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Organic Complexity in Protostellar Disk Candidates

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journal contribution
posted on 22.07.2019 by Jennifer B. Bergner, Rafael Martín-Doménech, Karin I. Öberg, Jes K. Jørgensen, Elizabeth Artur de la Villarmois, Christian Brinch
We present ALMA observations of organic molecules toward five low-mass Class 0/I protostellar disk candidates in the Serpens cluster. Three sources (Ser-emb 1, Ser-emb 8, and Ser-emb 17) present emission of CH3OH as well as CH3OCH3, CH3OCHO, and CH2CO, while NH2CHO is detected in just Ser-emb 8 and Ser-emb 17. Detecting hot corino-type chemistry in three of five sources represents a high occurrence rate given the relative sparsity of these sources in the literature, and this suggests a possible link between protostellar disk formation and hot corino formation. For sources with CH3OH detections, we derive column densities of 1017–1018 cm–2 and rotational temperatures of ∼200–250 K. The CH3OH-normalized column density ratios of large, oxygen-bearing COMs in the Serpens sources and other hot corinos span 2 orders of magnitude, demonstrating a high degree of chemical diversity at the hot corino stage. Resolved observations of a larger sample of objects are needed to understand the origins of chemical diversity in hot corinos, and the relationship between different protostellar structural elements on disk-forming scales.