, and the HC 3 N emission seems to be predominantly associated with clumps containing young stellar objects. The turbulent gas induced by the star formation activities produces large-scale shock regions in NGC 2264-D, which are traced by the CH 3 OH, CS and SO emissions. We derive the HC 3 N, CH 3 CN, and CH 3 CHO abundances with respect to CH 3 OH. Compared to the n5 field, the n3 field is farther (in projected apparent distance) from the neighboring NGC 2264-C, yet the chemical composition in the n3 field tends to be similar to that of the protostellar candidate CMM3 in NGC 2264-C. The HC 3 N/CH 3 OH ratios in the n3 field are higher than those in the n5 field. We find an anti-correlation between the HC 3 N/CH 3 OH ratio and their excitation temperatures. The low HC 3 N/CH 3 OH abundance ratio at the n5 field implies that the n5 field is an environment with more active star formation compared with the n3 field.