Poster Presentation
Doubly deuterated ethanol: Spectroscopy
Presenter: Judit Ferrer asensio (RIKEN, Star and Planet Formation Laboratory)
Complex organic molecules (COMs) have been ubiquiously detected in the Interstellar Medium (ISM). Not only COMs are a great tool for source characterisation, but these molecules constitute the organic budget that will be available for planets. Isotopic fractionation, and in particular deuterium fractionation, can be used to follow the origin and inheritance of molecular complexity throughout the star formation process (Caselli & Ceccarelli 2012; Ceccarelli et al. 2014, Nomura et al. 2022). Recent observations towards the protostellar core IRAS 16293-2422 have revealed high COMs deuteration levels, including doubly-deuterated COMs which present average doubly-to-singly deuterated ra- tios (D2/D) of 20%; methyl formate 22% (Manigand et al. 2019), dimethylether 15-20% (Richard et al. 2021), methanol 25% (Drozdovskaya et al. 2022) and acetaldehyde 20% (Ferrer Asensio et al. 2023). The high deuteration levels of these molecules have been suggested to link their formation on the pre-stellar core phase. Nevertheless, the D2/D ratio has just been observed for a small number of molecules, partly due to the lack of accurate spectroscopic catalogues.
In order to see if this trend is maintained for other COMs, we focus on doubly deuterated ethanol (CH3CD2OH). Ethanol is a molecule of astrophysical interest thought to be the precursor for other biologically-relevant COMs. The doubly-deuterated ethanol isotopologue has yet not been detected towards the ISM due to the lack of an accurate spectroscopic catalogue. In order to provide with the first detection of CH3CD2OH towards the ISM and derive its D2/D ratio, which will shead light on its origin and relation to other COMs, we study the rotational spectrum of CH3CD2OH in the 23 - 370 GHz frequency range. The measurements are carried with two different setups: the SUMIRE (Watanabe et al. 2021) in RIKEN for higher frequency and the Toyama Microwave Atlas in Toyama University for lower frequency. The analysis of the measured spectra will provide with an accurate spectroscopic catalogue which we will make available for the community. With this poster we want to highlight the key role of spectroscopic studies in the detection of new molecules in the new promising ALMA Band 1 observations.
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