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A. Meredith Hughes




Planetary systems form in circumstellar disks of gas and dust surrounding young stars. One open question in the study of planet formation involves understanding how different environments affect the properties of the disks and planets they generate. Understanding the properties of disks in high-mass star forming regions (SFRs) is critical since most stars—probably including our Sun—form in those regions. By comparing the disks in high-mass SFRs to those in better-studied low-mass SFRs we can learn about the role environment plays in planet formation. Here we present line-emission observations of the young binary system d253-1536 in the Orion Nebula from the Atacama Large Millimeter/submillimeter Array (ALMA) tracing CO(3-2), HCN(4-3), HCO+(4-3) and CS(7-6). We model each disk’s mass, radius, temperature structure, and molecular abundances by creating synthetic images using an LTE ray-tracing code and comparing simulated observations with the ALMA data in the visibility domain. We then compare our results to a previous study of molecular line emission from a single Orion proplyd, modeled using similar methods, and to previously characterized disks in low-mass SFRs to investigate the role of environment in disk chemistry and planetary system formation. We find atypical ratios of abundances, both between molecules in each disk as well as between the same molecule in different disks, as well as evidence that the two disks are interacting.



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