On the Origin of Infrared Bands Attributed to Tryptophan in Spitzer Observations of IC 348
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Dhariwal_2024_ApJL_968_L9.pdf
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Published version
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Author(s) • • • • • • • • •
Dhariwal, Aditya
Speak, Thomas H
Zeng, Linshan
Rashidi, Amirhossein
Moore, Brendan
Berné, Olivier
Remijan, Anthony J
Schroetter, Ilane
McGuire, Brett A
Rivilla, Víctor M
Date Issued
June 1, 2024
Journal
The Astrophysical Journal Letters
Publisher
American Astronomical Society
Citation
Aditya Dhariwal et al 2024 ApJL 968 L9
Version
Final published version
Abstract
Abstract
Infrared emission features toward interstellar gas of the IC 348 star cluster in Perseus have been recently proposed to originate from the amino acid tryptophan. The assignment was based on laboratory infrared spectra of tryptophan pressed into pellets, a method which is known to cause large frequency shifts compared to the gas phase. We assess the validity of the assignment based on the original Spitzer data as well as new data from JWST. In addition, we report new spectra of tryptophan condensed in para-hydrogen matrices to compare with the observed spectra. The JWST MIRI data do not show evidence for tryptophan, despite deeper integration toward IC 348. In addition, we show that several of the lines attributed to tryptophan are likely due to instrumental artifacts. This, combined with the new laboratory data, allows us to conclude that there is no compelling evidence for the tryptophan assignment.
Infrared emission features toward interstellar gas of the IC 348 star cluster in Perseus have been recently proposed to originate from the amino acid tryptophan. The assignment was based on laboratory infrared spectra of tryptophan pressed into pellets, a method which is known to cause large frequency shifts compared to the gas phase. We assess the validity of the assignment based on the original Spitzer data as well as new data from JWST. In addition, we report new spectra of tryptophan condensed in para-hydrogen matrices to compare with the observed spectra. The JWST MIRI data do not show evidence for tryptophan, despite deeper integration toward IC 348. In addition, we show that several of the lines attributed to tryptophan are likely due to instrumental artifacts. This, combined with the new laboratory data, allows us to conclude that there is no compelling evidence for the tryptophan assignment.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
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DOI of Published Version
https://doi.org/10.3847/2041-8213/ad4d9a