Observations of CH3OH and CH3CHO in a Sample of Protostellar Outflow Sources

Authors: Holdship, Jonathan; Viti, Serena; Codella, Claudio; Rawlings, Jonathan ; Jimenez-Serra, Izaskun; Ayalew, Yenabeb ; Curtis, Justin ; Habib, Annur ; Lawrence, Jamel ; Warsame, Sumaya ; Horn, Sarah
Arxiv: https://arxiv.org/abs/1904.11360
DOI: https://doi.org/10.3847/1538-4357/ab1f8f

As part of the ORBYTS programme, a group of secondary school students in London studied the emission of COMs in protostellar outflows. They were provided with data from IRAM 30 m Observations toward eight protostellar outflow sources that were taken in the 96-176 GHz range. The students detected transitions of CH3OH and CH3CHO were detected in seven of them. The integrated emissions of the transitions of each species that fell into the observed frequency range were measured and fit using RADEX and LTE models. Column densities and gas properties inferred from this fitting are presented. The ratio of the A and E-type isomers of CH3OH indicates that the methanol observed in these outflows was formed on the grain surface. Both species demonstrate a reduction of terminal velocity in their line profiles in faster outflows, indicating destruction in the post-shock gas phase. This destruction, and a near constant ratio of the CH3OH and CH3CHO column densities, imply it is most likely that CH3CHO also forms on the grain surface.