The computation of compressible flows at all Mach numbers is a very challenging problem. An efficient numerical method for solving this problem needs to have shock-capturing capability in the high Mach number regime, while it can deal with stiffness and accuracy in the low Mach number regime. This paper designs a high order semi-implicit weighted compact nonlinear scheme (WCNS) for the all-Mach isentropic

In this paper, we introduce the discrete Maxwellian equilibrium distribution function for incompressible flow and force term into the two-stage third-order Discrete Unified Gas-Kinetic Scheme (DUGKS) for simulating low-speed turbulent flows. The Wall-Adapting Local Eddy-viscosity (WALE) and Vreman sub-grid models for Large-Eddy Simulations (LES) of turbulent flows are coupled within the present framework

Experimental measurements of density by X‐ray absorption and of P‐wave velocity by ultrasonic techniques of liquid Fe‐(<17wt%)Si‐(<4.5wt%)C alloys at pressures up to 5.8 GPa are presented. These data are used to construct an Fe‐Si‐C liquid mixing model and to characterize interior structure models of Mercury with liquid outer core composed of Fe‐Si‐C. The interior structure models are constrained by

In this work, we investigate the Earth–Moon system, as modeled by the planar circular restricted three-body problem, and relate its dynamical properties to the underlying structure associated with specific invariant manifolds. We consider a range of Jacobi constant values for which the neck around the Lagrangian point \(L_1\) is always open, but the orbits are bounded due to Hill stability. First,

We present an approach to estimate an upper bound for the impact probability of a potentially hazardous asteroid when part of the force model depends on unknown parameters whose statistical distribution needs to be assumed. As case study, we consider Apophis’ risk assessment for the 2036 and 2068 keyholes based on information available as of 2013. Within the framework of epistemic uncertainties, under

In this paper, we develop an analytical stability criterion for a five-body symmetrical system, called the Caledonian Symmetric Five-Body Problem (CS5BP), which has two pairs of equal masses and a fifth mass located at the centre of mass. The CS5BP is a planar problem that is configured to utilise past–future symmetry and dynamical symmetry. The introduction of symmetries greatly reduces the dimensions

We study the reduction and regularization processes of perturbed Keplerian systems from an astronomical point of view. Our approach connects axially symmetric perturbed 4-DOF oscillators with Keplerian systems, including the case of rectilinear solutions. This is done through a preliminary reduction recently studied by the authors. Then, the reduction program continues by removing the Keplerian energy

In October 2014, the close encounter between Mars and comet Siding Spring produced a transient ionized layer in the upper atmosphere composed primarily of Mg+ and Fe+ ions. The layer was detected by instruments on three spacecraft, including the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) on Mars Express. Analyses of the MARSIS data indicated the transient layer persisted up

High‐obliquity excursions on Mars are hypothesized to have redistributed water from the poles to nourish mid‐latitude glaciers. Evidence of this process is provided by different types of viscous flow features (ice‐rich deposits buried beneath sediment mantle) located there today, including lobate debris aprons (LDAs). During high‐obliquity extremes, ice may have persisted even nearer the equator, as

We have analyzed medium‐resolution (FWHM = 1.2 nm) middle‐ultraviolet (MUV; 180‐ 280 nm) laboratory emission spectra of CO excited by electron impact at 15, 20, 40, 50 and 100 eV under single‐scattering conditions at 300 K. The MUV emission spectra at 100 eV contain the Cameron Bands (CB) CO(a 3Π → X 1Σ+), the Fourth Positive Group (4PG) CO(A 1Π → X 1Σ+), and the First Negative Group (1NG) CO+(B 2Σ+

Martian meteorites are the only direct samples from Mars, thus far. Currently, there are a total of 262 individual samples originating from at least 11 ejection events. Geochemical analyses, through techniques that are also used on terrestrial rocks, provide fundamental insights into the bulk composition, differentiation and evolution, mantle heterogeneity, and role of secondary processes, such as

The first human missions on Mars will likely involve several astrobiology‐driven science operations, at sites with high biosignature preservation potential. Here we present a study of the radiation environment induced by Galactic Cosmic Rays and Solar Energetic Particles at Oxia Planum (landing site of the ESAs ExoMars 2022mission) and at two different locations in Mawrth Vallis, using the Monte Carlo

The geologic analysis of lunar tectonic and co‐existing mass wasting features provides important insights into seismicity, seismic ground motion and the seismic risk of the landed missions. Hence, we performed a detailed geologic mapping of tectonic features and co‐seismic boulder avalanches present at the 930‐km‐diameter lunar Orientale basin. We traced 6,869 boulder falls at 141 sites along the basin

Studying the atmospheric Planetary Boundary Layer (PBL) is crucial to understand the climate of a planet. The meteorological measurements by the instruments onboard InSight at a latitude of 4.5⁰ N make a uniquely rich dataset to study the active turbulent dynamics of the daytime PBL on Mars. Here we use the high‐sensitivity continuous pressure, wind, temperature measurements in the first 400 sols of

In this work, we study the dynamics of particles around Bennu. The goal is to understand the stability, evolution, and final outcome of the simulated particles around the asteroid. According to the results, the particle sizes can be divided into two main groups depending on their behavior. Particles smaller than a centimeter are quickly removed from the system by solar radiation pressure, while the

An understanding of the current state of the Martian North Polar Residual Cap (NPRC) is needed to understand the North Polar Layered Deposits (NPLD) as a whole and the recent climate history of Mars. We investigate the evolution of small‐scale (∼10s of m) surface topography on the NPRC using an insolation‐driven ice accumulation/ablation model. We apply a coupled thermal and atmospheric model that

A high proportion of non‐crystalline (X‐ray‐amorphous) components has been found in all samples analyzed by CheMin on the Curiosity rover at Gale crater on Mars, and such X‐ray‐amorphous components probably occur at all sites that have been investigated thus far by landers and rovers. The amorphous material at Gale crater is rich in volatiles (S, Cl, and H2O), as indicated by other science payload

Ceres has an abundance of long runout landslides with more slides near the poles. Here we simulate these landslides using a discrete element model. Our simulations indicate that long runout landslides on Ceres do not require the presence of fluid or slippery ice to explain their mobility. We find that lower fall heights and larger volumes lead to increased slide mobility while the relatively low surface

We study the inter‐annual variability of atmospheric gravity waves (GWs) in the Martian thermosphere and their relation to the background temperatures using Ar densities measured by NGIMS/MAVEN. The amplitudes and wavelengths of the GWs are extracted from the neutral density perturbations in the inbound segment of the MAVEN orbit. The GW amplitudes predominantly lie between 5% and 10 % and are mostly

Accuracy of unstructured finite volume discretization is greatly influenced by the gradient reconstruction. For the commonly used k-exact reconstruction method, the cell centroid is always chosen as the reference point to formulate the reconstructed function. But in some practical problems, such as the boundary layer, cells in this area are always set with high aspect ratio to improve the local field

Allophane, a common component on Earth and a probable constituent of the amorphous component on Mars, is closely associated with Fe in the form of structural Fe and/or iron (oxyhydr)oxide coatings. However, until now, the formation and evolution of allophane as products of environmental Fe concentrations have rarely been studied. We investigated allophane precipitation from gels with different Fe/(Fe+Al)

Arsinoes and Pyrrhae Chaos are two adjacent chaotic terrains located east of Valles Marineris and west of Arabia Terra, on Mars. In this work we produced a morpho‐stratigraphic map of the area, characterized by a volcanic bedrock disrupted into polygonal mesas and knobs (Chaotic Terrain Unit) and two non‐disrupted units. The latter present a spectral variation, likely associated with hydrated minerals

The South Polar Terrain (SPT) of Enceladus is a site with eruptions of gas and water ice particle plumes, which indicate internal geodynamic activity. These eruptions are located along a series of tectonic structures, i.e. the Tiger Stripe Fractures (TSF), which are composed of regularly spaced, linear depressions. The SPT is surrounded by sinuous chains of ridges and troughs (the Marginal Zone). To

Planets intermediate in size between the Earth and Neptune, and orbiting closer to their host stars than Mercury does the Sun, are the most common type of planet revealed by exoplanet surveys over the last quarter century. Results from NASA's Kepler mission have revealed a bimodality in the radius distribution of these objects, with a relative underabundance of planets between 1.5 and 2.0 R⊕ This bimodality

Diverse polygonal patterned grounds are found to occur in the Eridania basin system (a set of connecting irregular‐shaped depressions interpreted as a paleolake basin system) located in the martian highland region between Terra Cimmeria and Sirenum. We here use multiple sets of imagery to document diverse polygonal patterned grounds in the fluvio‐lacustrine deposits of the northern Eridania basin,

Previous studies have shown that Mt. Sharp has stratigraphic variation in mineralogy that may record a global transition from a climate more conducive to clay mineral formation to one marked by increased sulfate production. To better understand how small‐scale observations along the traverse path of NASA's Curiosity rover might be linked to such large‐scale processes, it is necessary to understand

Moray Sinus is an estuary located at the northern end of Titan's Kraken Mare. The Cassini RADAR altimeter acquired three segments over this mare during the T104 flyby of Titan, on August 21st, 2014. Herein, we present a detailed analysis of the received echoes. Some of these waveforms exhibit a reflection from the seafloor, from up to 85‐81+28 m of depth (1σ error). Monte‐Carlo simulations have been

The dayside N2/CO2 at 140 km altitude in the Martian thermosphere has been investigated by the Imaging UltraViolet Spectrograph (IUVS) aboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft during the period from October 2014 to May 2018. We find that N2/CO2 at 140 km altitude varies significantly in the range of 0.02 to 0.20 and shows a seasonal sinusoidal trend. The higher value appears

The Mars Science Laboratory rover (Curiosity) has monitored the line‐of‐sight extinction within Gale Crater since mission sol 100 (16 November 2012, MY 31 Ls 208°) with Navcam and since mission sol 1,187 (8 December 2015, MY 33 Ls 79°) with the color imager, Mastcam. This work reports 1,375 sols (>2 MYs) of line‐of‐sight extinction monitoring within Gale Crater with Mastcam and updates the Navcam line‐of‐sight

The Solar System is home to a cloud of dust that orbits the Sun and makes its presence known by virtue of scattered light (Zodiacal Light) that can be seen after dusk and before dawn. Within this cloud are bands of dust orbiting near the ecliptic plane, evidenced by an excess of scattered light at discrete ecliptic latitudes. Dedicated dust detectors borne by spacecraft in transit of the solar system

Processes that occur beneath a planetary surface control the spatial distribution of volcanic features in a volcanic zone. Volcanic vents frequently form clusters and alignments controlled by the lithospheric structure and the stress field. Previous works have determined the influence of stress at different scales in a volcanic area. In this work, we analyze the distribution of volcanic vents on top

Geological conditions play a significant role in prebiotic/abiotic organic chemistry, especially when reactive minerals are present. Previous studies of the prebiotic synthesis of amino acids and other products in mineral‐containing systems have shown that a diverse array of compounds can be produced, depending on the experimental conditions. However, these previous experiments have not simulated the

Venus is currently characterized by stagnant‐lid mantle convection, but could have previously experienced episodes of global resurfacing due to lithospheric overturn. Using numerical models of Venus's interior, we attempt to explain Venus's surface characteristics in the context of interior evolution and to understand how Venus's tectonic history has diverged from Earth's. For both the stagnant‐ and

Experimental measurements of collision‐induced absorption (CIA) cross‐sections for CO2‐H2 and CO2‐CH4 complexes were performed using Fourier transform spectroscopy over a spectral range of 150‐475 cm−1 and a temperature range of 200‐300 K. These experimentally derived CIA cross‐sections agree with the spectral range of the calculation by Wordsworth et al. 2017, however the amplitude is half of what

The Visible‐Infrared Mapping Spectrometer (VIR) on board the Dawn spacecraft revealed that aqueous secondary minerals – Mg‐phyllosilicates, NH4‐bearing phases, and Mg/Ca carbonates – are ubiquitous on Ceres. Ceres’ low reflectance requires dark phases, which were assumed to be amorphous carbon and/or magnetite (∼80 wt.%). In contrast, the Gamma Ray and Neutron Detector (GRaND) constrained the abundances

Seafloor cratering is an important process that records the impact history of the Earth, affects projectile survivability, and determines the mass of ejecta from benthic rock that is transported to the atmosphere. We report experimental hypervelocity impacts of chondrite and other projectiles (olivine, stainless‐steel, polycarbonate) on a water‐covered iron target to derive a scaling relationship for

The Jovian InfraRed Auroral Mapper (JIRAM) on board the NASA Juno spacecraft is a dual‐band imager and spectrometer in the 2‐5 μm range with 9‐nm spectral sampling, primarily designed to study the Jovian atmosphere and aurorae. In addition to these goals, JIRAM is used to obtain images and spectra of the Galilean satellites, every time the spacecraft attitude is favorable. Here we present JIRAM images

It is challenge to distinguish the various lunar glasses, which are characterized by complex origin (volcanic eruption or impact melting) and large compositional variation (picritic, basaltic, or feldspathic). In this work, we present the Raman spectra (200 to 1500 cm−1) of a series of lunar glasses (i.e., pyroclastic glasses, mare impact glasses, and highland impact glasses), which were recognized

Evidence for tectonic activity on Titan is provided by the presence of eroded mountain ranges. Xanadu is an equatorial region of Titan characterized by a complex topography, even though overall it has a lower average elevation compared to its surroundings. We investigated Xanadu's southwestern margin, a part of the region composed of heavily eroded and rugged terrains to the north and east, and of

During 2018 and 2019, the Mars Science Laboratory Curiosity rover investigated the chemistry, morphology, and stratigraphy of Vera Rubin ridge (VRR). Using orbital data from the Compact Reconnaissance Imaging Spectrometer for Mars, scientists attributed the strong 860 nm signal associated with VRR to the presence of red crystalline hematite. However, Mastcam multispectral data and CheMin X‐ray diffraction

For internal flow with supersonic inflow boundary conditions, a complicated oblique shock reflection may occur. Different from the planar shock reflection problem, where the shape of the incident shock can be a straight line, the shape of the incident shock wave in the inward-facing axisymmetric shock reflection in steady flow is an unknown curve. In this paper, a simple theoretical approach is proposed

Rubble pile asteroids such as (162173) Ryugu have large bulk porosities, which are believed to result from void spaces in between the constituent boulders (macroporosity) as well as void spaces within the boulders themselves (microporosity). In general, both macroporosity and microporosity are estimated based on comparisons between the asteroid bulk density and both the bulk and grain density of meteorite

Investigating the space weathering of the Martian moon Phobos represents an important step towards understanding the development from its origin to its present‐day appearance. Depending on Phobos' orbital position, its surface is continuously sputtered by the solar wind and planetary ions that originate in the Martian atmosphere. Based on MAVEN measurements, it has been proposed that sputtering by

Rover data can provide important constraints on the possible origin of wind‐related martian features that have been termed ‘Transverse Aeolian Ridges’ (TARs). The large aeolian bedform traversed by Curiosity at Dingo Gap has a planform and albedo similar to members of nearby TAR fields, so that the crossing at Dingo Gap revealed the surface characteristics of a small TAR. Mars Hand Lens Imager (MAHLI)

Early gravity measurements performed by the Juno spacecraft determined Jupiter's low‐degree gravity harmonics, including the first estimate of the planet's north‐south asymmetric field. The retrieved information was used to infer that the strong zonal winds visible at the cloud tops must extend down a few thousand kilometers, where they are suppressed in the deep interior. The next frontier for the

Images from the Mars Science Laboratory (MSL) mission of lacustrine sedimentary rocks of Vera Rubin ridge on “Mt. Sharp” in Gale crater, Mars, have shown stark color variations from red to purple to gray. These color differences crosscut stratigraphy and are likely due to diagenetic alteration of the sediments after deposition. However, the chemistry and timing of these fluid interactions is unclear

The properties of Martian aerosols are an integral part of the planetary climatology. Global dust storms (GDS) significantly alter spatial and vertical distributions of dust and water ice aerosols and their microphysical properties. We explored the 2018/Martian year 34 GDS with the Atmospheric Chemistry Suite instrument onboard the ESA‐Roscosmos Trace Gas Orbiter mission. Solar occultation observations

To assess the viability of sulfide liquid saturation during crystallization of the lunar magma ocean (LMO), we present a new data set describing both the sulfur (S) concentration at sulfide liquid saturation (SCSS) and sulfide liquid‐silicate melt partition coefficients of many trace elements for various differentiated lunar magmas at lunar‐relevant conditions. Using these parameterizations, we model

Sulfur dioxide is a radiatively and chemically important trace gas in the atmosphere of Venus and its abundance at the cloud tops has been observed to vary on interannual to decadal timescales. This variability is thought to come from changes in the strength of convection which transports sulfur dioxide to the cloud tops, although the dynamics behind such convective variability are unknown. Here, we

Eleven transient bright flashes were detected in Jupiter's atmosphere using the ultraviolet spectrograph instrument on the Juno spacecraft. These bright flashes are only observed in a single spin of the spacecraft and their brightness decays exponentially with time, with a duration of ∼1.4 ms. The spectra are dominated by H2 Lyman band emission and based on the level of atmospheric absorption, we estimate

This paper presents a derivative-free method for computing approximate solutions to the uncertain Lambert problem (ULP) and the reachability set problem (RSP) while utilizing higher-order sensitivity matrices. These sensitivities are analogous to the coefficients of a Taylor series expansion of the deterministic solution to the ULP and RSP, and are computed in a derivative-free and computationally

When an asteroid has a few observations over a short time span the information contained in the observational arc could be so little that a full orbit determination may be not possible. One of the methods developed in recent years to overcome this problem is based on the systematic ranging and combined with the Admissible Region theory to constrain the poorly-determined topocentric range and range-rate

Hephaestus Fossae are a system of northwest trending troughs west of the Elysium Mons volcanic construct on Mars. Pitted cones present in the fossae region have previously been interpreted as both igneous and mud volcanism products based on morphometry and morphology observations. We take advantage of multiple orbital remote sensing datasets to assess the validity of these hypotheses. Newly examined

Much of the water that once flowed on the surface of Mars was lost to space long ago, and the total amount lost remains unknown. Clues to the amount lost can be found by studying hydrogen (H) and its isotope deuterium (D), which are produced when atmospheric water molecules H2O and HDO dissociate. The difference in escape efficiencies of H and D (which leads to an enhanced D/H ratio) is referred to

Mars’ planet‐encircling or global dust storms are an iconic and enigmatic feature of the Red Planet. Occurring every few Mars Years, on average, they are a stochastic process in the otherwise largely repeatable annual cycle of martian weather. In 2018 (Mars Year 34 in the calendar of Clancy et al. [2000]), an international fleet of spacecraft–6 orbiters and 2 rovers–observed the most recent global

[Among the geological features revealed by the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry and Ranging) mission on the surface of Mercury, hollows are the most surprising and least understood. Possibly related to volatile components, hollows are small depressions, surrounded by bright halos and are not observed on any other surfaces in our Solar System. Previous analysis of multi‐spectral

The Alpha Particle X‐ray Spectrometer (APXS) on the rover Curiosity has analyzed the composition of geologic materials along a >20‐kilometer traverse in Gale crater on Mars. The APXS dataset after 6.5 Earth years (2301 sols) includes 712 analyses of soil, sand, float, bedrock, and drilled/scooped fines. We present the APXS results over this duration and provide stratigraphic context for each target

We present a new class of seismic signals that are recorded by the seismometer placed on the surface of Mars as part of the NASA InSight mission. The signals, termed super high frequency (SF) events, are of short duration (∼20 s), with high‐frequency energy between ∼5–30 Hz that is dominant on the horizontal components, and are often comparable in amplitude. For detection and characterization of SF

No abstract is available for this article.

Gravity wave (GW) activity in the lower and middle atmosphere of Mars during the global dust storm of 2018 has been studied for the first time using a high‐resolution (GW‐resolving) general circulation model. Dust storm simulations were compared with those utilizing the climatological distribution of dust in the absence of storms. Both scenarios are based on observations of the dust optical depth by