Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) V. Tracing cavity walls and shocked knots with nonthermally desorbed CH₃OH in BHR71-IRS1

@misc{yun2026complex,
  title = {{Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) V. Tracing cavity walls and shocked knots with nonthermally desorbed CH$_3$OH in BHR71-IRS1}},
  author = {H. -S. Yun and J. -E. Lee and J. K. Jørgensen and A. Coutens and A. L. Plunkett and M. N. Drozdovskaya and A. Belloche and J. -H. Jeong and P. Nazari and Y. -L. Yang and M. L. R. van 't Hoff and S. Maret and F. Cruz-Sáenz de Miera and D. Harsono and C. -H. Kim and Á. Kóspál and M. Lützen and S. Spezzano and S. Zeng},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.09500},
  eprint = {2610.09500},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.09500},
  note = {CC BY-NC-SA 4.0},
}

TY  - UNPB
TI  - Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) V. Tracing cavity walls and shocked knots with nonthermally desorbed CH_3OH in BHR71-IRS1
AU  - H. -S. Yun
AU  - J. -E. Lee
AU  - J. K. Jørgensen
AU  - A. Coutens
AU  - A. L. Plunkett
AU  - M. N. Drozdovskaya
AU  - A. Belloche
AU  - J. -H. Jeong
AU  - P. Nazari
AU  - Y. -L. Yang
AU  - M. L. R. van 't Hoff
AU  - S. Maret
AU  - F. Cruz-Sáenz de Miera
AU  - D. Harsono
AU  - C. -H. Kim
AU  - Á. Kóspál
AU  - M. Lützen
AU  - S. Spezzano
AU  - S. Zeng
PY  - 2026
DA  - 2026/10/07
PB  - arXiv
DO  - 10.48550/arxiv.2610.09500
UR  - https://arxiv.org/abs/2610.09500
AB  - Complex organic molecules are detected in both cold molecular clouds and the warm inner regions of protostars. Whether they are eventually inherited by protostars and planets or whether their chemistry is reset by in situ reactions remains unclear. Understanding the desorption mechanisms of these molecules is essential for tracing their chemical evolution. As part of the ALMA Large Program Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS), we investigate the CH_3OH emission that extends beyond the hot corino of BHR71-IRS1. We identified extended CH_3OH emission around BHR71-IRS1. We assessed characteristic emission structures by applying a principal component analysis. The physical properties of their line-emitting gas were derived under the local thermodynamic equilibrium (LTE) assumption through both rotational diagram and spectral modeling analyses. In total, 26 extended CH_3OH lines have been detected. These emission lines are distributed across (1) X-shaped cavity walls, (2) northern and southern shocked knots, and (3) eastern and southeastern components. The cavity walls exhibit excitation temperatures of ∼ 25~K and column densities of ∼ 10^14~cm^−2, while the knots show relatively higher excitation temperatures (70−120~K) and column densities (10^14−10^16~cm^−2). The physical properties of eastern and southeastern components are not well constrained under LTE conditions. Plausible desorption mechanisms are evaluated by comparing the physical parameters with model predictions. The low excitation temperatures and narrow line widths in the cavity walls favor a reactive desorption scenario driven by far-ultraviolet irradiation from IRS1. In contrast, the knots with higher excitation temperatures and column densities support the dust sputtering scenario induced by C-type shocks.
ER  -