===== On the Detection of CaC<sub>2</sub> in Circumstellar Envelopes =====

Calciumcyclopropynylidene, CaC<sub>2</sub>, is a homolog of MgC<sub>2</sub> and somewhat related to silacyclopropynylidene, SiC<sub>2</sub>.\\
H. Gupta, P. B. Changala, J. Cernicharo, J. R. Pardo, M. Agúndez, C. Cabezas, B. Tercero, M. Guélin, and M. C. McCarthy\\
reported on the\\
**[[https://doi.org/10.3847/2041-8213/ad3336|Calcium Chemistry in Carbon-rich Circumstellar Environments: The Laboratory and Astronomical Discovery of Calcium Dicarbide, CaC<sub>2</sub>]]**\\
//Astrophys. J. Lett// **966**, Art. No. L28 (2024).\\
14 //a//-type lines with 0 ≤ //J// ≤ 8 and //K<sub>a</sub>// ≤ 4 between 14 and 115 GHz were identified for the main <sup>40</sup>Ca isotopolog employing the GBT 100 m, Yebes 40 m, and IRAM 30 m dishes. The observations with the GBT were dedicated ones, the other results were obtained in the couses of molecular line surveys of CW Leonis. These lines have good to reasonable signal-to-noise ratios, and several lines are unblended. Transitions of minor isotopologs were not identified. The derived column density ratio of MgC<sub>2</sub>/CaC<sub>2</sub> is roughly 2.\\
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Contributor(s): H. S. P. Müller; 05, 2024

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