Non-detection Of HC(S)SH: Estimating Upper Limits And Constraining Chemistry
The search for dithioformic acid (t-HC(S)SH) in star-forming regions is crucial for understanding interstellar sulfur chemistry and addressing the ‘missing sulfur’ problem.
Motivated by a recent claim of t-HC(S)SH detection in NGC 1333 IRAS 4A2, we independently reanalyzed the same ALMA dataset using comprehensive spectral and chemical modeling.
We find no credible evidence for t-HC(S)SH: all reported transitions are fully accounted for by known, abundant molecules, with no unblended features unique to t-HC(S)SH. We critically reassess the reported detection, deriving stringent upper limits on the column density (N_t-HC(S)SH <= 4 x 10^14 cm^-2) and the fractional abundance (<= 1 x 10^-10 relative to H2).
Our astrochemical models place these limits in context, showing the claimed detection likely results from spectral blending and inconsistent modeling assumptions. The non-detection aligns with chemical expectations given the rarity of complex and doubly sulfur-substituted molecules in hot corino environments.
Furthermore, our analysis establishes a rigorous framework to guide future searches for sulfur-bearing species and highlights the critical importance of thorough line identification and modeling practices in astrochemistry.
Dipen Sahu, Ankan Das, Prasanta Gorai, Victor M. Rivilla, Sheng-Yuan Liu, Bhalamurugan Sivaraman, Paola Caselli
Comments: Accepted for publication in the Astrophysical Journal
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2606.00569 [astro-ph.GA] (or arXiv:2606.00569v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2606.00569
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Submission history
From: Dipen Sahu
[v1] Sat, 30 May 2026 06:44:02 UTC (489 KB)
https://arxiv.org/abs/2606.00569
Astrobiology, Astrochemistry,
