The Chemical Clock of High-mass Star-forming Regions: N2H+/CCS

J. L. Chen, J. S. Zhang, J. X. Ge +6

Using the IRAM 30 m telescope, we presented observations of N2H+ J = 1-0, CCS JN = 87-76 and 77-66 lines toward a large sample of ultracompact HII regions (UC HIIs). Among our 88 U…