A source of very energetic oxygen located in Jupiter's inner radiation belts.

Jupiter hosts the most hazardous radiation belts of our solar system that, besides electrons and protons, trap an undetermined mix of heavy ions. The details of this mix are critical to resolve because they can reveal the role of Jupiter’s moons relative to other less explored energetic ion sources. Here, we show that with increasing energy and in the vicinity of Jupiter’s moon Amalthea, the belts’ ion composition transitions from sulfur- to oxygen-dominated due to a local source of ≳50 MeV/nucleon oxygen.

Potential Pitfalls in the Analysis and Structural Interpretation of Seismic Data from the Mars InSight Mission.

The Seismic Experiment for Interior Structure (SEIS) of the mission to Mars, has been providing direct information on Martian interior structure and dynamics of that planet since it landed. Compared to seismic recordings on Earth, ground motion measurements acquired by SEIS on Mars are made under dramatically different ambient noise conditions, but include idiosyncratic signals that arise from coupling between different sensors and spacecraft components. This work is to synthesize what is known about these signal types, illustrate how they can manifest in waveforms and noise correlations, and present pitfalls in structural interpretations based on standard seismic analysis methods.

GAUSS - genesis of asteroids and evolution of the solar system: A sample return mission to Ceres.

The goal of Project GAUSS (Genesis of Asteroids and evolUtion of the Solar System) is to return samples from the dwarf planet Ceres. Ceres is the most accessible candidate of ocean worlds and the largest reservoir of water in the inner Solar System. It shows active volcanism and hydrothermal activities in recent history.

Terrestrial planet formation from lost inner solar system material.

Two fundamentally different processes of rocky planet formation exist, but it is unclear which one built the terrestrial planets of the solar system. They formed either by collisions among planetary embryos from the inner solar system or by accreting sunward-drifting millimeter-sized “pebbles” from the outer solar system. We show that the isotopic compositions of Earth and Mars are governed by two-component mixing among inner solar system materials, including material from the innermost disk unsampled by meteorites, whereas the contribution of outer solar system material is limited to a few percent by mass.

Improving Constraints on Planetary Interiors With PPs Receiver Functions.

Seismological constraints obtained from receiver function (RF) analysis provide important information about the crust and mantle structure. Here, we explore the utility of the free-surface multiple of the P-wave (PP) and the corresponding conversions in RF analysis. Using earthquake records, we demonstrate the efficacy of PPs-RFs before illustrating how they become especially useful when limited data is available in typical planetary missions.

Peering into lunar permanently shadowed regions with deep learning.

The lunar permanently shadowed regions (PSRs) are expected to host large quantities of water-ice, which are key for sustainable exploration of the Moon and beyond. In the near future, NASA and other entities plan to send rovers and humans to characterize water-ice within PSRs. However, there exists only limited information about the small-scale geomorphology and distribution of ice within PSRs because the orbital imagery captured to date lacks sufficient resolution and/or signal.

Thickness and structure of the martian crust from InSight seismic data.

A planet's crust bears witness to the history of planetary formation and evolution, but for Mars, no absolute measurement of crustal thickness has been available. Here, we determine the structure of the crust beneath the InSight landing site on Mars using both marsquake recordings and the ambient wavefield. By analyzing seismic phases that are reflected and converted at subsurface interfaces, we find that the observations are consistent with models with at least two and possibly three interfaces.

Upper mantle structure of Mars from InSight seismic data.

For 2 years, the InSight lander has been recording seismic data on Mars that are vital to constrain the structure and thermochemical state of the planet. We used observations of direct ( and ) and surface-reflected (, , , and ) body-wave phases from eight low-frequency marsquakes to constrain the interior structure to a depth of 800 kilometers. We found a structure compatible with a low-velocity zone associated with a thermal lithosphere much thicker than on Earth that is possibly related to a weak -wave shadow zone at teleseismic distances.

Habitability Models for Astrobiology.

Habitability has been generally defined as the capability of an environment to support life. Ecologists have been using Habitat Suitability Models (HSMs) for more than four decades to study the habitability of Earth from local to global scales. Astrobiologists have been proposing different habitability models for some time, with little integration and consistency among them, being different in function to those used by ecologists.

An overall view of temperature oscillations in the solar chromosphere with ALMA.

By direct measurements of the gas temperature, the Atacama Large Millimeter/submillimeter Array (ALMA) has yielded a new diagnostic tool to study the solar chromosphere. Here, we present an overview of the brightness-temperature fluctuations from several high-quality and high-temporal-resolution (i.e.

In Search for a Planet Better than Earth: Top Contenders for a Superhabitable World.

The fact that Earth is teeming with life makes it appear odd to ask whether there could be other planets in our galaxy that may be even more suitable for life. Neglecting this possible class of "superhabitable" planets, however, could be considered anthropocentric and geocentric biases. Most important from the perspective of an observer searching for extrasolar life is that such a search might be executed most effectively with a focus on superhabitable planets instead of Earth-like planets.

Impact heat driven volatile redistribution at Occator crater on Ceres as a comparative planetary process.

Hydrothermal processes in impact environments on water-rich bodies such as Mars and Earth are relevant to the origins of life. Dawn mapping of dwarf planet (1) Ceres has identified similar deposits within Occator crater. Here we show using Dawn high-resolution stereo imaging and topography that Ceres' unique composition has resulted in widespread mantling by solidified water- and salt-rich mud-like impact melts with scattered endogenic pits, troughs, and bright mounds indicative of outgassing of volatiles and periglacial-style activity during solidification.

Global maps of the magnetic field in the solar corona.

Understanding many physical processes in the solar atmosphere requires determination of the magnetic field in each atmospheric layer. However, direct measurements of the magnetic field in the Sun's corona are difficult to obtain. Using observations with the Coronal Multi-channel Polarimeter, we have determined the spatial distribution of the plasma density in the corona and the phase speed of the prevailing transverse magnetohydrodynamic waves within the plasma.

Numerical simulations help revealing the dynamics underneath the clouds of Jupiter.

Since its arrival at Jupiter in 2016, NASA’s Juno spacecraft has been performing high-precision measurement of the gravity and magnetic fields. When combined with numerical simulations, they provide a unique window to the dynamics in the planet’s deep atmosphere.

Impacts drive lunar rockfalls over billions of years.

Past exploration missions have revealed that the lunar topography is eroded through mass wasting processes such as rockfalls and other types of landslides, similar to Earth. We have analyzed an archive of more than 2 million high-resolution images using an AI and big data-driven approach and created the first global map of 136.610 lunar rockfall events.

Landslides on Ceres: Diversity and Geologic Context.

Landslides are among the most widespread geologic features on Ceres. Using data from Dawn's Framing Camera, landslides were previously classified based upon geomorphologic characteristics into one of three archetypal categories, Type 1(T1), Type 2 (T2), and Type 3 (T3). Due to their geologic context, variation in age, and physical characteristics, most landslides on Ceres are, however, intermediate in their morphology and physical properties between the archetypes of each landslide class.

Composition of cometary particles collected during two periods of the Rosetta mission: multivariate evaluation of mass spectral data.

The instrument COSIMA (COmetary Secondary Ion Mass Analyzer) onboard of the European Space Agency mission Rosetta collected and analyzed dust particles in the neighborhood of comet 67P/Churyumov-Gerasimenko. The chemical composition of the particle surfaces was characterized by time-of-flight secondary ion mass spectrometry. A set of 2213 spectra has been selected, and relative abundances for CH-containing positive ions as well as positive elemental ions define a set of multivariate data with nine variables.

Testing Flight-like Pyrolysis Gas Chromatography-Mass Spectrometry as Performed by the Mars Organic Molecule Analyzer Onboard the ExoMars 2020 Rover on Oxia Planum Analog Samples.

The Mars Organic Molecule Analyzer (MOMA) onboard the ExoMars 2020 rover (to be landed in March 2021) utilizes pyrolysis gas chromatography-mass spectrometry (GC-MS) with the aim to detect organic molecules in martian (sub-) surface materials. Pyrolysis, however, may thermally destroy and transform organic matter depending on the temperature and nature of the molecules, thus altering the original molecular signatures. In this study, we tested MOMA flight-like pyrolysis GC-MS without the addition of perchlorates on well-characterized natural mineralogical analog samples for Oxia Planum, the designated ExoMars 2020 landing site.

Non-spherical particles in optical tweezers: A numerical solution.

We present numerical methods for modeling the dynamics of arbitrarily shaped particles trapped within optical tweezers, which improve the predictive power of numerical simulations for practical use. We study the dependence of trapping on the shape and size of particles in a single continuous wave beam setup. We also consider the implications of different particle compositions, beam types and media.

Generation of solar spicules and subsequent atmospheric heating.

Spicules are rapidly evolving fine-scale jets of magnetized plasma in the solar chromosphere. It remains unclear how these prevalent jets originate from the solar surface and what role they play in heating the solar atmosphere. Using the Goode Solar Telescope at the Big Bear Solar Observatory, we observed spicules emerging within minutes of the appearance of opposite-polarity magnetic flux around dominant-polarity magnetic field concentrations.

A giant exoplanet orbiting a very-low-mass star challenges planet formation models.

Surveys have shown that super-Earth and Neptune-mass exoplanets are more frequent than gas giants around low-mass stars, as predicted by the core accretion theory of planet formation. We report the discovery of a giant planet around the very-low-mass star GJ 3512, as determined by optical and near-infrared radial-velocity observations. The planet has a minimum mass of 0.

Investigating the Effect of Perchlorate on Flight-like Gas Chromatography-Mass Spectrometry as Performed by MOMA on board the ExoMars 2020 Rover.

The Mars Organic Molecule Analyzer (MOMA) instrument on board ESA's ExoMars 2020 rover will be essential in the search for organic matter. MOMA applies gas chromatography-mass spectrometry (GC-MS) techniques that rely on thermal volatilization. Problematically, perchlorates and chlorates in martian soils and rocks become highly reactive during heating (>200°C) and can lead to oxidation and chlorination of organic compounds, potentially rendering them unidentifiable.

Local-time averaged maps of H emission, temperature and ion winds.

We present Keck-NIRSPEC observations of Saturn's [Formula: see text] aurora taken over a period of a month, in support of the Cassini mission's 'Grand Finale'. These observations produce two-dimensional maps of Saturn's [Formula: see text] temperature and ion winds for the first time. These maps show surprising complexity, with different morphologies seen in each night.