Ionize Hard: Interstellar PO+ Detection
We report the first detection of the phosphorus monoxide ion (PO+) in the interstellar medium. Our unbiased and very sensitive spectral survey toward the G+0.693–0.027 molecular cloud covers four different rotational transitions of this molecule, two of which (J = 1–0 and J = 2–1) appear free of con...
| Main Authors: | , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2022-04-01
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| Series: | Frontiers in Astronomy and Space Sciences |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fspas.2022.829288/full |
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| author | Víctor M. Rivilla Juan García De La Concepción Izaskun Jiménez-Serra Jesús Martín-Pintado Laura Colzi Belén Tercero Andrés Megías Álvaro López-Gallifa Antonio Martínez-Henares Sara Massalkhi Sergio Martín Sergio Martín Shaoshan Zeng Pablo De Vicente Fernando Rico-Villas Miguel A. Requena-Torres Miguel A. Requena-Torres Giuliana Cosentino |
| author_facet | Víctor M. Rivilla Juan García De La Concepción Izaskun Jiménez-Serra Jesús Martín-Pintado Laura Colzi Belén Tercero Andrés Megías Álvaro López-Gallifa Antonio Martínez-Henares Sara Massalkhi Sergio Martín Sergio Martín Shaoshan Zeng Pablo De Vicente Fernando Rico-Villas Miguel A. Requena-Torres Miguel A. Requena-Torres Giuliana Cosentino |
| author_sort | Víctor M. Rivilla |
| collection | DOAJ |
| description | We report the first detection of the phosphorus monoxide ion (PO+) in the interstellar medium. Our unbiased and very sensitive spectral survey toward the G+0.693–0.027 molecular cloud covers four different rotational transitions of this molecule, two of which (J = 1–0 and J = 2–1) appear free of contamination from other species. The fit performed, assuming local thermodynamic equilibrium conditions, yields a column density of N=(6.0 ± 0.7) × 1011 cm−2. The resulting molecular abundance with respect to molecular hydrogen is 4.5 × 10–12. The column density of PO+ normalized by the cosmic abundance of P is larger than those of NO+ and SO+, normalized by N and S, by factors of 3.6 and 2.3, respectively. The N(PO+)/N(PO) ratio is 0.12 ± 0.03, more than one order of magnitude higher than that of N(SO+)/N(SO) and N(NO+)/N(NO). These results indicate that P is more efficiently ionized than N and S in the ISM. We have performed new chemical models that confirm that the PO+ abundance is strongly enhanced in shocked regions with high values of cosmic-ray ionization rates (10–15 − 10–14 s−1), as occurring in the G+0.693–0.027 molecular cloud. The shocks sputter the interstellar icy grain mantles, releasing into the gas phase most of their P content, mainly in the form of PH3, which is converted into atomic P, and then ionized efficiently by cosmic rays, forming P+. Further reactions with O2 and OH produces PO+. The cosmic-ray ionization of PO might also contribute significantly, which would explain the high N(PO+)/N(PO) ratio observed. The relatively high gas-phase abundance of PO+ with respect to other P-bearing species stresses the relevance of this species in the interstellar chemistry of P. |
| first_indexed | 2024-04-12T11:41:30Z |
| format | Article |
| id | doaj.art-10240de3bfc24e458e07931a3cbe45d1 |
| institution | Directory Open Access Journal |
| issn | 2296-987X |
| language | English |
| last_indexed | 2024-04-12T11:41:30Z |
| publishDate | 2022-04-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Astronomy and Space Sciences |
| spelling | doaj.art-10240de3bfc24e458e07931a3cbe45d12022-12-22T03:34:37ZengFrontiers Media S.A.Frontiers in Astronomy and Space Sciences2296-987X2022-04-01910.3389/fspas.2022.829288829288Ionize Hard: Interstellar PO+ DetectionVíctor M. Rivilla0Juan García De La Concepción1Izaskun Jiménez-Serra2Jesús Martín-Pintado3Laura Colzi4Belén Tercero5Andrés Megías6Álvaro López-Gallifa7Antonio Martínez-Henares8Sara Massalkhi9Sergio Martín10Sergio Martín11Shaoshan Zeng12Pablo De Vicente13Fernando Rico-Villas14Miguel A. Requena-Torres15Miguel A. Requena-Torres16Giuliana Cosentino17Centro de Astrobiología (CSIC-INTA), Madrid, SpainCentro de Astrobiología (CSIC-INTA), Madrid, SpainCentro de Astrobiología (CSIC-INTA), Madrid, SpainCentro de Astrobiología (CSIC-INTA), Madrid, SpainCentro de Astrobiología (CSIC-INTA), Madrid, SpainObservatorio Astronómico Nacional (OAN-IGN), Madrid, SpainCentro de Astrobiología (CSIC-INTA), Madrid, SpainCentro de Astrobiología (CSIC-INTA), Madrid, SpainCentro de Astrobiología (CSIC-INTA), Madrid, SpainCentro de Astrobiología (CSIC-INTA), Madrid, SpainEuropean Southern Observatory, ALMA Department of Science, Santiago, ChileJoint ALMA Observatory, Department of Science Operations, Santiago, ChileStar and Planet Formation Laboratory, Cluster for Pioneering Research, RIKEN, Saitama, JapanObservatorio Astronómico Nacional (OAN-IGN), Madrid, SpainCentro de Astrobiología (CSIC-INTA), Madrid, SpainDepartment of Astronomy, University of Maryland, College Park, MD, United StatesDepartment of Physics, Astronomy and Geosciences, Towson University, Towson, MD, United StatesSpace, Earth and Environment Department, Chalmers University of Technology, Gothenburg, SwedenWe report the first detection of the phosphorus monoxide ion (PO+) in the interstellar medium. Our unbiased and very sensitive spectral survey toward the G+0.693–0.027 molecular cloud covers four different rotational transitions of this molecule, two of which (J = 1–0 and J = 2–1) appear free of contamination from other species. The fit performed, assuming local thermodynamic equilibrium conditions, yields a column density of N=(6.0 ± 0.7) × 1011 cm−2. The resulting molecular abundance with respect to molecular hydrogen is 4.5 × 10–12. The column density of PO+ normalized by the cosmic abundance of P is larger than those of NO+ and SO+, normalized by N and S, by factors of 3.6 and 2.3, respectively. The N(PO+)/N(PO) ratio is 0.12 ± 0.03, more than one order of magnitude higher than that of N(SO+)/N(SO) and N(NO+)/N(NO). These results indicate that P is more efficiently ionized than N and S in the ISM. We have performed new chemical models that confirm that the PO+ abundance is strongly enhanced in shocked regions with high values of cosmic-ray ionization rates (10–15 − 10–14 s−1), as occurring in the G+0.693–0.027 molecular cloud. The shocks sputter the interstellar icy grain mantles, releasing into the gas phase most of their P content, mainly in the form of PH3, which is converted into atomic P, and then ionized efficiently by cosmic rays, forming P+. Further reactions with O2 and OH produces PO+. The cosmic-ray ionization of PO might also contribute significantly, which would explain the high N(PO+)/N(PO) ratio observed. The relatively high gas-phase abundance of PO+ with respect to other P-bearing species stresses the relevance of this species in the interstellar chemistry of P.https://www.frontiersin.org/articles/10.3389/fspas.2022.829288/fullphosphorusinterstellar: abundancesinterstellar: cloudsastrochemistryinterstellar: ions |
| spellingShingle | Víctor M. Rivilla Juan García De La Concepción Izaskun Jiménez-Serra Jesús Martín-Pintado Laura Colzi Belén Tercero Andrés Megías Álvaro López-Gallifa Antonio Martínez-Henares Sara Massalkhi Sergio Martín Sergio Martín Shaoshan Zeng Pablo De Vicente Fernando Rico-Villas Miguel A. Requena-Torres Miguel A. Requena-Torres Giuliana Cosentino Ionize Hard: Interstellar PO+ Detection Frontiers in Astronomy and Space Sciences phosphorus interstellar: abundances interstellar: clouds astrochemistry interstellar: ions |
| title | Ionize Hard: Interstellar PO+ Detection |
| title_full | Ionize Hard: Interstellar PO+ Detection |
| title_fullStr | Ionize Hard: Interstellar PO+ Detection |
| title_full_unstemmed | Ionize Hard: Interstellar PO+ Detection |
| title_short | Ionize Hard: Interstellar PO+ Detection |
| title_sort | ionize hard interstellar po detection |
| topic | phosphorus interstellar: abundances interstellar: clouds astrochemistry interstellar: ions |
| url | https://www.frontiersin.org/articles/10.3389/fspas.2022.829288/full |
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