A rich molecular chemistry in the gas of the IC 348 star cluster of the Perseus Molecular Cloud

Abstract

We present Spitzer 10-34 μm spectroscopic observations of the diffuse gas in the inner region of the star-forming region IC 348 of the Perseus Molecular Cloud. We find evidence for the strongest mid-IR bands of common molecules as H\textsubscript{2}, OH, H\textsubscript{2}O,CO\textsubscript{2} and NH\textsubscript{3} and of several carbonaceous molecules which may play an important role in the production of more complex hydrocarbons: HCN, C\textsubscript{2}H\textsubscript{2}, C\textsubscript{4}H\textsubscript{2}, HC\textsubscript{3}N, HC\textsubscript{5}N, C\textsubscript{2}H\textsubscript{6}, C\textsubscript{6}H\textsubscript{2}, C\textsubscript{6}H\textsubscript{6}. The excitation diagram of H\textsubscript{2} reveals the presence of warm gas (270 +- 30 K) at the observed locations. Assuming this temperature, the derived abundances of CO\textsubscript{2} and NH\textsubscript{3} relative to H\textsubscript{2} are 10\textsuperscript{-8} and 10\textsuperscript{-7}, respectively. From the water lines we obtain an abundance of order 10\textsuperscript{-6} and higher gas temperatures. The abundances derived for HCN and C\textsubscript{2}H\textsubscript{2}, key molecules in the development of prebiotic building blocks, are of order 10\textsuperscript{-7} and 10\textsuperscript{-9}, respectively. More complex molecules such as PAHs and the fullerenes C\textsubscript{60} and C\textsubscript{70} are also present. IC 348 appears to be very rich and diverse in molecular content. The JWST spectroscopic capabilities may provide details on the spatial distribution of all these molecules and extend the present search to more complex hydrocarbons.

33 pages, 24 figures, 4 tables, ACCEPTED in MNRAS

References in corpus (12)

• Complex Chemistry in Star-Forming Regions: An Expanded Gas-Grain Warm-up Chemical Model
• 2021 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules
• An Ammonia Spectral Atlas of Dense Cores in Perseus
• Water in star-forming regions (WISH): Physics and chemistry from clouds to disks as probed by Herschel spectroscopy
• The full infrared spectrum of molecular hydrogen
• CASSIS: The Cornell Atlas of Spitzer/Infrared Spectrograph Sources. II. High-resolution observations
• The PAH emission characteristics of the reflection nebula NGC2023
• Discovery of superthermal hydroxyl (OH) in the HH211 outflow
• Interstellar ice analogs: band strengths of H${}_2$O, CO${}_2$, CH${}_3$OH, and NH${}_3$ in the far-infrared region
• High-Resolution Mid-Infrared Spectroscopy of GV Tau N: Surface Accretion and Detection of Ammonia in a Young Protoplanetary Disk
• Efficiency of the top-down PAH-to-fullerene conversion in UV irradiated environments
• Molecular hydrogen emission in the interstellar medium of the Large Magellanic Cloud

Cited by in corpus (1)

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