Astrochemistry

Chemical Complexity Of Phosphorous Bearing Species In Various Regions Of The Interstellar Medium

By Keith Cowing

astro-ph.GA

June 1, 2021

Filed under astrochemistry

Chemical Complexity Of Phosphorous Bearing Species In Various Regions Of The Interstellar Medium — Chemical evolution of the abundances of CO, CN, CS, and HNC for the diffuse cloud model (nH = 300 cm−3 and ζ = 1.7 × 10−16 s −1 ) with the Cloudy code. The colored horizontal bands correspond to the observed abundances (Chantzos et al. 2020) toward the cloud with vLS R = −17 km s−1 , including the inferred uncertainties. The vertical dashed line indicates the visual extinction parameter of best agreement between observation and model results.

Phosphorus related species are not known to be as omnipresent in space as hydrogen, carbon, nitrogen, oxygen, and sulfur-bearing species. Astronomers spotted very few P-bearing molecules in the interstellar medium and circumstellar envelopes.

Limited discovery of the P-bearing species imposes severe constraints in modeling the P-chemistry. In this paper, we carry out extensive chemical models to follow the fate of P-bearing species in diffuse clouds, photon-dominated or photodissociation regions (PDRs), and hot cores/corinos. We notice a curious correlation between the abundances of PO and PN and atomic nitrogen. Since N atoms are comparatively abundant in diffuse clouds and PDRs than in the hot core/corino region, PO/PN reflects < 1 in diffuse clouds, << 1 in PDRs, and > 1 in the late warm-up evolutionary phase of the hot core/corino regions. During the end of the post-warm-up phase, we obtain PO/PN > 1 for hot core and < 1 for its low mass analog. We employ a radiative transfer model to investigate the transitions of some of the P-bearing species in diffuse cloud and hot core regions and estimate the line profiles. Our study estimates the required integration time to observe these transitions with ground-based and space-based telescopes. We also carry out quantum chemical computation of the infrared features of PH3 along with various impurities. We notice that SO2 overlaps with the PH3 bending-scissoring modes around ~ (1000 – 1100) cm-1. We also find that the presence of CO2 can strongly influence the intensity of the stretching modes around ~ 2400 cm-1 of PH3 . Milan Sil, Satyam Srivastav, Bratati Bhat, Suman Kumar Mondal, Prasanta Gorai, Rana Ghosh, Takashi Shimonishi, Sandip K. Chakrabarti, Bhalamurugan Sivaraman, Amit Pathak, Naoki Nakatani, Kenji Furuya, Ankan Das Comments: 44 pages, 28 figures, Accepted for the publication in The Astronomical Journal
Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2105.14569 [astro-ph.GA] (or arXiv:2105.14569v1 [astro-ph.GA] for this version)
Submission history
From: Ankan Das
[v1] Sun, 30 May 2021 15:24:00 UTC (2,729 KB)
https://arxiv.org/abs/2105.14569

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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