Pamela Freeman – The Carbon-based Molecules of High Mass Star Forming Regions AFGL 2591 and IRAS 20126

Quand :
28 février 2023 @ 11 h 00 min – 12 h 30 min
Où :
B18N, Salle Univers

Speaker : Pamela Freeman

Title: The Carbon-based Molecules of High Mass Star Forming Regions AFGL 2591 and IRAS 20126


There is a diverse chemical inventory in protostellar regions that has led to the classification of two extreme types of systems: hot corinos, for the hot and dense low-mass systems that contain complex organic molecules, and warm carbon chain chemistry sources, for the warm and dense regions near a protostar containing unsaturated carbon chain molecules. Since these definitions were presented by Ceccarelli et al. (2004) and Sakai et al. (2008), respectively, there has been a growing field to detect these sources and determine if these classes of molecules can co-exist. There have been few studies surveying these molecules in high mass star forming regions—places of significance as the birthplace of most stars. To address this, I have conducted spectral surveys in two high-mass star forming regions in Cygnus X—AFGL 2591 and IRAS 20126—with the Green Bank Telescope and the IRAM 30m Telescope. In these observations, I detect several lines of formaldehyde, H2CO, and methanol, CH3OH, as tracers of hot core chemistry, and several lines of propyne, CH3CCH, and cyclopropenylidene, c-C3H2, as tracers of carbon chain chemistry. With a local thermodynamic equilibrium model, I use the observed molecular spectra to determine the physical conditions of these regions, producing maps of the gas temperatures, column densities, and velocities. These results illuminate the possible physical and dynamical environments of complex organic and carbon chain molecules, and are an initial step in investigating the chemical evolution of carbon-based molecules in star forming regions. The chemical makeup of star forming clouds and protostellar systems leads directly into that of stellar and planetary systems; observing the chemical complexity of star formation and modeling its environment provides an invaluable link between these systems.