J. Cernicharo, C. Cabezas, J. R. Pardo, M. Agúndez, C. Bermúdez, L. Velilla-Prieto, F. Tercero, J. A. López-Pérez, J. D. Gallego, J. P. Fonfría, G. Quintana-Lacaci, M. Guélin, and Y. Endo
reported on the
Discovery of two new magnesium-bearing species in IRC+10216: MgC₃N and MgC₄H
Astron. Astrophys. 630, Art. No. L2 (2019).
The 40 m Centro Astronómico de Yebes dish and the IRAM 30 m dish were employed to observed 22 rotational transitions of magnesium monocyanoacetylide, MgC₃N, between N' = 12 and 40 and between 33 and 111 GHz toward the famous near-by carbon-rich AGB star CW Leonis. Many transitions show decent to good signal-to-noise ratios and are not or only slightly blended. Fine structure splitting is well-resolved at lower frequencies. The astronomical data were employed to derive spectroscopic parameters in the absence of laboratory data.

J. R. Pardo, C. Cabezas, J. P. Fonfría, M. Agúndez, B. Tercero, P. de Vicente, M. Guélin and J. Cernicharo reported on
Magnesium Radicals MgC₅N and MgC₆H in IRC +10216
Astron. Astrophys. 652, Art. No. L13 (2021).
The 40 m Centro Astronómico de Yebes dish was employed to observe 15 rotational transitions of magnesium cyanodiacetylide, MgC₅N, with N“ = 27 to 41 between 31.0 and 50.3 GHz toward the famous near-by carbon-rich AGB star CW Leonis. Some of the transitions displayed resolved fine structure (FS) splitting. 14 transitions appear to be unblended or only slightly blended. The identification of a new species is unambiguous. The identification of the carrier may be viewed with slight caution in the absence of laboratory data. However, the FS spltting is a very strong indicator that the identification is unambiguous as well. It is very interesting to note that MgC₅N has a column density only a factor of two lower than that of MgC₃N, but about a factor of six higher than that of MgCN. The authors justified this by their likely formation which involves radiative association reactions of Mg⁺ with HC_2n+1N. These ratios are similar to those of the isoelectronic MgC_2nH molecules. MgNC is about a factor of three more abundant than MgC₅N.

Contributor(s): H. S. P. Müller; 10, 2019; 09, 2021