Astrochemistry

Survey of Complex Organic Molecules in Starless and Prestellar Cores in the Perseus Molecular Cloud

By Keith Cowing

Status Report

astro-ph.GA

August 22, 2024

Filed under astro-ph.GA, astrochemistry, astronomy, biochemistry, complex organic molecules, dust, gas, Interstellar, molecular cloud, organic chemistry, Perseus Molecular Cloud, prestellar core, protostellar disk, Spectroscopy, Taurus Molecular Cloud

Survey of Complex Organic Molecules in Starless and Prestellar Cores in the Perseus Molecular Cloud — Perseus Molecular Cloud H2 column density map from Herschel (Sadavoy et al. 2012; Pezzuto et al. 2012; Sadavoy et al. 2014). Overplotted are the numbered starless and prestellar cores observed (pink, gold and orange points) and those underlined in gold have had successful ARO 12m CH3CHO detections at the 𝜎𝑇mb = 6 mK level and were followed up with the Yebes 40m telescope. Cores 67 and 658 are italicized and labeled in blue, denoting these are the cores that were followed up with additional ARO 12m observations probing down to 𝜎𝑇mb = 2.5 mK. The remaining starless and prestellar cores are in magenta. In all cores CH3OH has been detected. For comparison, in green are the locations of the 27 protostars from the PEACHES sample with CH3OH detections (see their Table 5 in Yang et al. 2021). The apparent overlap in sources is a projection effect, as seen from the zoom-in insert panels for regions IC348 and NGC1333. The size of the starless and prestellar core circles are at a FWHM of 62 arcsec. — astro-ph.SR

Cold (∼10 K) and dense (∼105 cm−3) cores of gas and dust within molecular clouds, known as starless and dynamically evolved prestellar cores, are the birthplaces of low-mass (M ≤ few M⊙) stars. As detections of interstellar complex organic molecules, or COMs, in starless cores has increased, abundance comparisons suggest that some COMs might be seeded early in the star formation process and inherited to later stages (i.e., protostellar disks and eventually comets).

To date observations of COMs in starless cores have been limited, with most detections reported solely in the Taurus Molecular Cloud. It is therefore still a question whether different environments affect abundances. We have surveyed 35 starless and prestellar cores in the Perseus Molecular Cloud with the Arizona Radio Observatory (ARO) 12m telescope detecting both methanol, CH₃OH, and acetaldehyde, CH₃CHO, in 100% and 49% of the sample, respectively.

In the sub-sample of 15 cores where CH₃CHO was detected at >3σ (∼18 mK) with the ARO 12m, follow-up observations with the Yebes 40m telescope were carried out. Detections of formic acid, t-HCOOH, ketene, H₂CCO, methyl cyanide, CH₃CN, vinyl cyanide, CH₂CHCN, methyl formate, HCOOCH₃, and dimethyl ether, CH₃OCH₃, are seen in at least 20% of the cores.

We discuss detection statistics, calculate column densities, and compare abundances across various stages of low-mass star formation. Our findings have more than doubled COM detection statistics in cold cores and show COMs are prevalent in the gas before star and planet formation in the Perseus Molecular Cloud.

Samantha Scibelli, Yancy Shirley, Andrés Megías, Izaskun Jiménez-Serra

Comments: Accepted for publication in MNRAS. 25-page main text (w/ 18 figures) and 25-page appendix (w/ 7 figures) for a total of 50 pages
Subjects: Astrophysics of Galaxies (astro-ph.GA); Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2408.11613 [astro-ph.GA] (or arXiv:2408.11613v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2408.11613
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Submission history
From: Samantha Scibelli
[v1] Wed, 21 Aug 2024 13:41:30 UTC (3,292 KB)
https://arxiv.org/abs/2408.11613

Astrobiology, Astrochemistry,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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