Orion Molecular Ridge

The Orion molecular ridge has been mapped in 33 rotational transitions of 21 different chemical and isotopic species with the QUARRY receiver at FCRAO. Each map contains 360 pixels on a 0.41´ grid and covers an area 4.5´ × 12´ centered on Orion KL.

Shown below are a few of the molecular line maps which were obtained.

Many of the maps show very different morphologies. For example, the strongest emission from
CS occurs near Orion KL, while other molecules like NH peak north of Orion KL. The goal of the chemistry project is to understand how various processes (eg. density, temperature, star formation, etc...) alter the chemical conditions in the molecular gas.

A similar survey has been conducted in M17 and Cep A. Since Orion, M17, and Cep A are all sites of massive star formation, the chemistry survey will soon be extended to TMC1 and L134N in order to compare the chemical properties of the molecular gas in low mass star forming regions with those found in the regions where high mass stars are formed.

Contact Ted Bergin (eab@fcrao1.phast.umass.edu) for details.

Reference

Ungerechts, H. et al. 1994, Proceedings of the Zermatt Symposium on Molecular Clouds