Chemical Complexity of Phosphorous-bearing Species in Various Regions of the Interstellar Medium
Abstract
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 more 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 stage of the hot core/corino regions. During the end of the post-warm-up stage, 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.
- Publication:
-
The Astronomical Journal
- Pub Date:
- September 2021
- DOI:
- arXiv:
- arXiv:2105.14569
- Bibcode:
- 2021AJ....162..119S
- Keywords:
-
- Astrochemistry;
- Abundance ratios;
- Chemical abundances;
- Interstellar molecules;
- Molecular clouds;
- 75;
- 11;
- 224;
- 849;
- 1072;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 44 pages, 28 figures, Accepted for the publication in The Astronomical Journal