English

Mapping physical parameters in Orion KL at high spatial resolution

Astrophysics of Galaxies 2022-01-12 v1

Abstract

The Orion Kleinmann-Low nebula (Orion KL) is notoriously complex and exhibits a range of physical and chemical components. We conducted high angular resolution (sub-arcsecond) observations of 13^13CH3_{3}OH ν=0\nu=0 (\sim0.3^{\prime\prime} and \sim0.7^{\prime\prime}) and CH3_3CN ν8=1\nu_8=1 (\sim0.2^{\prime\prime} and \sim0.9^{\prime\prime}) line emission with the Atacama Large Millimeter/submillimeter Array (ALMA) to investigate Orion KL's structure on small spatial scales (350{\le}350 au). Gas kinematics, excitation temperatures, and column densities were derived from the molecular emission via a pixel-by-pixel spectral line fitting of the image cubes, enabling us to examine the small-scale variation of these parameters. Sub-regions of the Hot Core have a higher excitation temperature in a 0.2^{\prime\prime} beam than a 0.9^{\prime\prime} beam, indicative of possible internal sources of heating. Furthermore, the velocity field includes a bipolar 78{\sim}7{-}8 km s1^{-1} feature with a southeast-northwest orientation against the surrounding 45{\sim}4{-}5 km s1^{-1} velocity field, which may be due to an outflow. We also find evidence of a possible source of internal heating toward the Northwest Clump, since the excitation temperature there is higher in a smaller beam versus a larger beam. Finally, the region southwest of the Hot Core (Hot Core-SW) presents itself as a particularly heterogeneous region bridging the Hot Core and Compact Ridge. Additional studies to identify the (hidden) sources of luminosity and heating within Orion KL are necessary to better understand the nebula and its chemistry.

Keywords

Cite

@article{arxiv.2110.13929,
  title  = {Mapping physical parameters in Orion KL at high spatial resolution},
  author = {Olivia H. Wilkins and P. Brandon Carroll and Geoffrey A. Blake},
  journal= {arXiv preprint arXiv:2110.13929},
  year   = {2022}
}

Comments

28 pages, 15 figures, to be published in ApJ

R2 v1 2026-06-24T07:12:38.671Z