Spectroscopic parameters for silacyclopropynylidene, SiC$_2$, from extensive astronomical observations toward CW Leo (IRC +10216) with the Herschel satellite

TL;DR

This study uses Herschel satellite observations to identify and refine spectroscopic parameters of SiC$_2$ in the star CW Leo, improving molecular frequency predictions through combined laboratory and astronomical data analysis.

Contribution

It provides updated spectroscopic parameters for SiC$_2$ by integrating laboratory and astronomical observations, addressing previous prediction inaccuracies.

Findings

Unambiguous detection of SiC$_2$ features in Herschel data.

Significant deviations in laboratory frequency predictions were corrected.

Enhanced molecular data accuracy for astrophysical modeling.

Abstract

A molecular line survey has been carried out toward the carbon-rich asymptotic giant branch star CW Leo employing the HIFI instrument on board of the Herschel satellite. Numerous features from 480 GHz to beyond 1100 GHz could be assigned unambiguously to the fairly floppy SiC$_2$ molecule. However, predictions from laboratory data exhibited large deviations from the observed frequencies even after some lower frequency data from this survey were incorporated into a fit. Therefore, we present a combined fit of all available laboratory data together with data from radio-astronomical observations.