Jupiter Science Enabled by ESA's Jupiter Icy Moons Explorer.

ESA's Jupiter Icy Moons Explorer (JUICE) will provide a detailed investigation of the Jovian system in the 2030s, combining a suite of state-of-the-art instruments with an orbital tour tailored to maximise observing opportunities. We review the Jupiter science enabled by the JUICE mission, building on the legacy of discoveries from the Galileo, Cassini, and Juno missions, alongside ground- and space-based observatories. We focus on remote sensing of the climate, meteorology, and chemistry of the atmosphere and auroras from the cloud-forming weather layer, through the upper troposphere, into the stratosphere and ionosphere.

Comparing Jupiter's Equatorial X-Ray Emissions With Solar X-Ray Flux Over 19 Years of the Chandra Mission.

We present a statistical study of Jupiter's disk X-ray emissions using 19 years of Chandra X-Ray Observatory (CXO) observations. Previous work has suggested that these emissions are consistent with solar X-rays elastically scattered from Jupiter's upper atmosphere. We showcase a new pulse invariant (PI) filtering method that minimizes instrumental effects which may produce unphysical trends in photon counts across the nearly two-decade span of the observations.

Magnetosphere-Ionosphere-Thermosphere Coupling Study at Jupiter Based on Juno's First 30 Orbits and Modeling Tools.

The dynamics of the Jovian magnetosphere is controlled by the interplay of the planet's fast rotation, its solar-wind interaction and its main plasma source at the Io torus, mediated by coupling processes involving its magnetosphere, ionosphere, and thermosphere. At the ionospheric level, these processes can be characterized by a set of parameters including conductances, field-aligned currents, horizontal currents, electric fields, transport of charged particles along field lines including the fluxes of electrons precipitating into the upper atmosphere which trigger auroral emissions, and the particle and Joule heating power dissipation rates into the upper atmosphere. Determination of these key parameters makes it possible to estimate the net transfer of momentum and energy between Jovian upper atmosphere and equatorial magnetosphere.

Jupiter's Low-Altitude Auroral Zones: Fields, Particles, Plasma Waves, and Density Depletions.

The Juno spacecraft's polar orbits have enabled direct sampling of Jupiter's low-altitude auroral field lines. While various data sets have identified unique features over Jupiter's main aurora, they are yet to be analyzed altogether to determine how they can be reconciled and fit into the bigger picture of Jupiter's auroral generation mechanisms. Jupiter's main aurora has been classified into distinct "zones", based on repeatable signatures found in energetic electron and proton spectra.

Jupiter's X-Ray and UV Dark Polar Region.

We present 14 simultaneous Chandra X-ray Observatory (CXO)-Hubble Space Telescope (HST) observations of Jupiter's Northern X-ray and ultraviolet (UV) aurorae from 2016 to 2019. Despite the variety of dynamic UV and X-ray auroral structures, one region is conspicuous by its persistent absence of emission: the dark polar region (DPR). Previous HST observations have shown that very little UV emission is produced by the DPR.

Closed Fluxtubes and Dispersive Proton Conics at Jupiter's Polar Cap.

Two distinct proton populations are observed over Jupiter's southern polar cap: a ∼1 keV core population and ∼1-300 keV dispersive conic population at 6-7 R planetocentric distance. We find the 1 keV core protons are likely the seed population for the higher-energy dispersive conics, which are accelerated from a distance of ∼3-5 R. Transient wave-particle heating in a "pressure-cooker" process is likely responsible for this proton acceleration.

Charon's refractory factory.

We combine novel laboratory experiments and exospheric modeling to reveal that "dynamic" Ly-α photolysis of Plutonian methane generates a photolytic refractory distribution on Charon that increases with latitude, consistent with poleward darkening observed in the New Horizons images. The flux ratio of the condensing methane to the interplanetary medium Ly-α photons, φ, controls the distribution and composition of Charon's photoproducts. Mid-latitude regions are likely to host complex refractories emerging from low-φ photolysis, while high-φ photolysis at the polar zones primarily generate ethane.

Revealing the source of Jupiter's x-ray auroral flares.

Jupiter's rapidly rotating, strong magnetic field provides a natural laboratory that is key to understanding the dynamics of high-energy plasmas. Spectacular auroral x-ray flares are diagnostic of the most energetic processes governing magnetospheres but seemingly unique to Jupiter. Since their discovery 40 years ago, the processes that produce Jupiter's x-ray flares have remained unknown.

The solar nebula origin of (486958) Arrokoth, a primordial contact binary in the Kuiper Belt.

The New Horizons spacecraft's encounter with the cold classical Kuiper Belt object (486958) Arrokoth (provisional designation 2014 MU) revealed a contact-binary planetesimal. We investigated how Arrokoth formed and found that it is the product of a gentle, low-speed merger in the early Solar System. Its two lenticular lobes suggest low-velocity accumulation of numerous smaller planetesimals within a gravitationally collapsing cloud of solid particles.

The geology and geophysics of Kuiper Belt object (486958) Arrokoth.

The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, is composed of primitive objects preserving information about Solar System formation. In January 2019, the New Horizons spacecraft flew past one of these objects, the 36-kilometer-long contact binary (486958) Arrokoth (provisional designation 2014 MU). Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters in diameter) within a radius of 8000 kilometers.

Color, composition, and thermal environment of Kuiper Belt object (486958) Arrokoth.

The outer Solar System object (486958) Arrokoth (provisional designation 2014 MU) has been largely undisturbed since its formation. We studied its surface composition using data collected by the New Horizons spacecraft. Methanol ice is present along with organic material, which may have formed through irradiation of simple molecules.

Jovian Injections Observed at High Latitude.

The polar orbit of Juno at Jupiter provides a unique opportunity to observe high-latitude energetic particle injections. We measure energy-dispersed impulsive injections of protons and electrons. Ion injection signatures are just as prevalent as electron signatures, contrary to previous equatorial observations.

Pluto's Interaction With Energetic Heliospheric Ions.

Pluto energies of a few kiloelectron volts and suprathermal ions with tens of kiloelectron volts and above. We measure this population using the Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument on board the New Horizons spacecraft that flew by Pluto in 2015. Even though the measured ions have gyroradii larger than the size of Pluto and the cross section of its magnetosphere, we find that the boundary of the magnetosphere is depleting the energetic ion intensities by about an order of magnitude close to Pluto.

Initial results from the New Horizons exploration of 2014 MU, a small Kuiper Belt object.

The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU, a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation.

Probing Jovian Broadband Kilometric Radio Sources Tied to the Ultraviolet Main Auroral Oval With Juno.

Observations of Jovian broadband kilometric (bKOM) radiation and ultraviolet (UV) auroras were acquired with the Waves and Juno-UVS instruments for ∼2 hr over the northern and southern polar regions during Juno's perijoves 4, 5, and 6 passes (PJ4, PJ5, and PJ6). During all six time periods, Juno traversed auroral magnetic field lines connecting to the UV main auroral ovals, matching the estimates of bKOM radio source footprints. The localized bKOM radio sources for the PJ4 north pass map to magnetic field lines having distances of 10 to 12 Jovian radii (R ) at the magnetic equator, whereas the extended bKOM radio sources for the other events map to field lines extending to 20-61 R .

Comparing Electron Energetics and UV Brightness in Jupiter's Northern Polar Region During Juno Perijove 5.

We compare electron and UV observations mapping to the same location in Jupiter's northern polar region, poleward of the main aurora, during Juno perijove 5. Simultaneous peaks in UV brightness and electron energy flux are identified when observations map to the same location at the same time. The downward energy flux during these simultaneous observations was not sufficient to generate the observed UV brightness; the upward energy flux was.

Upper Eyelid Blepharoplasty: A Novel Method to Predict and Improve Outcomes.

Background: In some upper eyelid blepharoplasties, maximal skin removal may not result in desired outcomes; raising crease height can therefore be considered. Currently, there is no method to determine the amount of skin to be excised and/or crease elevation required to achieve a specific outcome.

Objective: This study extrapolated an equation to determine amount of skin excision and/or lid crease elevation needed to achieve a specific eyelid margin to fold distance (MFD).

New Insights into the Glycosylation Steps in the Biosynthesis of Sch47554 and Sch47555.

Sch47554 and Sch47555 are antifungal compounds from Streptomyces sp. SCC-2136. The availability of the biosynthetic gene cluster made it possible to track genes that encode biosynthetic enzymes responsible for the structural features of these two angucyclines.

Juno-UVS approach observations of Jupiter's auroras.

Juno ultraviolet spectrograph (UVS) observations of Jupiter's aurora obtained during approach are presented. Prior to the bow shock crossing on 24 June 2016, the Juno approach provided a rare opportunity to correlate local solar wind conditions with Jovian auroral emissions. Some of Jupiter's auroral emissions are expected to be controlled or modified by local solar wind conditions.

Discrete and broadband electron acceleration in Jupiter's powerful aurora.

The most intense auroral emissions from Earth's polar regions, called discrete for their sharply defined spatial configurations, are generated by a process involving coherent acceleration of electrons by slowly evolving, powerful electric fields directed along the magnetic field lines that connect Earth's space environment to its polar regions. In contrast, Earth's less intense auroras are generally caused by wave scattering of magnetically trapped populations of hot electrons (in the case of diffuse aurora) or by the turbulent or stochastic downward acceleration of electrons along magnetic field lines by waves during transitory periods (in the case of broadband or Alfvénic aurora). Jupiter's relatively steady main aurora has a power density that is so much larger than Earth's that it has been taken for granted that it must be generated primarily by the discrete auroral process.

Jupiter's magnetosphere and aurorae observed by the Juno spacecraft during its first polar orbits.

The Juno spacecraft acquired direct observations of the jovian magnetosphere and auroral emissions from a vantage point above the poles. Juno's capture orbit spanned the jovian magnetosphere from bow shock to the planet, providing magnetic field, charged particle, and wave phenomena context for Juno's passage over the poles and traverse of Jupiter's hazardous inner radiation belts. Juno's energetic particle and plasma detectors measured electrons precipitating in the polar regions, exciting intense aurorae, observed simultaneously by the ultraviolet and infrared imaging spectrographs.

The impact of an ICME on the Jovian X-ray aurora.

We report the first Jupiter X-ray observations planned to coincide with an interplanetary coronal mass ejection (ICME). At the predicted ICME arrival time, we observed a factor of ∼8 enhancement in Jupiter's X-ray aurora. Within 1.

The formation of Charon's red poles from seasonally cold-trapped volatiles.

A unique feature of Pluto's large satellite Charon is its dark red northern polar cap. Similar colours on Pluto's surface have been attributed to tholin-like organic macromolecules produced by energetic radiation processing of hydrocarbons. The polar location on Charon implicates the temperature extremes that result from Charon's high obliquity and long seasons in the production of this material.