# ALMA Images of the Orion Hot Core at 349 GHz

## TL;DR

This paper presents high-resolution ALMA images of the Orion Hot Core at 349 GHz, revealing complex filamentary structures, outflows, and a molecular ring, suggesting shock heating from outflows and explosions.

## Contribution

First high-resolution ALMA imaging of the Orion Hot Core at 349 GHz, unveiling detailed filamentary structures, outflows, and a molecular ring, advancing understanding of hot core dynamics.

## Key findings

- Filamentary structures trace SiO outflows from Source I.
- Detection of a molecular ring ~600 AU in diameter.
- Evidence of shock heating from outflows and explosions.

## Abstract

We present ALMA images of the dust and molecular line emission in the Orion Hot Core at 349 GHz. At 0.2" angular resolution the images reveal multiple clumps in an arc ~ 1" east of Orion Source I, the protostar at the center of the Kleinmann-Low Nebula, and another chain of peaks from IRc7 towards the southwest. The molecular line images show narrow filamentary structures at velocities > 10 km/s away from the heavily resolved ambient cloud velocity ~5 km/s. Many of these filaments trace the SiO outflow from Source I, and lie along the edges of the dust emission. Molecular line emission at excitation temperatures 300--2000 K, and velocities > 10 km/s from the ambient cloud, suggest that the Hot Core may be heated in shocks by the outflow from Source I or from the BN/Source I explosion. The spectral line observations also reveal a remarkable molecular ring, ~ 2" south of Source I, with a diameter ~ 600 AU. The ring is seen in high excitation transitions of HC3N, HCN v2=1, and SO2. An impact of ejecta from the BN/Source I explosion with a dense dust clump could result in the observed ring of shocked material.