http://arxiv.org/abs/1807.00986
We report on ALMA band 4 observations of glycolaldehyde (CH${2}$OHCHO v=0, 1, 2) and ethylene glycol (aGg$^{\prime}$(CH${2}$OH)${2}$ and gGg$^{\prime}$(CH${2}$OH)${2}$) toward the solar-type protostar IRAS 16293-2422, which harbours a twin binary system (source A and B). Vibrationally excited glycolaldehyde is unambiguously identified in source B for the first time, constituting the first detection in interstellar space. Rotational transitions of gGg$^{\prime}$(CH${2}$OH)$_{2}$ are also firstly detected in source A. Multiple transitions spanning a wide energy range allow us to derive accurate physical parameters. Vibrationally excited glycolaldehyde transitions have a higher gas temperature and abundance than their rotational transitions. A larger number of spectral lines is found towards source B, which also has higher temperatures but lower abundances compared to source A. The results indicate different physical and chemical conditions for the two twin sources.
Y. Zhou, S. Qin, A. Sanchez-Monge, et. al.
Wed, 4 Jul 18
26/58
Comments: Submitted to ApJ