Authors: Cabezas, C.; Pardo, J. R.; Agundez, M.; Tercero, B.; Marcelino, N.; Endo, Y.; de Vicente, P.; Guelin, M.; Cernicharo, J.


Publication date: 2023/04/21

DOI: 10.1051/0004-6361/202346462

Abstract: We report on the detection of a series of six lines in the ultra-deep Q-band integration towards IRC +10216 carried out with the Yebes 40 m telescope, which are in harmonic relation with integer quantum numbers J(u) from 12 to 18. After a detailed analysis of all possible carriers, guided by high-level quantum chemical calculations, we conclude that the lines belong to HMgCCCN, named hydridomagnesium cyanoacetylide. The rotational temperature and column density derived for HMgCCCN are 17.1 +/- 2.8 K and (3.0 +/- 0.6) x 10(12) cm(-2), respectively. The observed abundance ratio between MgCCCN and HMgCCCN is approximately three. In addition, we report the discovery in space, also towards IRC +10216, of sodium cyanoacetylide, NaCCCN, for which accurate laboratory data are available. For this species we derived a rotational temperature of 13.5 +/- 1.7 K and a column density of (1.2 +/- 0.2) x 10(11) cm(-2).