Cometary charge exchange diagnostics in UV and X‐ray

Bodewits, Dennis; Christian, D. J.; Carter, J. A.; Dennerl, K.; Ewing, Ian; Hoekstra, Ronnie; Lepri, S. T.; Lisse, C. M.; Wolk, S. J.

doi:10.1002/asna.201211659

Cited by 5 publications

(4 citation statements)

References 60 publications

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“…Therefore, these transitions provide significant contributions to EUV and X-ray radiation. CX emission from cometary comae has rich observational and theoretical backing, as reviewed by Bodewits et al (2012) and Dennerl et al (2012).…”

Section: A2mentioning

confidence: 99%

X-Rays Trace the Volatile Content of Interstellar Objects

Cabot,

Wang,

Seligman

2023

ApJ

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The nondetection of a coma surrounding 1I/‘Oumuamua, the first discovered interstellar object (ISO), has prompted a variety of hypotheses to explain its nongravitational acceleration. Given that forthcoming surveys are poised to identify analogs of this enigmatic object, it is prudent to devise alternative approaches to characterization. In this study, we posit X-ray spectroscopy as a surprisingly effective probe of volatile ISO compositions. Heavily ionized metals in the solar wind interact with outgassed neutrals and emit high-energy photons in a process known as charge exchange, and charge-exchange-induced X-rays from comets and planetary bodies have been observed extensively in our solar system. We develop a model to predict the X-ray flux of an ISO based on its chemical inventory and ephemeris. We find that while standard cometary constituents, such as H2O, CO2, CO, and dust, are best probed via optical or infrared observations, we predict strong X-ray emission generated by charge exchange with extended comae of H2 and N2—species that lack strong infrared fluorescence transitions. We find that XMM-Newton would have been sensitive to charge exchange emission from 1I/‘Oumuamua during the object’s close approach to Earth, and that constraints on composition may have been feasible. We argue for follow-up X-ray observations of newly discovered ISOs with close-in perihelia. Compositional constraints on the general ISO population could reconcile the apparently self-conflicting nature of 1I/‘Oumuamua and provide insight into the earliest stages of planet formation in extrasolar systems.

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Section: A2mentioning

confidence: 99%

X-Rays Trace the Volatile Content of Interstellar Objects

Cabot,

Wang,

Seligman

2023

ApJ

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“… 1996 ; Cravens 1997 ; Bodewits et al. 2012 ), but the Rosetta mission identified electron-neutral interactions in the analysis of UV spectra and optical images of 67P (Feldman et al. 2015 ; Bodewits et al.…”

Section: Plasmamentioning

confidence: 99%

The Plasma Environment of Comet 67P/Churyumov-Gerasimenko

et al. 2022

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The environment of a comet is a fascinating and unique laboratory to study plasma processes and the formation of structures such as shocks and discontinuities from electron scales to ion scales and above. The European Space Agency’s Rosetta mission collected data for more than two years, from the rendezvous with comet 67P/Churyumov-Gerasimenko in August 2014 until the final touch-down of the spacecraft end of September 2016. This escort phase spanned a large arc of the comet’s orbit around the Sun, including its perihelion and corresponding to heliocentric distances between 3.8 AU and 1.24 AU. The length of the active mission together with this span in heliocentric and cometocentric distances make the Rosetta data set unique and much richer than sets obtained with previous cometary probes. Here, we review the results from the Rosetta mission that pertain to the plasma environment. We detail all known sources and losses of the plasma and typical processes within it. The findings from in-situ plasma measurements are complemented by remote observations of emissions from the plasma. Overviews of the methods and instruments used in the study are given as well as a short review of the Rosetta mission. The long duration of the Rosetta mission provides the opportunity to better understand how the importance of these processes changes depending on parameters like the outgassing rate and the solar wind conditions. We discuss how the shape and existence of large scale structures depend on these parameters and how the plasma within different regions of the plasma environment can be characterised. We end with a non-exhaustive list of still open questions, as well as suggestions on how to answer them in the future.

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“…The solar wind CX mechanism has been used to model and interpret cometary X-ray and EUV emission spectra (Schwadron & Cravens 2000;Cravens 2002;Otranto et al 2006). An accurately quantified modeling is crucial to interpret the astronomical observations (Bodewits et al 2012;Machacek et al 2015), such as composition, velocity and flux of solar wind ions, and density and composition of neutral gases.…”

Section: Introductionmentioning

confidence: 99%

Benchmark n ℓ-resolved Cross Sections of Single and Double Charge Exchange Processes in 1.67–20 keV u⁻¹ C⁴⁺ Collisions with He

Guo

Zhang

Zhu

et al. 2022

ApJ

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State-resolved charge exchange (CX) cross sections are of the utmost importance for modeling related photon emissions existing in a broad range of astrophysical environments. With the cold-target recoil-ion momentum spectroscopy, we determined with high accuracy the state-resolved single and double CX cross sections at the quantum orbital angular momentum level for solar wind ion C4+ collisions with He in an energy range of 1.67–20 keV u−1, which allow one to benchmark the CX calculations in great detail, and to test the applicability of the analytical n- and ℓ-distribution models widely adopted by the astrophysical community. We found that the present measurements are well reproduced by the most recent state-of-the-art atomic–orbital close-coupling calculations. However, the CX models failed to give a consistent description on the measured ℓ distributions. The present work reveals that the velocity and collision partner species dependence effects as well as electronic correlations for multielectron processes should be included in an improved model. Alternatively, in future modeling to interpret high-resolution astrophysical observations the more elaborate quantum-mechanical calculations may be resorted to with confidence.

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Cometary charge exchange diagnostics in UV and X‐ray

Cited by 5 publications

References 60 publications

X-Rays Trace the Volatile Content of Interstellar Objects

X-Rays Trace the Volatile Content of Interstellar Objects

The Plasma Environment of Comet 67P/Churyumov-Gerasimenko

Benchmark n ℓ-resolved Cross Sections of Single and Double Charge Exchange Processes in 1.67–20 keV u⁻¹ C⁴⁺ Collisions with He

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Cometary charge exchange diagnostics in UV and X‐ray

Cited by 5 publications

References 60 publications

X-Rays Trace the Volatile Content of Interstellar Objects

X-Rays Trace the Volatile Content of Interstellar Objects

The Plasma Environment of Comet 67P/Churyumov-Gerasimenko

Benchmark n ℓ-resolved Cross Sections of Single and Double Charge Exchange Processes in 1.67–20 keV u−1 C4+ Collisions with He

Contact Info

Product

Resources

About

Benchmark n ℓ-resolved Cross Sections of Single and Double Charge Exchange Processes in 1.67–20 keV u⁻¹ C⁴⁺ Collisions with He