Detection of C3O in the low-mass protostar Elias 18

TL;DR

This study combines laboratory experiments and astronomical observations to detect and understand the formation of carbon chain oxides like C3O in low-mass protostars, highlighting their solid-phase formation and subsequent gas-phase release.

Contribution

It provides experimental estimates of carbon chain oxide formation in icy grain mantles and reports the first detection of C3O in a low-mass protostar, linking laboratory data with astrophysical observations.

Findings

Detected C3O in Elias 18 at 38486.891 MHz.

Laboratory experiments estimate 2-3x10^-3 formation of carbon oxides in icy mantles.

Suggests solid-phase formation and desorption as key processes.

Abstract

We have performed new laboratory experiments which gave us the possibility to obtain an estimate of the amount of carbon chain oxides (namely C3O2, C2O, and C3O) formed after irradiation (with 200 keV protons) of pure CO ice, at 16 K. The analysis of laboratory data indicates that in dense molecular clouds, when high CO depletion occurs, an amount of carbon chain oxides as high as 2-3x10^-3 with respect to gas phase carbon monoxide can be formed after ion irradiation of icy grain mantles. Then we have searched for gas phase C2O and C3O towards ten low-mass young stellar objects. Among these we have detected the C3O line at 38486.891 MHz towards the low-mass protostar Elias 18. On the basis of the laboratory results we suggest that in dense molecular clouds gas phase carbon chain oxides are formed in the solid phase after cosmic ion irradiation of CO-rich icy mantles and released to the gas phase after desorption of icy mantles. We expect that the Atacama Large Millimeter Array (ALMA), thanks to its high sensitivity and resolution, will increase the number of carbon chain oxides detected in dense molecular clouds.