Sazuna/UAT_keywords huggingface dataset:
Determinations of Asteroid Masses Using Mutual Encounters Observed in the Legacy Survey of Space and Time. Using published simulations of the 10 yr Legacy Survey of Space and Time (LSST), we forecast its ability to determine the masses of individual main-belt asteroids (MBAs) through precise astrometry of any pairs of the ≈1.2 million known MBAs undergoing close gravitational encounters during the survey. The uncertainty σI on the impulse applied to a tracer asteroid by its deflector is derived from the Fisher matrix of the tracer's astrometric data, including an azimuthal acceleration from the Yarkovsky effect as a free parameter for each tracer. If only LSST observations are available, the mean forecasted σI is 7 × 10‑6 m s‑1 for MBAs at apparent magnitude mV &lt; 19.5, degrading ≈10× for mV = 23. The forecasted median uncertainty on the mass of a deflector MBA is ≈3 × 10‑14M⊙, with a wide range of variation depending on the (random) configurations of the closest encounters. All of these figures improve ≈ fivefold if strong pre-LSST astrometry is available. Use of LSST data will increase the number of MBAs with masses measured to 20% accuracy or better from the present ≈70 to between 200 and 550, depending on quality of pre-LSST data, if all MBAs have mass-to-reflected-light ratios (M/Ls) at the low end of the currently measured bodies. If high-end M/Ls are more common, 580–1100 bodies will attain a signal-to-noise ratio &gt; 5, including nearly all bodies with absolute magnitude H &lt; 10 and some as faint as H = 13. We forecast that ≈20 new Jupiter Trojans could also have masses measured at &lt;20% accuracy. Tables of the measurable deflector MBAs and their tracers are provided.

Keywords: Main belt asteroids, Ephemerides
A Systematic Study of Hot O Production and Escape from Martian Atmosphere in Response to Enhanced Extreme-ultraviolet Irradiance from Solar Flares. The study of the evolution of Martian atmosphere and its response to EUV irradiation is an extremely important topic in planetary science. One of the dominant effects of atmospheric losses is the photochemical escape of atomic oxygen from Mars. Increasing the magnitude of the irradiation changes the response of the atmosphere. The purpose of the current paper is to analyze the effects of enhanced EUV irradiation on the escape rates of oxygen atoms. We have used the solar flare of 2017 September 10 as the baseline flare intensity and varied the intensity of the flare from a factor of 3 up to 10 times the baseline flare. We see an increase in the escape flux by ∼40% for flares up to 5× the intensity of the baseline flare. However, beyond this point, the increase in escape flux tapers off, reaching only about 17% above the baseline. At 10× the baseline flare intensity, the escape flux decreases by nearly 25% compared to the original flare's escape rate. We also found that the total escape amount of hot O peaks at 7× the original flare intensity. Additionally, we have studied the effects of the timescales over which the flare energy is delivered. We find that energy dissipative processes like radiative cooling and thermal collisions do not come into play instantaneously. The escape flux from higher-intensity flares dominates initially, but as time progresses, energy dissipative processes have a significant effect on the escape rate.

Keywords: Mars, Solar flares
Diffusion-adsorption of Water Vapor in Chemically Activated Lunar Soil. Silicate grains on the lunar surface have a wide range of desorption energies due to activated surface sites that persist in the extreme vacuum of space. Two endmember models of adsorption are constructed that represent opposite extremes for the mobility of adsorbed H2O on the grain surface. Then, governing equations for diffusion are derived that take the range of desorption energies and the microroughness of the grains into account, two surface heterogeneities important on the lunar surface. One application of these equations is the prediction of the adsorbate profile above buried ice. Another application is the adsorbate profile when water is sourced from exospheric infall. In this case, adsorbate concentrations increase with depth as the temperature amplitude decays.

Keywords: Water vapor, Lunar regolith, The Moon, Astrochemistry, Lunar surface
A Terminology and Quantitative Framework for Assessing the Habitability of Solar System and Extraterrestrial Worlds. The search for extraterrestrial life in the solar system and beyond is a key science driver in astrobiology, planetary science, and astrophysics. A critical step is the identification and characterization of potential habitats, both to guide the search and to interpret its results. However, a well-accepted, self-consistent, flexible, and quantitative terminology and method of assessment of habitability are lacking. Our paper fills this gap based on a 3 yr long study by the NExSS Quantitative Habitability Science Working Group. We review past studies of habitability but find that the lack of a universally valid definition of life prohibits a universally applicable definition of habitability. A more nuanced approach is needed. We introduce a quantitative habitability assessment framework that enables self-consistent, probabilistic assessment of the compatibility of two models: first, a habitat model, which describes the probability distributions of key conditions in the habitat, and second, a viability model, which describes the probability that a metabolism is viable given a set of environmental conditions. We provide an open-source implementation of this framework and four examples as a proof of concept: (a) comparison of two exoplanets for observational target prioritization, (b) interpretation of atmospheric O2 detection in two exoplanets, (c) subsurface habitability of Mars, and (d) ocean habitability in Europa. These examples demonstrate that our framework can self-consistently inform astrobiology research over a broad range of questions. The proposed framework is modular so that future work can expand the range and complexity of models available, both for habitats and for metabolisms.

Keywords: Mars, Europa, Astrobiology, Xenobiology, Biosignatures, Habitable zone, Habitable planets, Exoplanet atmospheres
Multi-criteria Overlay Analysis for Identifying Preferred Exploration Zones on Mars. Selecting sites for future human and robotic missions to Mars requires the integration of diverse data sets. A variety of global data sets have been exploited, including geological, mineralogical, and topographical. This study utilizes a Geographic Information System based Multi-Criteria Overlay Analysis technique to identify optimal exploration zones on Mars. A set of criteria were built according to both scientific objectives and engineering constraints proposed by the Mars Exploration Program Analysis Group. The resulting composite maps highlight regions that meet both scientific and in situ resource utilization criteria, as well as engineering constraints. The proposed regions are within midlatitudes, are at low elevation, and display moderate to high thermal inertia. Further examination of the map generated using different methods has enabled us to refine these selections based on the availability of resources like water ice and the previously proposed landing sites. A total of 23 regions identified held the highest statistical score, which we suggest merits further in-depth analysis. This technique allows for a flexible and scalable methodology that can be adapted as new data sets become available, thus continuously offering refined site recommendations.

Keywords: Mars, Remote sensing
Laser-based Mass Spectrometry for the Identification of Potential Biomarkers and Habitability Indicators on Polygon Structures. Polygonal structures, some of which are formed in salt deposits, have been documented at numerous locations on the surface of Mars, clearly visible from orbit with high-resolution imaging systems and spectral techniques. Based on a terrestrial analog, these deposits are potential locations to harbor biomarkers, which play a key role in the search for extraterrestrial life. This study examines the measurement capabilities of a laser-based mass spectrometer for the chemical composition analysis of such polygonal structures found in the Boulby Mine, United Kingdom, a Mars analog site. A space-prototype laser ablation ionization mass spectrometry system was used to measure the elemental composition of the material. The analysis for potentially habitable conditions and the presence of preserved biomarkers is based on the abundance of the CHNOPS elements in the halite host. In total, six samples, three from the edge and interior, respectively, of various polygons were investigated. The chemical analysis showed that the edges of polygonal structured salt deposits are preferential sites for element accumulation, with a higher abundance in CHNOPS elements and other trace elements necessary for the formation and maintenance of life. Polygonal structures might be alternative landing sites for future in situ space exploration missions devoted to life detection. The availability and ability to interpret imaging data from orbit enable an easy targeting of polygon structures, thus improving the selection for a landing site with higher potential to detect biosignatures and reducing mission costs by deploying dedicated instrumentation for in situ analysis.

Keywords: Mass spectrometers, Time-of-flight mass spectrometry, Experimental techniques, Spectrometers, Biosignatures, Laser ablation
Thermal-IR Observations of (152830) Dinkinesh during the Lucy Mission Flyby. NASA's Lucy spacecraft flew by the main-belt asteroid (152830) Dinkinesh on 2023 November 1, providing a test of its instruments and systems prior to its encounters with the Jupiter Trojans and enabling an opportunity for scientific investigation of this asteroid. Analysis of disk-integrated radiance spectra of Dinkinesh collected by the Lucy Thermal Emission Spectrometer (L'TES) instrument during the close approach reveals a thermal inertia for Dinkinesh of 91 ± 24 J m‑2 K‑1 s‑1/2 and a surface roughness of 35° ± 7° rms slope. These values for the thermal inertia and surface roughness are comparable to values derived for other small S-type asteroids such as (65803) Didymos. The Dinkinesh flyby also provided the opportunity to develop new techniques for extracting data when the target body does not fill the field of view of the L'TES instrument, which proved challenging for predecessors of this instrument such as OTES on OSIRIS-REx. The grain size of the regolith of Dinkinesh, estimated to be  r=1.2‑0.6+0.9  mm, is below expected trends with size but is comparable to that of similarly sized asteroids that are either binaries or may have undergone rotational fission in the past. These findings imply that fine-grained materials are being preferentially retained on the primaries of multiple systems, either by cohesive forces or by redeposition after impact events on the secondaries.

Keywords: Main belt asteroids, Asteroids, Infrared spectroscopy, Flyby missions
Investigating the Geotechnical Properties of the Lunar South Pole with NASA VIPER's Mobility System. The NASA Volatiles Investigating Polar Exploration Rover (VIPER) is capable of assessing the geotechnical properties of the lunar south pole's terrain, specifically as they pertain to terramechanics or the wheel–terrain interaction, combining the rover's mobility system and science payloads. This paper focuses on one key aspect of VIPER's mission: the quantitative evaluation of geotechnical parameters via tractive performance by analyzing wheel and wheel–regolith interaction dynamics. As VIPER navigates the largely uncharted terrain of the Moon's south pole, sophisticated onboard instrumentation will monitor and record detailed interactions between the rover's wheels, chassis, and the lunar surface. These measurements will capture critical data such as wheel slip and sinkage, offering insights into the mechanical behavior of the soil under actual lunar conditions. The findings from VIPER are expected to provide a foundational understanding of the lunar south pole's regolith mechanics, directly informing the design and navigation strategies of future lunar missions, including the deployment of more advanced rovers and crewed vehicles. By integrating lunar surface observations with the rover's kinematic model and understood terrestrial mobility performance, the study aims to enhance predictive accuracy regarding rover tractive performance over sloped, level, and potentially volatile-rich terrain. Ground truth geotechnical assessments and proceeding mobility characterization work will serve as a cornerstone for verifying and improving both terrestrial test approaches and simulation models that underpin mission planning and risk management for subsequent explorations.

Keywords: Lunar surface, Lunar regolith
Laboratory Investigation of CO<SUB>2</SUB>-driven Enhancement of Radiolytic H<SUB>2</SUB>O<SUB>2</SUB> on Europa and Other Icy Moons. Observations of Europa's leading hemisphere reveal elevated H2O2 in the warmer, low-latitude chaos terrains compared to the colder, polar regions. This distribution disagrees with prior laboratory radiolysis studies of pure water ice, which show higher H2O2 yields at colder temperatures. The regions with higher peroxide abundance, Tara and Powys Regiones, also present increased amounts of CO2, possibly sourced from Europa's interior. To investigate whether CO2 influences radiolysis of water ice to boost H2O2 production, we irradiated water ice doped with varying amounts of CO2 with 10 keV electrons at 70 and 100 K. Our results indicate that CO2, even in trace amounts (&lt;3%), significantly enhances H2O2 yields at temperatures relevant to Europa. We discuss the mechanisms by which CO2 boosts peroxide synthesis and quantify H2O2 creation and destruction cross sections and G-values across different CO2 concentrations. These findings provide a plausible explanation for the perplexing H2O2 distribution on Europa and has implications for understanding peroxide on other icy bodies such as Ganymede and Charon, where it has been detected alongside CO2.

Keywords: Plutonian satellites, Experimental data, Surface composition, Laboratory astrophysics, Carbon dioxide, Radiation interactions (Ice), Europa, Galilean satellites
Particle Accretion in Microgravity. I. Particle Sizes and Bulk Densities. The precise mechanisms related to the accretion of protoplanetesimals from dust in protoplanetary disks (PPDs) are poorly understood. In order to better understand the early stages of planet formation and the growth of millimeter–centimeter agglomerates, we conducted a series of aggregation experiments in reduced gravity. Our objectives are to determine the effects of particle size, bulk density, and composition on the aggregation potential of dust-scale grains. This work builds upon previous microgravity experiments initially performed by astronaut Don Pettit on board the International Space Station, where free-floated bags of finely grained materials showed the aggregation of the cohesive materials. We expand upon these experiments using material more analogous to the PPD such as olivine, enstatite, ordinary chondrite, carbonaceous chondrite, and a carbonaceous chondrite simulant. We find that particle size is the most important driver of aggregate growth, with bulk density showing little dependence. The largest aggregate size ratios were formed from the finest particle size distributions, while aggregate sizes approach the mean grain size for particles greater than 1 mm. We measured aggregate sizes spanning roughly 2 orders of magnitude (∼0.2–20.0 mm), but the results show 5 orders of magnitude variations in aggregate size ratios (∼1–1 × 105). This could suggest that protoplanetesimals have an increased likelihood of accreting from micron-sized grains in particle size distributions with initially steeper slopes. Our results further the body of work that points to grain size and grain properties constraining the growth potential of protoplanetesimals, with implications for the timescale and initial conditions of accretion in the disk.

Keywords: Accretion, Microgravity, Planet formation, Planetesimals
Dust Production Rates in Jupiter-family Comets. II. Trends and Population Insights from ATLAS Photometry of 116 JFCs. Jupiter-family comets (JFCs) have orbital periods of less than 20 yr and therefore undergo more frequent sublimation compared to other comet populations. The JFCs therefore represent the ideal dynamical population for investigating the dust production rates at high cadence. We analyzed observations by the Asteroid Terrestrial-impact Last Alert System (ATLAS) of 74 JFCs that reached perihelion in 2022 and 2023. The work contained in this study builds on our previous work, for a total of 116 JFCs over a 4 yr period. Using the Afρ parameter, we measured the dust production rates of each JFC as a function of heliocentric distance. We found that there remained a clear preference for JFCs to reach their maximum A(0°)fρ post-perihelion, with 170P/Christensen, 254P/McNaught, and P/2020 WJ5 (Lemmon) reaching a maximum A(0°)fρ between 200 and 400 days after perihelion. However, all JFCs reached their maximum dust production within 10% of their orbital period relative to perihelion. Fitting A(0°)fρ as a function of  (Rh)n , we measured statistically significant differences in the distribution of pre-perihelion and post-perihelion activity index n, with average activity indices of ‑5.2 ± 4.5 and ‑3.2 ± 2.7, respectively. We derived upper limits for the nuclear radii of comets 444P/WISE-PANSTARRS and 459P/Catalina as Rn ≤ 1.5 ± 0.2 km and Rn ≤ 1.7 ± 0.1 km, respectively. We measured six outbursts in comets 97P/Metcalf-Brewington, 99P/Kowal 1, 118P/Shoemaker-Levy 4, 285P/LINEAR, and 382P/Larson. From our 4 yr of observing JFC outbursts in the ATLAS data, the average increase in magnitude was ‑1.3 ± 0.8.

Keywords: Wide-field telescopes, Short period comets, Solar system, Time domain astronomy, Broad band photometry, Comets, Coma dust
Simulating Science Operations for a Joint Rover-helicopter Mission Architecture in a Mars Analog Setting. Aerial platforms can explore planetary surfaces without the mobility limitations of rovers and landers. Inspired by the recent successes and challenges of NASA's IngenuAity Mars Helicopter, the Rover-Aerial Vehicle Exploration Network project explored the operations and science value of a dual-platform rover-helicopter mission architecture coupled with simulated orbiter image data. A remote mission operations team carried out a 5 day long Mars mission simulation executed by a field team in the Rainbow Basin Natural Area near Barstow, California, USA. The simulation demonstrated the rover's ability to collect progressively finer-scale, specifically targeted image and compositional observations with a complementary multi-instrument payload. The helicopter excelled at the collection of extensive image surveys, providing views of diverse terrains and geologic units within the exploration area otherwise inaccessible to the rover. Of the helicopter data, high-resolution, low-altitude oblique images proved to be the most useful from a science and strategic operational planning perspective. The dual-platform mission architecture had clear science advantages over the individual rover or helicopter investigations during the simulation, but sharing daily data downlink between the mission platforms presented one of the greatest operational challenges. Rover operations demanded daily "reactive" tactical planning and rapid downlink of science data to enable targeting and traverse decisions, while the helicopter was best suited to a "predictive" advanced planning timeline for operations, data volume management, and science analysis.

Keywords: Geological processes, Mars, Planetary science, Planetary geology
Orbital Capture of Ejecta into Periodic Orbits around Binary Asteroid (65803) Didymos. The successful impact of the Double Asteroid Redirection Test (DART) spacecraft on Dimorphos enabled the first-ever extensive observation of a postimpact ejecta tail from a binary asteroid system. Studying the ejecta can provide insights into impact physics and asteroid composition and inform future asteroid missions. In this research, the orbital capture of the impact ejecta around the Didymos binary asteroid system is investigated. The ejecta dynamics are described using an augmented bicircular restricted four-body model, which incorporates the binary's irregular gravity field and solar radiation pressure (SRP) acceleration. Typical periodic orbit (PO) families, including planar Lyapunov and terminator orbits, are selected as the candidates for capture analysis. The candidate POs are perturbed and backward-propagated using the invariant manifold theory, and eligible trajectories intersecting the asteroids' surfaces are recorded. The ejecta characteristics of different POs are summarized from three principal aspects: ejection location, ejection velocity, and ejection angle. The influence of two critical factors is qualitatively assessed, including the geometry of the asteroids in the binary system and the strength of SRP acceleration. Lastly, the likelihood for the ejecta from the DART impact being transferred to candidate POs is assessed.

Keywords: Ejecta, Asteroids, Asteroid dynamics, Astronomical simulations
Freeze Concentration, Supercooling, and Glass Formation in Perchlorate and Chlorate Brines: Habitability in Salty Martian Ice. Oxychlorine salts, including chlorates and perchlorates, are widespread in Martian soil. Despite this significance, key metrics influencing the rheological properties and habitability of aqueous oxychlorine systems, such as the glass transition temperature (Tg), degree of supercooling, critical concentrations, and maximum freeze concentrations, remain poorly characterized. This study employs differential scanning calorimetry to measure the properties of supercooled aqueous solutions of Ca, Mg, and Na chlorate brines. We systematically quantify the effects of initial brine composition, concentration, and cooling or warming rates. Our results demonstrate that brines with concentrations exceeding the eutectic concentration readily supercool and vitrify at various cooling rates, whereas those below the eutectic concentration partially freeze. In these mixed-phase ice-brine systems, we quantify the fraction of water ice and glass phases formed from freeze concentration, along with the concentration of residual brine for both perchlorates and chlorates. Increased cooling rates favor supercooling and glass formation over ice formation, though the residual liquid concentration is minimally affected, indicating that initial solution concentration is the primary control factor. Even under equilibrium ice formation, the residual liquid phase can exhibit metastable behavior. The glass-forming ability is greatest for perchlorate anions and weakest for chloride anions, following the trend ClO4– &gt; ClO3– &gt; Cl–. Among cations, Mg2+ and Ca2+ show a greater propensity for glass formation compared to Na+. These findings enhance our understanding of liquid stability and metastability on Mars, supporting the potential for supercooled salty waters to persist as interconnected brine networks or nodes interspersed among ice grains.

Keywords: Ice composition, Mars, Ice physics, Planetary science, Thermal properties (Ice)