A. Coutens, J.-C. Loison, A. Boulanger, E. Caux, H. S. P. Müller, V. Wakelam, S. Manigand, and J. K. Jørgensen
reported on
The ALMA-PILS survey: First Tentative Detection of 3-Hydroxypropenal (HOCHCHCHO) in the Interstellar Medium and Chemical Modeling of the C<sub>3</sub>H<sub>4</sub>O<sub>2</sub> Isomers
Astron. Astrophys. 660 (2022), Art. No. L6.
3-Hydroxypropenal is the enol form of malonaldehyde. This enolic form is more stable than the dial because of intermolecular hydogen bonding. The molecule was identified through 11 lines in Band 7 corresponding to 19 b-type rotational transitions. Some of these are fully or partially blended. Two additional lines were clearly detected in Band 6 data. Rotation-tunneling transitions of a-type symmetry may be observable for somewhat higher excitation temperatures. However, the rest frequencies of stronger ones with low values of Ka are so uncertain that they can not be identified unambiguously. Its fractional abundance with respect to methanol is ~10−4.
H. S. P. Müller, A. Coutens, J. K. Jørgensen, L. Margulès, R. A. Motiyenko, and J.-C. Guillemin
published on
The rotation-tunneling spectrum of 3-hydroxypropenal and confirmation of its detection toward IRAS 16293−2422 B
Astron. Astrophys. 687 (2024), Art. No. A8.
The authors reported a very extensive line list from new (sub-) millimeter spectroscopic measurements. They were able to constrain the rotational temperature to 125 K. No additional lines were identified in the PILS data, but 7 additional lines were identified in archival ALMA data of the same source and with a similar spatial resolution. The column density is roughly a factor of 2.2 lower than that of propanal, a factor of about 42 lower than that of propene, and about a factor of 3 higher than that of propenal. The detection is now certainly beyond any doubt.
Contributor(s): H. S. P. Müller; 04, 2022; 08, 2024