Sazuna/UAT_keywords huggingface dataset:
The MaNGA Dwarf Galaxy Sample (MaNDala): Stellar Profiles and Gradients Characterization. We derived robust radial profiles and inner/outer gradients of various stellar population (SP) properties for a sample of 124 bright dwarf galaxies, 107.53 ≤ M*/M⊙ ≤ 109.06, from the MaNDala sample, using integral field spectroscopy observations. Given the complex structure of dwarf galaxies, we explored four different methods to derive SP radial profiles: two based on concentric elliptical rings, and the other two exploiting the spatially resolved nature of the data. For each method, we applied four approaches to calculate the following inner (0 ≤ R/Re ≤ 1) and outer (0.75 ≤ R/Re ≤ 1.5) gradients: luminosity- and mass-weighted age and stellar metallicity, dust attenuation, Dn4000 index, stellar mass and star formation rate (SFR) surface densities, and specific SFR. While the point-spread function has a minor impact on the SP gradients, the choice of methodology for characterizing radial profiles significantly affects them. At fixed property, differences in inner gradients from concentric rings methods are typically ∼0.05–0.1 dex Re‑1, while outer gradients can reach 0.5–1 dex Re‑1, relative to the median of all gradients of that property,  med{∇G}i . Spatially resolved methods yield smaller differences, ≲0.1 dex Re‑1. For some SP gradients, such as ∇SFR, the dispersion among the methods is comparable to  med{∇G}i . While it is not possible to select a single preferred method for determining SP gradients, we suggest using  med{∇G}i  for each SP property. The resulting median age and metallicity suggest that, overall, bright dwarfs experienced moderate inside-out formation, accompanied by significant early SF from low-metallicity gas with outward radial migration of old SPs. The derived SP gradients provide strong constraints on feedback mechanisms in dwarf galaxies.

Keywords: Galaxy spectroscopy, Dwarf galaxies, Galaxy properties
AstroM<SUP>3</SUP>: A Self-supervised Multimodal Model for Astronomy. While machine-learned models are now routinely employed to facilitate astronomical inquiry, model inputs tend to be limited to a primary data source (namely images or time series) and, in the more advanced approaches, some metadata. Yet with the growing use of wide-field, multiplexed observational resources, individual sources of interest often have a broad range of observational modes available. Here we construct an astronomical multimodal dataset and propose AstroM3, a self-supervised pretraining approach that enables a model to learn from multiple modalities simultaneously. We extend the Contrastive Language-Image Pretraining (CLIP) model to a trimodal setting, allowing the integration of time-series photometry data, spectra, and astrophysical metadata. In a fine-tuning supervised setting, CLIP pretraining improves classification accuracy, particularly when labeled data is limited, with increases of up to 14.29% in spectra classification, 2.27% in metadata, and 10.20% in photometry. Furthermore, we show that combining photometry, spectra, and metadata improves classification accuracy over single-modality models. In addition to fine-tuned classification, we can use the trained model in other downstream tasks that are not explicitly contemplated during the construction of the self-supervised model. In particular we show the efficacy of using the learned embeddings to identify misclassifications, for similarity search, and for anomaly detection. One surprising highlight is the "rediscovery" of Mira subtypes and two rotational variable subclasses using manifold learning and dimensionality reduction algorithms. To our knowledge this is the first construction of an n &gt; 2 mode model in astronomy. Extensions to n &gt; 3 modes are naturally anticipated with this approach.

Keywords: Astrostatistics techniques, Variable stars
Interior and Climate Modeling of the Venus Zone Planet TOI-2285 b. As the discovery of exoplanets progresses at a rapid pace, the large number of known planets provides a pathway to assess the stellar and planetary properties that govern the climate evolution of terrestrial planets. Of particular interest are those planetary cases that straddle the radius boundary of being terrestrial or gaseous in nature, such as super-Earth and sub-Neptune exoplanets, respectively. The known exoplanet, TOI-2285 b, is one such case, since it lies at the radius boundary of super-Earth and sub-Neptune (Rp = 1.74 R⊕), and receives a relatively high instellation flux since its orbit exists within both the Habitable Zone and Venus Zone (VZ). Here, we present an analysis of the planetary interior and climate to determine possible evolutionary pathways for the planet. We provide volatile inventory estimates in terms of the planet's bulk density and interior composition. We performed climate simulations using ROCKE-3D that provide a suite of possible temperate scenarios for the planet for a range of topographical and initial surface water assumptions. Using the outputs of the climate simulations, we modeled JWST transmission and emission spectroscopy for each scenario. Our results demonstrate that there are temperate scenarios consistent with the known planetary properties, despite the planet's estimated steam atmosphere and its location relative to the VZ.

Keywords: Exoplanets, Venus, Planetary atmospheres, Exoplanet evolution, Exoplanet surfaces, Astrobiology, Planetary climates, Exoplanet structure, Habitable zone, Planetary interior, Habitable planets, Exoplanet atmospheres
Observation and Simulation of Mutual Approximations between Five Main Uranian Satellites. Mutual approximation is an emerging method for obtaining high-precision astrometric measurements of natural satellites and asteroids. We used the 80 cm YaoAn High Precision Telescope to observe mutual approximation events of the main Uranian satellites during the period from 2021 to 2023. The average of internal errors along the directions of apparent relative motion and position are 20.0 and 5.1 mas, respectively. On the other hand, the rms of differences between observational results and the Jet Propulsion Laboratory ephemeris along the direction of apparent relative motion and position are 42.5 and 20.6 mas, respectively. We also investigated the factors affecting astrometric precision and found two simple indicators to exclude the invalid mutual approximation events, i.e., the events that do not contribute to precision enhancement. One indicator is the impact parameters divided by the difference of two satellites' apparent semimajor axes; the other is the apparent relative velocity divided by the difference of their apparent orbital velocities. The resulting quotients of all invalid events are significantly larger than 1.1. Simulations confirm that the indicators are suitable for all the main Uranian satellites' mutual approximation events in recent years and the near future. Consequently, it is recommended to exclude invalid events from future observation campaigns by using the two indicators.

Keywords: Photographic astrometry, Uranian satellites
Adaptive Weighted Multi-image Shape from Shading for Precise Topographic Reconstruction at the Lunar South Pole. The generation and analysis of fine surface topography are critical for landing site selection at the lunar south pole. The Shape from Shading (SFS) technique can theoretically reconstruct a pixel-level resolution topographic model. However, traditional SFS methods fail to effectively balance fine-detail terrain reconstruction with mitigation of the effects of image noise. To address this issue, an improved multi-image SFS method with adaptive smoothness and brightness weighting (MI-AW-SFS) is developed for more reliable and pixel-wise 3D reconstruction, which utilizes multiple imagery and the corresponding low-resolution digital elevation model (DEM). The proposed method effectively restores fine details and accurate crater depths using an adaptive smoothness weight for each pixel based on the illumination direction gradient derived from image intensity and varying brightness weight that accounts for variations in image azimuth angles and original resolutions. Experiments were conducted using multiple Lunar Reconnaissance Orbiter Camera Narrow Angle Camera images of two potential landing areas located at the lunar south pole to validate the performance of the proposed method. Compared to the traditional single-image SFS and multi-image SFS methods, the MI-AW-SFS DEMs effectively capture intricate topographic details with reliable elevation, and comparisons with adjusted Lunar Orbiter Laser Altimeter laser points demonstrate that the MI-AW-SFS DEMs maintain overall topographic accuracy. The high-resolution surface slope and roughness maps generated from the MI-AW-SFS DEMs enable finer-scale topographic analysis. The experiment results indicate that the improved method can provide a robust solution for high-resolution lunar topographic reconstruction at the lunar south pole.

Keywords: Remote sensing
TESS Investigation—Demographics of Young Exoplanets (TI-DYE). III. An Inner Super-Earth in TOI 2076. Young (&lt;500 Myr) multiplanet transiting systems are valuable environments for understanding planet evolution by offering an opportunity to make direct comparisons between planets from the same formation conditions. TOI 2076 is known to harbor three 2.5–4 R⊕ planets on 10–35 days orbits. All three are JWST cycle 3 targets (for transmission spectroscopy). Here, we present the detection of TOI 2076 e; a smaller (1.35 R⊕) inner (3.02 days) planet in the system. We update the age of the system by analyzing the rotation periods, lithium equivalent widths, color–magnitude diagram, and variability of likely comoving stars, finding that TOI 2076 and comoving planetary system TOI 1807 are 210 ± 20 Myr. The discovery of TOI 2076 e is motivation to revisit known transiting systems in search of additional planets that are now detectable with new TESS data and updated search methods.

Keywords: Exoplanet evolution, Transit photometry, Young star clusters, Exoplanets
Determining the Methanol Deuteration in the Disk Around V883 Orionis with Laboratory Measured Spectroscopy. Deuterium fractionation, as studied through mono-deuterated methanol, is frequently used as a diagnostic tool to trace the physical conditions and chemical evolution of interstellar sources. This study investigates methanol deuteration in the disk around V883 Ori, utilising recent laboratory spectroscopic data for CH2DOH and CH3OD along with Atacama Large Millimeter/submillimeter Array observations. The derived column densities for CH2DOH and CH3OD are (5.14 ± 0.08) × 1016 cm‑2 and (4.22 ± 0.06) × 1016 cm‑2, respectively. The analysis demonstrates the influence of spectroscopic data on determining molecular column density, excitation temperature, and, most importantly, the inferred D/H ratio. The D/H ratio for CH2DOH is calculated to be (7.3 ± 1.5) × 10‑3 after applying a statistical correction, while the D/H ratio for CH3OD is (1.79 ± 0.36) × 10‑2. The discovery of an unexpectedly low CH2DOH/CH3OD ratio (1.22 ± 0.02) in V883 Ori, however, raises further questions about the synthesis and chemical processes involved in CH3OD formation. Overall, this study underscores the importance of accurate spectroscopic data for studies of isotopic fractionation and provides new insights into methanol deuteration chemistry in star-forming regions. Future research, combining updated spectroscopy and chemical modeling, will help further constrain these processes across different masses and evolutionary stages.

Keywords: Interstellar molecules, Interstellar abundances, Star formation
The True Stellar Obliquity of a Sub-Saturn Planet from the Tierras Observatory and the Keck Planet Finder. We measure the true obliquity of TOI-2364, a K dwarf with a sub-Saturn-mass (Mp = 0.18 MJ) transiting planet on the upper edge of the hot-Neptune desert. We used new Rossiter–McLaughlin observations gathered with the Keck Planet Finder to measure the sky-projected obliquity λ = 7° + 10°–11°. Combined with a stellar rotation period of 23.47 ± 0.29 days measured with photometry from the Tierras Observatory, this yields a stellar inclination of 90° ± 13° and a true obliquity ψ = 15 .° 6 + 7 .° 7–7 .° 3, indicating that the planet's orbit is well aligned with the rotation axis of its host star. The determination of ψ is important for investigating a potential bimodality in the orbits of short-period sub-Saturns around cool stars, which tend to be either aligned with or perpendicular to their host stars' spin axes.

Keywords: Starspots, Transits, Planetary alignment, Exoplanet systems, Exoplanet astronomy, Planet hosting stars, Stellar rotation, Infrared photometry
Photometric Analysis of Asteroids in the Phocaea Region. The Phocaea asteroid family, one of the large ancient families located in the inner main belt, may be the sources of near-Earth asteroids (NEAs) due to the nearby 3:1 mean motion resonance with Jupiter, the ν6 secular resonance, and the Yarkovsky and Yarkovsky–O'Keefe–Radzievskii–Paddack (YORP) effects. Thus, understanding the influence of the Yarkovsky and YORP effects on the Phocaea family is one of the keys to figuring out the source of NEAs. However, the physical properties of most of the Phocaea family members are unknown at present. We perform a photometric analysis for 44 asteroids in the Phocaea region using photometric data obtained by ground-based and space-based telescopes (i.e., the Transiting Exoplanet Survey Satellite and Gaia). Based on the derived physical properties, we find significant footprints of the Yarkovsky and YORP effects on the Phocaea family members. Selecting five asteroids nearby the inside boundary of the V shape in the absolute-magnitude semimajor-axis (H, a) space, we estimate their densities considering their migration in semimajor-axis arises from the Yarkovsky effect. The bulk density of (852) Wladilena (3.54 g cm‑3) suggests a link to the H chondrite meteorites. Incorporating the grain density of the H chondrites, we estimate the macroporosities of the asteroids (290) Bruna, (1164) Kobolda, and (587) Hypsipyle, respectively, as 41%, 47%, and 65%, implying rubble pile structures. Considering the H chondrites link to asteroid (25) Phocaea, we suggest the parent body of the Phocaea family has been composed of H chondrite like material and the Phocaea family may be one of the sources of H chondrite meteorites.

Keywords: Sky surveys, Chondrites, Asteroids, Photometry
Collision Probability Evaluation of LAMOST Robotic Fiber Positioners in the Design Phase. Multiobject spectroscopic telescopes are crucial for modern astronomy. Among them, the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), with thousands of robotic fiber positioners (RFPs), is the one with the highest spectra acquisition rates. To guarantee no blind area, RFPs' working spaces are overlapped to a certain extent, leading to collisions between RFPs and damage to RFPs. Even with algorithms designed for collision avoidance, collisions still occur during operation. Despite a 99.6% success rate of the current adopted path-planning algorithm, 4% of RFPs fail to reach targets. Fail reasons, such as collisions, cause ongoing negative effects across multiple observation rounds, necessitating the replacement of many RFPs. LAMOST is upgrading its fiber positioning system. Considering the above-mentioned problem in the design phase is necessary. To address this challenge, we propose a mathematical model to assess the collision probability. Then, the proposed model is validated by Monte Carlo simulations. During collision probability calculation, we consider factors such as RFP structure, target allocation, motion requirements, and mechanical errors into consideration. Based on this, we employ the genetic algorithm to optimize RFP arrangements with the lowest collision probability and show its function in the design phase. The proposed method is designed for LAMOST, but it is suitable for the future design of newly proposed spectroscopic telescopes with RFPs.

Keywords: Automated telescopes, Astronomical instrumentation
Probing Abundance Variations Among Multiple Stellar Populations in the Metal-poor Globular Cluster NGC 2298 Using Gemini-South/GHOST. Studying the abundances in metal-poor globular clusters is crucial for understanding the formation of the Galaxy and the nucleosynthesis processes in the early Universe. We observed 13 red-giant stars from the metal-poor globular cluster NGC 2298 using the newly commissioned GHOST spectrograph at Gemini South. We derived stellar parameters and abundances for 36 species across 32 elements, including 16 neutron-capture elements. We find that the stars exhibit chemical anomalies among the light elements, allowing us to classify them into first generation (eight stars) and second generation (five stars). We derive a mean cluster metallicity of [Fe/H] = −1.98 ± 0.10 with no significant variation among cluster members. Most α- and Fe-peak elements display low star-to-star abundance dispersion, with notable exceptions for Sc, Ni, and Zn for which the dispersions in Sc vary significantly between stars from different generations to 2σ levels. Similarly, among the neutron-capture elements, we observed considerable differences in dispersion for Sr and Eu among the first and second generation stars to 2σ levels. We also confirm an intrinsic scatter beyond observational uncertainties for several elements using a maximum likelihood approach among stars from different generations. Additionally, we note an increase in [Sr/Eu] and [Ba/Eu] with [Mg/Fe] in first-generation stars indicating correlations between the productions of light r process and Mg. We find the universal r-process pattern, but with larger dispersions in the main r process than the limited-r elements. These differences in abundance dispersion, among first- and second-generation stars in NGC 2298, suggest complex and inhomogeneous early chemical enrichment processes, driven by contributions from multiple nucleosynthetic events, including massive stars and rare r-process events. *Based on observations obtained at the international Gemini Observatory, a program of NSF NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the U.S. National Science Foundation on behalf of the Gemini Observatory partnership: the U.S. National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovaci ón (Argentina), Ministério da Ciência, Tecnologia, Inovações Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea).

Keywords: Globular star clusters, Stellar populations, Stellar abundances, Population II stars, Chemical abundances, Stellar nucleosynthesis, Chemically peculiar stars
Multiparameter Constraints on Empirical Infrasound Period-Yield Relations for Bolides and Implications for Planetary Defense. How effective are methods for estimating bolide energies from infrasound signal period-yield relationships? A single global period–energy relation can obscure significant variability introduced by parameters such as the atmospheric Doppler wind profile and the bolide's energy deposition profile as a function of altitude. Bolide speed, entry angle, burst altitude, and multiepisode fragmentation may all play a role in defining the detected period of the shockwave. By leveraging bolide light-curve data from the Center for Near Earth Object Studies, we re-examined the period–energy relation as a function of these parameters. Through a bootstrap approach, we show that various event subsets can deviate from widely cited period–energy models and we identify which specific conditions most strongly reshape the period–energy scaling. The results define both the fidelity and reliability of period–energy relations when no additional data beyond the infrasound record is available and improve the outcome when supporting data from bolide trajectories and light curves are included. Ultimately, these findings expand the scope of earlier models, providing a nuanced and robust framework for infrasound-only yield estimation under a range of bolide scenarios.

Keywords: Planetary science
Accelerating Long-period Exoplanet Discovery by Combining Deep Learning and Citizen Science. Automated planetary transit detection has become vital to identify and prioritize candidates for expert analysis and verification given the scale of modern telescopic surveys. Current methods for short-period exoplanet detection work effectively due to periodicity in the transit signals, but a robust approach for detecting single-transit events is lacking. However, volunteer-labeled transits collected by the Planet Hunters TESS (PHT) project now provide an unprecedented opportunity to investigate a data-driven approach to long-period exoplanet detection. In this work, we train a 1D convolutional neural network to classify planetary transits using PHT volunteer scores as training data. We find that this model recovers planet candidates (TESS objects of interest; TOIs) at a precision and recall rate exceeding those of volunteers, with a 20% improvement in the area under the precision-recall curve and 10% more TOIs identified in the top 500 predictions on average per sector. Importantly, the model also recovers almost all planet candidates found by volunteers but missed by current automated methods (PHT community TOIs). Finally we retrospectively utilise the model to simulate live deployment in PHT to reprioritize candidates for analysis. We also find that multiple promising planet candidates, originally missed by PHT, would have been found using our approach, showing promise for upcoming real-world deployment.

Keywords: Classification, Convolutional neural networks, Exoplanet astronomy, Exoplanet detection methods, Transit photometry
Effects of Transient Stellar Emissions on Planetary Climates of Tidally Locked Exo-Earths. Space weather events in exoplanetary environments sourced from transient host star emissions, including stellar flares, coronal mass ejections, and stellar proton events, can substantially influence a planet's habitability and atmospheric evolution history. These time-dependent events may also affect our ability to measure and interpret its properties by modulating reservoirs of key chemical compounds and changing the atmosphere's brightness temperature. The majority of previous work focusing on photochemical effects, ground-level UV dosages, and consequences on observed spectra. Here, using three-dimensional general circulation models with interactive photochemistry, we simulate the climate and chemical impacts of stellar energetic particle events and periodic enhancements of UV photons. We use statistical methods to examine their effects on synchronously rotating TRAPPIST-1e-like planets on a range of spatiotemporal scales. We find that abrupt thermospheric cooling is associated with radiative cooling of NO and CO2, and middle-to-lower atmospheric warming is associated with elevated infrared absorbers such as N2O and H2O. In certain regimes, in particular for climates around moderately active stars, atmospheric temperature changes are strongly affected by O3 variability. Cumulative effects are largely determined by the flare frequency and the instantaneous effects are dependent on the flare's spectral shape and energy. In addition to effects on planetary climate and atmospheric chemistry, we find that intense flares can energize the middle atmosphere, causing enhancements in wind velocities up to 40 m s‑1 in substellar nightsides between 30 and 50 km in altitude. Our results suggest that successive, more energetic eruptive events from younger stars may be a pivotal factor in determining the atmosphere dynamics of their planets.

Keywords: Exoplanet atmospheric variability, Planetary climates, Stellar flares, Exoplanet atmospheres