Detection of Magnesium Polyacetylide Cations toward CW Leonis

J. Cernicharo, C. Cabezas, J. R. Pardo, M. Agúndez, O. Roncero, B. Tercero, N. Marcelino, M. Guélin, Y. Endo, and P. de Vicente
reported on the
The Magnesium Paradigm in IRC +10216: Discovery of MgC4H+, MgC3N+, MgC6H+, and MgC5N+
Astron. Astrophys. 672, Art. No. L13 (2023).
The molecules were identified in the course of a molecular line survey with the 40 m Yebes radio telescope between 31.0 and 50.3 GHz. All identifications relied on quantum chemical calculations in the absense of Laboratory spectroscopic data. Seven successive, unblended transitions with 11 ≤ J“ ≤ 17 were identified for MgC4H+. In addition, nine successive transitions with 25 ≤ J” ≤ 33 were identified between 72.4 and 95.6 GHz in data of an IRAM 30 m molecular line survey; two transitions were partly blended. 16 transitions with 26 ≤ J“ ≤ 41 were accessed in the case of MgC6H+. Four transitions were partly blended, one was blended heavily. Seven successive transitions with 11 ≤ J” ≤ 17 were identified for MgC3N+ of which five were partially blended. 16 transitions with 27 ≤ J“ ≤ 42 were accessed in the case of MgC5N+. Nine were partially blended, one heavily, and two lines were too week to be detected securely. The rotational temperatures are around 20 K; the value of ~10 K for MgC3N+ should probably be viewed with great caution. The abundance ratios are about 48 : 12 : 25 : 11 for MgC4H+, MgC3N+. MgC6H+, and MgC5N+, respectively. The cations are about a factor of 200 less abundant than their neutral counterparts in the case of MgC4H+ and MgC6H+, whereas is is about a factor of 100 for MgC3N+ and about a factor of 50 for MgC5N+. Again, the ratios for MgC3N+ should be viewed with caution.


Contributor(s): H. S. P. Müller; 05, 2023