X-Ray Emissions from the Jovian System

Dunn, W. R.

doi:10.1007/978-981-16-4544-0_73-1

Cited by 6 publications

(9 citation statements)

References 130 publications

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“…Three out of the four cases show the majority of the concentrated, and most intense, X‐ray emissions are located in the X‐ray polar region, dominated by X‐ray noon. These emissions are therefore likely to be co‐located (and possibly linked) with the UV activity in the polar and swirl regions and possibly coincide with flaring UV emissions (e.g., Dunn, 2022; Elsner et al., 2005). Previous studies (e.g., Grodent, 2015; Grodent, Clarke, Waite et al., 2003; Greathouse et al., 2021) and references therein) have also identified the polar active region as the most dynamic of the UV polar emissions, producing flares and bright arc sub‐structures of a few hundred kilo‐Rayleigh (kR) lasting in the order of a few minutes.…”

Section: Resultsmentioning

confidence: 99%

Identifying the Variety of Jovian X‐Ray Auroral Structures: Tying the Morphology of X‐Ray Emissions to Associated Magnetospheric Dynamics

Weigt,

Jackman,

Moral Pombo

et al. 2023

JGR Space Physics

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We define the spatial clustering of X‐rays within Jupiter's northern auroral regions by classifying their distributions into “X‐ray auroral structures.” Using data from Chandra during Juno's main mission observations (24 May 2016 to 8 September 2019), we define five X‐ray structures based on their ionospheric location and calculate the distribution of auroral photons. The morphology and ionospheric location of these structures allow us to explore the possibility of numerous X‐ray auroral magnetospheric drivers. We compare these distributions to Hubble Space Telescope (HST) and Juno (Waves and MAG) data, and a 1D solar wind propagation model to infer the state of Jupiter's magnetosphere. Our results suggest that the five sub‐classes of “X‐ray structures” fall under two broad morphologies: fully polar and low latitude emissions. Visibility modeling of each structure suggests the non‐uniformity of the photon distributions across the Chandra intervals are likely associated with the switching on/off of magnetospheric drivers as opposed to geometrical effects. The combination of ultraviolet (UV) and X‐ray morphological structures is a powerful tool to elucidate the behavior of both electrons and ions and their link to solar wind/magnetospheric conditions in the absence of an upstream solar monitor. Although much work is still needed to progress the use of X‐ray morphology as a diagnostic tool, we set the foundations for future studies to continue this vital research.

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Section: Resultsmentioning

confidence: 99%

Identifying the Variety of Jovian X‐Ray Auroral Structures: Tying the Morphology of X‐Ray Emissions to Associated Magnetospheric Dynamics

Weigt,

Jackman,

Moral Pombo

et al. 2023

JGR Space Physics

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“…The magnetospheric compressional mode wave power and X‐ray emissions were found to pulse with a shared period of ∼25 min (Yao et al., 2021). The large‐scale compressional waves trigger EMIC (electromagnetic ion cyclotron) waves, which operate on smaller scales, as resonances between the magnetic field and the ion gyration (Dunn, 2022; Yao et al., 2021). The EMIC waves then further drive atmospheric precipitation of energetic sulfur and oxygen ions along the magnetic fields via a pitch angle diffusion process, thus generating the X‐ray auroral processes.…”

Section: Discussionmentioning

confidence: 99%

Long Exposure Chandra X‐Ray Observation of Jupiter's Auroral Emissions During Juno Plasmasheet Encounters in September 2021

McEntee,

Jackman,

Weigt

et al. 2023

JGR Space Physics

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On 15 September 2021, Chandra carried out a 40‐hr (∼4 jovian rotations) observation as part of its longest planetary campaign to study the drivers of jovian X‐ray aurora that may be linked to ultra‐low frequency (ULF) wave activity. During this time, Juno's orbit had taken the spacecraft into Jupiter's dusk magnetosphere. Here is believed to be the most probable location of ULF waves propagating along jovian magnetic field lines that drive the X‐ray auroral emissions. This is the first time that this region has been observed by an orbiter since Galileo >20 years ago, and never before has there been contemporaneous in situ and X‐ray observations. A 1D solar wind propagation model identifies a compression event near the midpoint of the 40‐hr observation window. The influence of a compression is confirmed when comparing the measured magnetic field in the dusk lobes of the magnetotail from Juno MAG data against a baseline lobe field model. Data from the Juno Waves instrument also show activation of broadband kilometric (bKOM) emissions during the arrival of the shock, a feature that has previously been observed during compression events. Therefore this is the first time we can fully analyze the morphological variability during the evolution of a shock. Wavelet transforms and Rayleigh testing are used to search for statistically significant quasi‐periodic pulsations (QPPs) of the X‐ray emissions in the data set, and find significant QPPs with periods of 25–26 min for the northern auroral X‐rays.

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“…5 These Solar System bodies produce X-ray emissions that LEM will observe from scattering of solar photons, charge exchange interactions, fluorescence from solid surfaces and atmospheres, and continuum emissions through bremsstrahlung and inverse Compton scattering. [6][7][8][9][10][11][12][13] The low-energy sensitivity of LEM will test long-standing theoretical models and open new windows into these familiar worlds. 5 Thermal loading and loss of energy resolution and shifts in absolute energy scale could adversely affect much of this science, especially where accurate Doppler shift velocities or thermal broadening measurements are crucial, such as in studies of stellar flares and CMEs, in massive star winds, and in precipitating ions in planetary aurorae.…”

Section: Heat Loadmentioning

confidence: 99%

“…These Solar System bodies produce X-ray emissions that LEM will observe from scattering of solar photons, charge exchange interactions, fluorescence from solid surfaces and atmospheres, and continuum emissions through bremsstrahlung and inverse Compton scattering 6 – 13 The low-energy sensitivity of LEM will test long-standing theoretical models and open new windows into these familiar worlds 5 …”

Section: Introductionmentioning

confidence: 99%

Extending the high-resolution X-ray spectroscopy of Line Emission Mapper to UV/optically-bright sources

Drake,

Bandler,

Barbera

et al. 2024

J. Astron. Telesc. Instrum. Syst.

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The Line Emission Mapper X-ray Probe-class mission concept is based on a microcalorimeter array tuned to energies in the range 0.1 to 2 keV. The study of cosmic ecosystems defines the directed portion of the Line Emission Mapper (LEM) mission, thus LEM has been optimized for observations of diffuse X-ray-emitting gas, largely with very low surface brightness. To broaden the range of targets that general observers can study with LEM, we have investigated the particular needs for UV/optical bright stars and solar-system objects. X-ray microcalorimeters are susceptible to degraded energy resolution that can result from thermal noise from residual UV, optical, and IR radiation. Using the present baseline design of the microcalorimeter thermal filters, we compute the UV-IR loading expected from bright stars over the effective temperature range 3500 to 39,000 K and from solar-system objects. The dominant leak of out-of-band energy is in the far-UV around 1500 Å, with a secondary peak of throughput around 4000 Å. For stars with magnitudes V < 10 and for all solar-system planets as well as the Moon, the loading is significant, indicating that additional UV/optical blocking is essential if bright objects are to be observed. We have investigated the efficacy of several filter options for opticalblocking filters on the LEM filter wheel, demonstrating that new technology development is not necessary to open up many of these classes of objects to investigation with the high spectral resolution of LEM.

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X-Ray Emissions from the Jovian System

Cited by 6 publications

References 130 publications

Identifying the Variety of Jovian X‐Ray Auroral Structures: Tying the Morphology of X‐Ray Emissions to Associated Magnetospheric Dynamics

Identifying the Variety of Jovian X‐Ray Auroral Structures: Tying the Morphology of X‐Ray Emissions to Associated Magnetospheric Dynamics

Long Exposure Chandra X‐Ray Observation of Jupiter's Auroral Emissions During Juno Plasmasheet Encounters in September 2021

Extending the high-resolution X-ray spectroscopy of Line Emission Mapper to UV/optically-bright sources

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