| Name: Anshika Pandey |
| Affiliation: Banaras Hindu University |
| Conference ID: ASI2026_342 |
| Title: Chemical Modeling of ring molecules in Dark Clouds |
| Abstract Type: Poster |
| Abstract Category: Stars, Interstellar Medium, and Astrochemistry in Milky Way |
| Author(s) and Co-Author(s) with Affiliation: Anshika Pandey(Banaras Hindu University), Robin Garrod(University of Virginia), Amit Pathak(Banaras Hindu University), Alkendra Singh(Banaras Hindu University) |
| Abstract: The chemistry of dark interstellar clouds is strongly influenced by the balance between carbon and oxygen. Carbon-rich conditions favor the formation of aromatic molecules, while oxygen-rich environments open alternative pathways. Recent detections, such as benzonitrile (c-C ₆ H ₅ CN) in the Taurus Molecular Cloud 1 (TMC- 1), mark the first unambiguous evidence of an aromatic ring in space. Subsequent surveys suggest the presence of heteroaromatic species, including pyridine and phenol, which bridge simple hydrocarbons with prebiotic molecules. Their occurrence in dark, UV-shielded regions at temperatures below 10 K highlights the
survival and synthesis of fragile but complex organics through barrierless radical– hydrocarbon reactions. We carried out astrochemical modeling of TMC-1 using the three-phase gas–graincode MAGICKAL with an updated network, focusing on benzonitrile and related species under varying C/O ratios. Our results show that as the C/O ratio approaches unity, benzonitrile abundances rise by nearly an order of magnitude compared with predictions from the earlier GOTHAM network. The model reproduces the observed
fractional abundance of benzonitrile (~4 × 10 ⁻ ¹¹), while predicting pyridine at ~6 ×
10 ⁻ ¹². Phenol remains negligible in the gas (~10 ⁻ ² ⁰ ) but exhibits significant grain-
surface presence, suggesting a primarily solid-phase chemistry. We also extended the
network to include benzene and the phenyl radical, enabling comparison of aromatic
chemistry with and without heteroatoms. |
