The mid-infrared molecular inventory towards Orion IRc2 by Sarah Nickerson et al. on Wednesday 30 November

We present the first high spectral resolution mid-infrared survey in the

Orion BN/KL region, covering 7.2 to 28.3 micron. With SOFIA/EXES we target the

enigmatic source Orion IRc2. While this is in the most prolifically studied

massive star-forming region, longer wavelengths and molecular emission lines

dominated previous spectral surveys. The mid-infrared observations in this work

access different components and molecular species in unprecedented detail. We

unambiguously identify two new kinematic components, both chemically rich with

multiple molecular absorption lines. The "blue clump" has vLSR = -7.1 \pm 0.7

km/s and the "red clump" 1.4 \pm 0.5 km/s. While the blue and red clumps have

similar temperatures and line widths, molecular species in the blue clump have

higher column densities. They are both likely linked to pure rotational H2

emission also covered by this survey. This work provides evidence for the

scenario that the blue and red clumps are distinct components unrelated to the

classic components in the Orion BN/KL region. Comparison to spectroscopic

surveys towards other infrared targets in the region show that the blue clump

is clearly extended. We analyze, compare, and present in depth findings on the

physical conditions of C2H2, 13CCH2, CH4, CS, H2O, HCN, H13CN, HNC, NH3, and

SO2 absorption lines and an H2 emission line associated with the blue and red

clumps. We also provide limited analysis of H2O and SiO molecular emission

lines towards Orion IRc2 and the atomic forbidden transitions [FeII], [SI],

[SIII], and [NeII].

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.15707v1