Sazuna/UAT_keywords huggingface dataset:
Activity-induced Near-infrared Spectral Variability at 29P/Schwassmann–Wachmann 1, 2017–2022. 29P/Schwassmann–Wachmann 1 (SW1) is both the first-discovered active Centaur and the most outburst-prone comet known. The nature of SW1's many outbursts, which regularly brighten the comet by 5 mag or more, and what processes power them has been of particular interest since SW1's discovery in the 1920s. In this paper, we present and model four epochs of low-resolution near-infrared spectroscopy of SW1 taken with the NASA Infrared Telescope Facility and Lowell Discovery Telescope between 2017 and 2022. This data set includes one large outburst, two periods of low activity ("quiescence" or "quiescent activity"), and one midsized outburst a few days after one of the quiescent observations. The two quiescent epochs appear similar in both spectral slope and modeled grain size distributions, but the two outbursts are significantly different. We propose that the two can be reconciled if smaller dust grains are accelerated more than larger ones, such that observations closer to the onset of an outburst are more sensitive to the finer-grained dust on the outside of the expanding cloud of material. These outbursts can thus appear very rapid, but there is still a period where the dust and gas are well coupled. We find no strong evidence of water-ice absorption features in any of our spectra, suggesting that the areal abundance of ice-dominated grains is less than 1%. We conclude with a discussion of future modeling and monitoring efforts that might be able to further advance our understanding of this object's complicated activity patterns.

Keywords: Ice spectroscopy, Comae, Coma dust
The Spin Zone: Synchronously and Asynchronously Rotating Land Planets Have Spectral Differences in Transmission. New observational facilities are beginning to enable insights into the three-dimensional (3D) nature of exoplanets. Transmission spectroscopy is the most widely used method for characterizing transiting temperate exoplanet atmospheres, but because it only provides a glimpse of the planet's limb and nightside for a typical orbit, its ability to probe 3D characteristics is still an active area of research. Here, we use the ROCKE-3D general circulation model to test the impact of synchronization state, a "low-order" 3D characteristic previously shown to drive differences in planetary phase curves, on the transmission spectrum of a representative super-Earth land planet across temperate-to-warm instellations (Sp = 0.8, 1, 1.25, 1.66, 2, 2.5, 3, 4, and 4.56 S⊕). We find that different synchronization states do display differences in their transmission spectra, primarily driven by clouds and humidity, and that the differences shrink or disappear in hotter regimes where water clouds are unable to condense (though our simulations do not consider haze formation). The small size of the feature differences and potential for degeneracy with other properties, like differing water content or atmospheric structure, mean that we do not specifically claim to have identified a single transmission diagnostic for synchronization state, but our results can be used for holistic spectrum interpretation and sample creation and suggest the need for more modeling in this area.

Keywords: Exoplanet atmospheric dynamics, Exoplanet atmospheric variability, Transmission spectroscopy, Exoplanet atmospheres, Exoplanet atmospheric structure
Laser-induced Breakdown Spectroscopy of Ice-regolith Mixtures: Implications for Measurements on Planetary Surfaces. Laser-induced breakdown spectroscopy (LIBS) is an analytical technique enabling in situ chemical analysis of planetary surfaces. Its use on the Mars Science Laboratory and Mars 2020 missions has demonstrated the potential for quantifying water in hydrated minerals, prompting investigations into its application for detecting and quantifying water ice in lunar regolith. Although promising results have been reported under vacuum conditions, previous measurements do not fully represent the range of physical forms that ice-regolith mixtures may take on the Moon. In this study, we use a scanning LIBS micro-analyzer to assess the main sources of signal variance and the response of the Hα emission line to 0–40 wt% water ice in two types of ice-regolith mixtures. We find that the primary factor influencing hydrogen emission is enhanced laser coupling with larger grains in wet or ice-cemented regolith due to increased cohesion. Emission from "cemented" ice-regolith mixtures exhibits increasing Hα intensity up to ∼15 wt%, followed by a decline attributed to water saturation. In contrast, emission from "discrete" ice-regolith mixtures shows no consistent Hα response in the 0–10 wt% range. Regression models trained on physically diverse mixtures reduce the rms error of predicted H2O content by 5.6% across the 0–40 wt% range. These results highlight the need for calibration using geologic materials that reflect grain size, porosity, and type of ice-regolith mixture. They also demonstrate the value of scanning LIBS technologies for identifying sources of signal variability in planetary applications.

Keywords: The Moon, Surface ices, Spectroscopy
Rare Phosphides and Nitrides in Igneous Clasts within Aqueously Altered Chondrites. Chondritic meteorites and their components provide us with the means to investigate the conditions and processes in the early solar system, including the delivery of bio-essential elements, such as phosphorus, to the early Earth. In this work, we report on three additional identifications of the rare phosphide mineral andreyivanovite (FeCrP) and the first identifications of the related phosphide allabogdanite ((Fe,Ni)2P) and the nitride carlsbergite (CrN) in carbonaceous chondrites. We investigated multiple clusters of individual clasts in the C2-ungrouped chondrites Tarda and Tagish Lake and a single clast bearing andreyivanovite in the CM2 chondrite Moapa Valley, more than doubling the previously known extraterrestrial occurrences of this mineral. In all three meteorites, andreyivanovite was identified in distinct clasts as elongated lathes set in a groundmass of phyllosilicate minerals. The related phosphide allabogdanite and the Cr-nitride carlsbergite, both of which are found in iron meteorites, were identified in association with andreyivanovite in Tarda, providing further evidence that andreyivanovite and its host clasts in meteorites originally formed by solidification from a melted precursor and survived subsequent aqueous alteration that formed the phyllosilicate groundmasses. Furthermore, the difficulty of detecting allabogdanite and andreyivanovite without dedicated surveys, combined with the high abundance of andreyivanovite-bearing clasts observed in Tarda and Tagish Lake, suggests that andreyivanovite may be more common than previously thought and may be an important phase in the delivery of phosphorus to the early Earth.

Keywords: Carbonaceous chondrites, Cosmochemistry, Asteroids
Characterizing the Radiative–Convective Structure of Dense Rocky Planet Atmospheres. We use a one-dimensional line-by-line radiative–convective model to simulate hot, dense terrestrial-planet atmospheres. We find that strong shortwave absorption by H2O and CO2 inhibits near-surface convection, reducing surface temperatures by up to ∼2000 K compared to fully convective predictions. Pure-CO2 atmospheres are typically 1000 K cooler than pure H2O, with only a few percent of H2O required to elevate surface temperatures by hundreds of kelvins for a fixed incident stellar radiation. We also show that minor greenhouse gases such as SO2 and NH3 have a limited warming effect when H2O is abundant. We find that even for insolation values as high as 12,500 W m‑2 (37 × Earth's) planets with mixed CO2–H2O envelopes have surface temperatures in the 1200–2000 K range, limiting surface melting. Our results highlight the critical role of shortwave heating on magma ocean planets and the need for improved high-temperature spectroscopy beyond 20,000 cm‑1.

Keywords: Exoplanet atmospheric composition , Atmospheric evolution, Planetary atmospheres, Astrobiology, Exoplanet surface characteristics, Planetary science, Atmospheric composition, Habitable planets, Exoplanet atmospheres, Exoplanet atmospheric structure
Producing Dust through Simulated Glacial Abrasion of Basalt Clasts with Implications for Mars. Multiple processes have been proposed for the genesis of dust on Mars, including volcanic eruptions, eolian abrasion, bolide impacts, and glacial grinding. Atmospheric dust has a significant impact on climate that is heavily dependent on the particle size distribution (PSD) of the dust. Therefore, we ask, do different dust-generating mechanisms produce different dust PSDs and, consequently, different impacts on the climate? Glacial grinding is the erosive process of clasts embedded in the base of a glacier sliding across bedrock or subglacial sediment. We use basalt clasts as analogs to assess sediment production via experimental glacial grinding. We cut small (3 cm), flat- and point-tipped fabricated clasts from five distinct basalts and used a novel experimental apparatus to abrade them across a basal rock slab representing bedrock. Pointed clasts generally produced more sediment than flat clasts, as did clasts with vesicular textures compared to those with nonvesicular textures. The resulting PSDs show that most dust samples exhibit a primary mode, between 20 and 50 μm. These results indicate a tendency toward silt production from rock-on-rock grinding of basalt, akin to the conditions at the base of a wet-based glacier. Results were compared to sediment PSDs from other potential dust-producing mechanisms. Simulated glacial grinding of basalt generates proportionally ∼50% more fine dust (&lt;2.5 μm) than simulated eolian abrasion of basalt sand. Results from these experiments suggest that if widespread wet-based glaciation existed on Mars, the dust produced would have influenced the climate, although the net radiative effect is unknown.

Keywords: Planetary surfaces, Surface processes, Dust formation, Glaciers, Glaciation
JWST Reveals Spectral Tracers of Recent Surface Modification on Europa. Europa has been modified by a variety of geologic processes, exposing internally derived materials that are heavily irradiated by charged particles trapped in Jupiter's magnetosphere. Prior spectral analysis of H2O ice on Europa relied on low signal-to-noise data at wavelengths &gt;2.5 μm, limiting assessment of a 3.1 μm Fresnel peak that is diagnostic of exposed crystalline ice. We report new measurements of H2O ice spectral features using high signal-to-noise data collected by the NIRSpec spectrograph (1.48–5.35 μm) on the James Webb Space Telescope. These data reveal a narrow 3.1 μm crystalline H2O ice Fresnel peak, which is primarily located at southern latitudes in Tara and Powys Regiones. Our analysis indicates that crystalline ice exposed in these low-latitude regiones is likely sustained by ongoing thermal (re)crystallization outpacing charged particle amorphization of the top ∼10 μm of Europa's regolith over short timescales (&lt;15 days). We also measured H2O ice features centered near 1.5, 1.65, and 2.0 μm, and a broad 3.6 μm H2O continuum peak, which are all stronger at northern latitudes, in contrast to the 3.1 μm Fresnel peak identified at southern latitudes. These results support the hypothesis that H2O ice in Europa's regolith is vertically stratified, with amorphous ice grains dominating its exposed surface, except in Tara and Powys Regiones. We also find that a previously detected 4.38 μm 13CO2 feature is present almost exclusively at southern latitudes in Tara and Powys Regiones, likely derived from an internal source of carbon-bearing material.

Keywords: Surface processes, Surface composition, Europa, James Webb Space Telescope, Galilean satellites
Statistical Geochemical Constraints on Present-day Water Outgassing as a Source of Secondary Atmospheres on the TRAPPIST-1 Exoplanets. The TRAPPIST-1 planetary system is observationally favorable for studying if planets orbiting M stars can retain atmospheres and host habitable conditions. Recent JWST secondary eclipse observations of TRAPPIST-1 c rule out a thick CO2 atmosphere but do not rule out atmospheric water vapor or its photochemical product, oxygen. Given the high expected escape rate, maintenance of atmospheric water vapor would require a present-day water source, such as volcanic outgassing. Here, we simulate water outgassing on the TRAPPIST-1 planets over a broad phase space that is based on solar system terrestrial bodies. We then apply two filters based on observation and geochemistry that narrow this phase space and constrain the plausible outgassing scenarios. For all seven TRAPPIST-1 planets, we find that the water outgassing rate is most likely ∼0.03x Earth's but has upper limits of ∼8x Earth's. The allowed range also implies low, Mars-like magma emplacement rates and relatively dry, Earth-like mantles, although mantle water mass fractions up to 1 wt% are possible. We also present scenarios with magma emplacement rates similar to Mars, Earth, and Io, resulting in different preferred mantle water content and outgassing rates. We find that water outgassing rates are potentially high enough to balance water escape rates, providing a theoretical pathway for the TRAPPIST-1 planets to maintain surface water or water-vapor-containing atmospheres over long timescales. The bounds on outgassing rates and interior properties can be used in atmospheric chemistry and escape models to contextualize future observations of the TRAPPIST-1 planets, and may be applicable to other terrestrial exoplanets.

Keywords: Planetary system evolution, Water vapor, Exoplanets, Mars, Planetary atmospheres, Earth (planet), Solar system evolution, Planetary geology, Io, Planetary interior, Exoplanet atmospheres, Volcanism
Gravity Imaging Radio Observer (GIRO) for Planetary Science and Mission Opportunities. The Gravity Imaging Radio Observer (GIRO) is a concept for a high-performance, battery-powered radio probe designed to be released in the proximity of a target planetary body to study its gravitational variations. Using the host spacecraft's communications system, the GIRO probes would receive and transmit a coherent carrier signal back to a host spacecraft, providing high-precision range-rate data with accuracy ≤1 μm s‑1 at a 60 s count time, which is 10–100 times better than the performance of conventional ground-based radiometric data. GIRO is spin stabilized, which significantly reduces nongravitational perturbations, making it ideal for acquiring clean gravitational signals for exploring planetary interiors. Additionally, the use of a specifically designed, carrier-only, analog transponder makes GIRO low cost. Furthermore, a host spacecraft could release multiple GIROs, reducing risk when exploring hazardous environments. In this paper, we describe the GIRO probe and deployer design concept and present scenarios where GIRO enables gravity measurements that would be challenging to achieve with conventional approaches.

Keywords: Space probes, Planetary probes
Classifying and Characterizing the Evolution of the Minimum Orbit Intersection Distance for Near-Earth Asteroids. In this paper, the minimum orbit intersection distances (MOIDs) of near-Earth asteroids (NEAs) over the next 200 yr are computed and analyzed in detail. It is shown that the MOID of an NEA relative to the Earth–Moon barycenter is usually a better metric for predicting a potential impact than that relative to the Earth. Subsequently, a novel MOID evolution index (MEI) spanning from 0.0 to 9.9 is proposed, and the orbits of NEAs are classified into 100 distinct categories by considering the variations of the MOID over time, which is useful for quickly screening and prioritizing hazardous asteroids for future research. Furthermore, it is demonstrated that a linear fitting to the MOID evolution provides a simple yet valid approach for most of the NEAs, which is useful for quickly estimating the MOID value without the need to perform an orbit propagation. As a result, a scheme with several parameters is proposed to characterize the MOID variations as well as the relative position information of the critical points along the orbits associated with the minimum distances. A database incorporating these parameters and the MEI values is therefore established for the cataloged NEAs, enabling the derivation of statistically constrained upper bounds for the secular MOID drift rate as a function of the semimajor axes. Finally, some special orbital configurations and dynamical mechanisms that may lead to a large deviation from the linear fit or multiple orbit crossings are also investigated, indicating the intricate nature in the patterns of MOID evolution for some NEAs.

Keywords: Near-Earth objects, Close encounters, Asteroid dynamics
The Effect of the Io Plasma Torus on Precise Orbit Determination and Gravity Recovery: Application to Europa Clipper. The neutral gases released by the intense volcanic activity of the Jupiter moon Io, once ionized by the Jupiter magnetic environment, give rise to a toroidal plasma distribution known as the Io plasma torus (IPT). Radio signals passing through charged-particle environments such as the IPT are heavily perturbed proportionally to the rate of change of the charged-particle distribution along the path of the radio wave. If not properly calibrated, the IPT may induce significant perturbation on the radiometric tracking link to Earth. The radio tracking signal is the main observable for the Gravity and Radio Science (G/RS) investigation on NASA's Europa Clipper, whose aim is to measure the gravity field, tidal response, and moment of inertia of Europa, and to precisely reconstruct the trajectory of the probe in support of other scientific investigations. In this work, we quantify the detrimental effects of the IPT on the radiometric observables. We show how these affect the products of the G/RS, and prove the necessity of accurate calibrations. We simulate different calibration strategies to mitigate its net perturbative effect, based on currently available models of the IPT. Considering that these models have been developed with Juno in mind, they are tailored to its orbital geometry and we show that they cannot be easily applied to other geometries. We conclude that, although the model-based calibration strategies can be very effective, further work will be needed to make them applicable to probes with a significantly different orbital geometry such as Europa Clipper or ESA's JUICE.

Keywords: Space plasmas, Europa, Calibration, Gravity anomaly, Planetary science, Orbit determination
An Assessment of Organics Detection and Characterization on the Surface of Europa with Infrared Spectroscopy. Organics, if they do exist on Europa, may only be present in trace amounts on the surface. NASA's upcoming mission Europa Clipper is going to provide global, high-quality data of the surface of Europa in the near-infrared (NIR), specifically the 3–5 μm region, where organics are rich in spectroscopic features. In this work we investigate Europa Clipper's ability to constrain the abundance of selected trace species of interest that span different chemical bonds found in organics, such as C–H, C=C, C≡C, C=O, and C≡N, via NIR spectroscopy in the 3–5 μm wavelength region. We simulate reflectance spectra of these trace species mixed with water ice, at varying signal-to-noise ratio and abundance fractions. The evidence for the trace species in a mixture is evaluated using two approaches: (1) calculating average strength of absorption feature(s), and (2) Bayesian model comparison (BMC) analysis. Our simulations show that sharp and strong spectroscopic features of trace (∼5% abundance by number) organic species should be detectable at &gt;3σ significance in Europa Clipper–quality data. A BMC analysis pushes the 3σ detection threshold of trace species even lower to &lt;1% abundance. We also consider an example with all trace species mixed together, with overlapping features, and BMC is able to retrieve strong evidence for all of them and also provide constraints on their abundance. These results are promising for Europa Clipper's capability to detect trace organic species, which would allow correlations to be drawn between the composition and geological regions with possibly endogenic material.

Keywords: Bayesian statistics, Infrared spectroscopy, Surface composition, Europa, Remote sensing, Planetary science
Photoionization and Photodissociation Rates across a Solar Cycle. Unattenuated photoionization and photodissociation rate coefficients are calculated using solar spectral irradiance measurements across a continuous solar cycle spanning 2004–2014. These rates are organized by corresponding daily F10.7P indices, where F10.7P  =12(F10.7+F10.7A) , F10.7 is a common historical proxy for solar ultraviolet and soft X-ray activity, and F10.7A is its 81 day running average. Power-law relationships are established between F10.7P and photo rate coefficients for 48 reactions across 12 of the most common species in solar system upper atmospheres and cometary comae: H, H2, OH, H2O, O, O2, C, CO, CO2, N2, N, and CH4. The resulting coefficients are broadly consistent with previous estimates and provide a practical, efficient means of estimating photoionization and photodissociation rates for a range of planetary and cometary applications.

Keywords: Photoionization, Upper atmosphere, Comae, Photodissociation reactions, Planetary atmospheres, Solar spectral irradiance
Temperature, Albedo, and Emissivity of Triton and Proteus from Voyager 2 IRIS Data. The Voyager 2 infrared interferometer and spectrometer (IRIS) spectra for Triton are revisited, and the Proteus IRIS spectra are looked at for the first time. Fifty more spectra are added to the average of 16 previously used for Triton. The unit emissivity Planck function temperature result is 37.9 ± 0.5 K. Iterating IRIS temperatures over several emissivities allows for constraints on emissivity and Bond albedo based on past data. Upper and lower bounds on Triton's temperature and albedo of 37.9 ± 0.5 to 46.1 ± 0.7 K for temperature and 0.67‑0.86 for albedo are determined from the IRIS data and previous albedo results. For Proteus, the surface temperature is found to be 47.4 ± 0.7 K, along with an emissivity from ∼0.75 to 1 and Bond albedo between 0.2 and 0.3.

Keywords: Neptunian satellites, Far infrared interferometry, Small Solar System bodies, Triton