Poster Presentation

Finding Snow Lines of CH₃OH and NH₃ in Orion KL - Insights from ALMA Band 1 Mapping

Author(s): Yo-Ling Chuang (ASIAA)

Presenter: Yoling Chuang (ASIAA)

Orion KL is a chemically rich high-mass star-forming region, characterized by strong molecular line emission and complex thermal structures. Using ALMA Band 1 data, we present rotational temperature (Trot) and column density (Ntot) maps of CH3OH and NH3, two key tracers of dense gas and warm chemistry. CH3OH, often considered a cornerstone molecule in the formation pathways of complex organic molecules (COMs), traces regions of active desorption and grain-surface chemistry, while NH3 serves as a robust gas thermometer. In the central Orion KL region encompassing the Hot Core, Source I, and surrounding gas, we find consistent Trot patterns between the two species, suggesting co-evolution or shared thermal excitation. The Ntot distributions further reveal abundance variations across the inferred snow lines (~100 K for CH3OH and ~90 K for NH3), offering new insights into the thermal-chemical structure and desorption processes shaping this prototypical high-mass star-forming environment.