Astrochemistry

ALMASOP. A Rotating Feature Rich in Complex Organic Molecules in a Protostellar Core

By Keith Cowing

Status Report

astro-ph.SR

June 21, 2025

Filed under astro-ph.SR, astrochemistry, exoplanet, Interstellar, interstellar complex organic molecules, Keplerian disk, protostar, protostellar core G192.12-11.10., Spectroscopy, young stellar objects

ALMASOP. A Rotating Feature Rich in Complex Organic Molecules in a Protostellar Core — The 1.3 mm continuum and the integrated intensity images for CO J = 2 − 1, C¹⁸O J = 2 − 1, and CH₃OH 5_{1,4 – 42,4} transitions. For each column, the label at the top shows the molecule species and the quantum number of the corresponding transition. In each panel, the dashed and dotted lines illustrate the axes across and along the outflow, respectively. Top: Integrated intensity images (rainbow rasters) overlaid with 1.3 mm continuum (black contours). The color scales of the raster maps are shown as fractions of the peaks, which are 2.53, 0.56, and 0.86 Jy beam⁻¹ km s⁻¹, respectively. The contour levels start from 20σ with a step of 20σ. Bottom: 1.3 mm continuum (green rasters) overlaid with integrated intensity images for blue- and red-shifted channels (blue and red contours, respectively). The color scales of the raster maps are shown as the fraction of the peak, which is 39 mJy beam⁻¹ . The integration ranges for the CO, C¹⁸O, and CH₃OH are 25.0, 4.05, and 7.50 km s⁻¹, respectively, with a center velocity at v_LSR = 10 km s⁻¹. The contour levels start from 10σ with a step of 10σ. The gold eclipse in each panel represent the beam size around 0.′′42. — astro-ph.SR

Interstellar complex organic molecules (COMs) in solar-like young stellar objects (YSOs), particularly within protostellar disks, are of significant interest due to their potential connection to prebiotic chemistry in emerging planetary systems.

We report the discovery of a rotating feature enriched in COMs, including CH₃OH, CH₃CHO, and NH₂CHO, in the protostellar core G192.12-11.10. By constructing a YSO model, we find that the COM-rich feature is likely located within or near the boundary of the Keplerian disk.

The image synthesis results suggest that additional heating mechanisms leading to a warm ring or a warm inner disk are required to reproduce the observed emission. We discuss possible origins of the COM-rich feature, particularly accretion shocks as a plausible cause for a warm ring.

Additionally, molecules such as C¹⁸O, H₂CO, DCS, H₂S, and OCS exhibit distinct behavior compared to CH₃OH, indicating a range of physical and chemical conditions within the region. The observed kinematics of H₂S and OCS suggest that OCS resides in regions closer to the central protostar than H₂S, consistent with previous experimental studies.

Shih-Ying Hsu, Chin-Fei Lee, Doug Johnstone, Sheng-Yuan Liu, Tie Liu, Leonardo Bronfman, Huei-Ru Vivien Chen, Somnath Dutta, David J. Eden, Naomi Hirano, Mika Juvela, Kee-Tae Kim, Yi-Jehng Kuan, Woojin Kwon, Chang Won Lee, Jeong-Eun Lee, Shanghuo Li, Sheng-Jun Lin, Chun-Fan Liu, Xunchuan Liu, J. A. López-Vázquez, Qiuyi Luo, Mark G. Rawlings, Dipen Sahu, Patricio Sanhueza, Hsien Shang, Kenichi Tatematsu, Yao-Lun Yang

Comments: 19 pages, 10+1 figures, accepted by ApJ
Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2506.15140 [astro-ph.GA] (or arXiv:2506.15140v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2506.15140
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Submission history
From: Shih-Ying Hsu
[v1] Wed, 18 Jun 2025 04:45:47 UTC (1,389 KB)
https://arxiv.org/abs/2506.15140
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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