Sazuna/UAT_keywords huggingface dataset:
WOCS XCV: NGC 7789: The Evolution of Li, Stellar Rotation, and Extended Main-sequence Turnoff. Precision UBVRI photometry of NGC 7789 is combined with Gaia data to map reddening variations across the cluster face. Hydra spectra, Gaia astrometry, and isochrone fitting constrain the absolute reddening, apparent modulus, and age, respectively, to E(B ─ V) = 0.30 ± 0.02, (m − M) = 12.51 ± 0.06, and 1.46 ± 0.02 Gyr for [Fe/H] between −0.2 and solar; the spectroscopic [Fe/H] = −0.13 ± 0.068 (median absolute deviation) from 156 single-star members. Corrections for variable reddening reduce the scatter in the unevolved main sequence below the turnoff. A(Li) is derived for only single-star members from the G dwarf Li plateau to the tip of the red giant branch. Giants separate into two distinct groups: probable first-ascent giants with detectable Li that decline with evolution toward the red giant tip, and stars within the clump and the asymptotic giant branch, which only exhibit upper limits. The A(Li) structure from the turnoff to the unevolved main sequence, including the Li dip, and the presence of an extended color spread among the upper main-sequence stars, are attributed to the  vsini  distribution, indicating the wall of the Li dip as the true hot boundary of the Kraft break. Differences in the color─magnitude diagram topology of NGC 7789 and NGC 752 are explored and attributed to differences in the individual cluster  vsini  distributions. Prior indications that main-sequence stars more massive than the Li dip evolve redward across the Li wall, undergoing rotational spin-down and Li depletion like stars within the Li dip, are confirmed.

Keywords: Johnson photometry, Stellar abundances, Interstellar reddening, Open star clusters, Stellar rotation
KMT-2022-BLG-1818Lb,c: A Cold Super-Jupiter with a Saturn Sibling. We present the discovery and analysis of the sixth microlensing two-planet system, KMT-2022-BLG-1818Lb,c, detected by a follow-up program targeting high-magnification events. The second planet was identified from implausible physical parameters for the models with a single planet. Both planets are subject to the well-known "close/wide" degeneracy, although for the first planet, which has a super-Jovian mass ratio of q2 ≃ 5 × 10−3 in both solutions, the close topology, with a normalized separation of s ≃ 0.70, is clearly preferred by ∆χ2 = 26. However, contrary to all previous two-planet microlensing systems, the mass ratio for the second planet, q3, is substantially (factor of ∼10) different for the Close and Wide topologies of the first planet. While this degeneracy is resolved in the present case due to high-cadence follow-up observations, the appearance of this new degeneracy indicates the need for caution in the analysis of future two-planet systems. A Bayesian analysis suggests that the host is likely a K dwarf star in the Galactic disk. The first planet is probably a super-Jupiter on a Jupiter-like orbit, while the second planet is a Saturn-class planet on either a Mercury-like or Saturn-like orbit.

Keywords: Gravitational microlensing, Gravitational microlensing exoplanet detection, Triple lens microlensing
Dust Collisions in Protoplanetary Disks: Atomic Simulations of the Surface Free Energy. Coagulation of dust particles in protoplanetary disks is the first step on the journey to the formation of planets. The surface free energy (SFE) of the dust particles determines the effectiveness of particles sticking to each other after collision, as well as the critical collision velocity above which fragmentation will occur. Studies of SFE have focused on the simplest silicate, silica, usually at standard temperature and pressure. However, protoplanetary dust grains have a wide variety of mineralogical compositions and temperatures, and a low-pressure environment lacking in water vapor. We perform molecular dynamics simulations using a ReaxFF-type potential of the SFE of silica, albite, and anorthite at temperatures ranging from 30 to 700 K in a true vacuum. We find that the SFE drops by tens of percent with increasing temperature or shifting to more complex silicate compositions. More dramatically, we find that the values of the SFE in a vacuum are 2 orders of magnitude higher than those usually measured in terrestrial laboratories. Our results confirm previous work that suggests that hydroxylation by monolayers of water produces this reduction in SFE in experiments. The coagulation of dust grains thus appears to depend critically on the cleanliness of their surfaces, as well as their temperature and composition.

Keywords: Dust physics, Atomic physics, Surface processes, Protoplanetary disks, Planet formation
Searching for GEMS: TOI-5349 b is a Saturn-like Planet Orbiting a Metal-rich Early M Dwarf. We report the confirmation and analysis of TOI-5349 b, a transiting, warm, Saturn-like planet orbiting an early M dwarf with a period of ∼3.3 days, which we confirmed as part of the Searching for GEMS survey. TOI-5349 b was initially identified in photometry from NASA's Transiting Exoplanet Survey Satellite mission and subsequently confirmed using high-precision radial velocity (RV) measurements from the Habitable-zone Planet Finder and MAROON-X spectrographs, and from ground-based transit observations obtained using the 0.6 m telescope at Red Buttes Observatory and the 1.0 m telescope at the Table Mountain Facility of Pomona College. From a joint fit of the RV and photometric data, we determine the planet's mass and radius to be 0.40 ± 0.02 MJ ( 127.4−5.7+5.9M⊕ ) and 0.91 ± 0.02 RJ (10.2 ± 0.3 R⊕), respectively, resulting in a bulk density of ρp = 0.66 ± 0.06 g cm−3 (∼0.96 the density of Saturn). We determine that the host star is a metal-rich M1-type dwarf with a mass and radius of 0.61 ± 0.02 M⊙ and 0.58 ± 0.01 R⊙, and an effective temperature of Teff = 3751 ± 59 K. Our analysis highlights an emerging pattern, exemplified by TOI-5349, in which transiting Giant Exoplanets around M dwarf Stars (GEMS) often have Saturn-like masses and densities and orbit metal-rich stars. With the growing sample of GEMS planets, comparative studies of short-period gas giants orbiting M dwarfs and Sun-like stars are needed to investigate how metallicity and disk conditions shape the formation and properties of these planets.

Keywords: M dwarf stars, Radial velocity, Transits
A Radio-interferometric Imaging Method Based on Adaptively Learned Sparsifying Basis. In radio interferometry, the process of reconstructing the signal from measured visibilities is an ill-posed inverse problem. Although the compressive sensing (CS) technology has been successfully applied in radio interferometry, the conventional CS methods use a fixed set of sparse bases for the entire astronomical image, which cannot achieve a sufficiently high degree of sparsity and thus affects the performance of CS reconstruction. This paper proposes a novel radio-interferometric imaging algorithm based on adaptively learned sparsifying basis. Considering that many signals in the universe are nonstationary, the proposed method uses an adaptive learning dictionary to sparsely represent overlapped image patches, which can effectively capture local features of the image and reduce the artifacts. Furthermore, the split Bregman iteration algorithm is employed to alternately solve the dictionary learning and image estimation. The effectiveness of the proposed method is validated through multiple simulation experiments.

Keywords: Computational methods, Radio interferometry, Aperture synthesis, Radio telescopes
Benchmarking Differential Reddening in Front of Globular Clusters. Interstellar extinction is a major obstacle in determining accurate stellar parameters from photometry near the Galactic disk. It is especially true for globular clusters at low galactic latitudes, which suffer from significant amounts of spatially variable reddening. Although differential reddening maps are available for tens of clusters, establishing and validating the absolute zero-point of relative maps is a challenge. In this study, we present a new approach to determine and evaluate absolute reddening zero-points for Galactic globular clusters by combining 3D reddening maps with Gaia DR3 RR Lyrae data. As a first case study, we investigate the low-latitude globular cluster M9. We compare the Gaia photometry and color data of the cluster member RR Lyrae stars to field RR Lyrae stars with accurate parallaxes and whose photometric metallicities match that of M9, as well as to theoretical models. We calculate the dereddened Gaia colors for the M9 stars based on three zero points. We confirm that the original SFD map by D. J. Schlegel et al. (1998) appears to be overcorrecting the reddening for at least some RR Lyrae stars, albeit not excessively. In contrast, the 3D Bayestar map and the recalibrated version of the SFD map provide physically plausible reddenings, which we accept as lower and upper limits for M9, respectively. Our results provide a physically motivated reddening range for M9 and outline a methodology that can be directly extended to other globular clusters that are accessible to the Gaia mission, and to other multicolor sky surveys, such as the Rubin Observatory.

Keywords: Globular star clusters, RR Lyrae variable stars, Interstellar reddening
A Decade of Transit-timing Measurements Confirm Resonance in the K2-19 System. K2-19 is a star, slightly smaller than the Sun, that hosts three transiting planets. Two of these, K2-19 b and c, are between the size of Neptune and Saturn and have orbital periods near a 3:2 commensurability, and exhibit strong transit-timing variations (TTVs). A previous TTV analysis reported moderate eccentricities of ≍0.20 ± 0.03 for the two planets, but such high values would imply rapid orbital decay for the innermost planet d. Here, we present an updated analysis that includes eight new transit times from TESS, which extends the time baseline from three years to a decade, and employ a gradient-aware TTV modeling code. We confirm that the system resides in resonance with a small libration amplitude, but find a broader constraints on eccentricity that range from a few percent up to 0.2. These revised eccentricities alleviate previous concerns regarding rapid tidal circularization and support the long-term dynamical stability of the system.

Keywords: Exoplanet dynamics, Orbital resonances, Exoplanet astronomy, Transit timing variation method, Transit photometry
TIC 322208686: An Eclipsing System with γ Doradus Pulsations and a Third Component on a Wider Orbit. TIC 322208686 is known to be a detached binary that exhibits two types of variability: pulsation and eclipse. We present the physical properties of the target star using the short-cadence TESS data from sectors 24, 57, and 58, and our echelle spectra that show the presence of a tertiary companion. The spectral analysis led to the triple-lined radial velocities and the atmospheric parameters of the eclipsing components. Joint modeling of these observations reveals that the eclipsing pair contains two F-type stars with masses 1.564 ± 0.012M⊙ and 1.483 ± 0.012M⊙, radii 1.588 ± 0.011 R⊙ and 1.500 ± 0.012 R⊙, effective temperatures 7028 ± 100 K and 7020 ± 110 K, and luminosities 5.51 ± 0.32 L⊙and 4.90 ± 0.32 L⊙. The light contributions of the three stars obtained from this modeling match well with those calculated from the observed spectra. The binary star parameters are in satisfactory agreement with evolutionary model predictions for age t = 0.4 Gyr and metallicity Z = 0.03. We extracted 11 significant frequencies from the TESS light residuals with the binary effects removed. Of these, five signals between 0.65 day−1 and 1.89 day−1 can be considered as γ Dor pulsations originating mainly from the primary component, while the other frequencies are likely instrumental artifacts or combination terms. These results suggest that TIC 322208686 is a hierarchical triple, containing a pulsating eclipsing pair and a tertiary companion.

Keywords: Multiple stars, Stellar pulsations, Fundamental parameters of stars, Spectroscopic binary stars, Eclipsing binary stars, Gamma Doradus variable stars, Stellar evolution
Globular Clusters in the Galaxy Cluster MACS0416 at z = 0.397. We present a photometric analysis of globular clusters (GCs) in the massive galaxy cluster MACS J0416.1−2403 (z = 0.397) using deep JWST/NIRCam imaging from the PEARLS program. Point-spread function photometry was performed in the short wavelength filters, F090W, F115W, F150W, and F200W, yielding a catalog of ∼3 × 103 unresolved, point-like sources consistent with a GC population. Artificial-star tests indicate 80% completeness at F200W ≃ 30.36 mag. The color─magnitude diagrams show a narrow GC sequence well reproduced by PARSEC single-stellar-population models spanning ages of 5─9 Gyr and metallicities from [M/H] ≍ −2.0 to +0.2, consistent with evolved GC systems at this redshift. The GC luminosity function follows a log-normal form truncated by incompleteness at the faint end. The brightest sources extend slightly beyond the locus of classical GCs, suggesting a small number of ultracompact dwarf-like systems or stripped nuclei, while the bulk of the population exhibits the luminosities and colors expected for mature GCs at z ≃ 0.4.

Keywords: Globular star clusters, James Webb Space Telescope, Galaxy clusters, Photometry
Empirical Bolometric Correction and Zero-point Constants of Visual Magnitudes from High-resolution Spectra. A method of obtaining bolometric corrections (BCV) from observed high-resolution, high signal-to-noise spectra is described. The method is applied to the spectra of 128 stars collected from the literature with well-determined effective temperatures (Teff) with the Sλ(V) transparency profiles of Bessell and Landolt. The computed BCV values are found to be accurate within several millimagnitudes, and the effect of different Sλ(V) values is found to be no more than 0.015 mag. The measured visual-to-bolometric ratio (LV/L) from the sample spectra and classically determined BCV from bolometric (MBol) and visual (MV) absolute magnitudes helped us to determine the zero-point constant (C2) of the BCV scale. The determined C2 for each star for each Sλ(V) profile revealed C2 = 2.3653 ± 0.0067 mag if the Sλ(V) profile of Bessell is used and C2 = 2.3826 ± 0.0076 mag if the Sλ(V) profile of Landolt is used. Expanding CBol = 71.197425... mag and cBol = − 18.997351... mag announced by IAU2015GARB2, and using the definition of C2 = CBol─CV = cBol─cV, where capital C is the absolute magnitude and lowercase c is the apparent magnitude and subscripts indicate bolometric and visual, the zero-point constants—CV = 68.8321 ± 0.0067 mag and cV = −21.3627 ± 0.0067 mag, if LV and are in SI units—were determined corresponding to Sλ(V) of Bessell. The zero-point constants corresponding to Sλ(V) of Landolt are smaller, but the difference is not more than 0.02 mag. Typical and limiting accuracies for predicting a stellar luminosity from an apparent magnitude and a distance are analyzed.

Keywords: Bolometric correction, High resolution spectroscopy, Stellar physics, Fundamental parameters of stars
Magnetic Fields in Massive Star-forming Regions (MagMaR). VI. Magnetic Field Dragging in the Filamentary High-mass Star-forming Region G35.20─0.74N Due to Gravity. We investigate the magnetic field orientation and strength in the massive star-forming region G35.20-0.74N (G35), using polarized dust emission data obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) as part of the Magnetic fields in Massive star-forming Regions (MagMaR) survey. The G35 region shows a filamentary structure (a length of ∼0.1 pc) with six bright cores located along the filament's long axis. Magnetic field strengths across the G35 region range from 0.2 to 4.4 mG with a mean value of 0.8 ± 0.4 mG. The mass-to-flux ratio (λ) varies from 0.1 to 6.0, the critical value. The highest values are found locally around cores, whereas the remains of the filament are subcritical. A H13CO+ (3─2) velocity gradient of 29 km s−1 pc−1 is evident along the filament's long axis, aligned with the magnetic field direction. At larger scales (∼0.1 pc), the magnetic field lines appear roughly perpendicular to the filament's long axis, in contrast to the smaller-scale structure (∼0.003 pc) traced by ALMA. The magnetic field lines could be dragged along the filament as a result of the gas motion induced by the gravitational potential of the filament. Six cores in the filament have similar spacings between 0.02 and 0.04 pc. The initial filament fragmentation could have produced a core spacing of 0.06 pc, following filament fragmentation theory, and the current core spacing is the result of cores comoving with the gas along the filament. This core migration could occur in a few 104 yr, consistent with high-mass star formation timescales.

Keywords: Massive stars, Star forming regions, Polarimetry, Star formation, Dust continuum emission, Interstellar medium, Magnetic fields
The FAST-SETI Milky Way Globular Cluster Survey. I. A Pilot Multibeam On-the-fly Search of Five Globular Clusters at the L Band. We report a narrowband technosignature search toward five Milky Way globular clusters—NGC 6171, NGC 6218, NGC 6254, NGC 6838, and IC 1276—using Five-hundred-meter Aperture Spherical radio Telescope (FAST)'s 19 beam L-band receiver (1.05─1.45 GHz). We adapted MultiBeam Point-source Scanning (MBPS) to extended targets by gating detections to generalized on-target windows (gOTWs), i.e., the time intervals when a beam's main lobe intersects a buffered cluster mask, and by enforcing the deterministic multibeam illumination sequence as a geometry test. Spectra at ∆ν ≍ 7.5 Hz resolution and ∆t ≍ 10 s cadence were searched with turboSETI over  ∣ν̇∣≤4Hzs−1  at S/N ≥ 10. From 2.75 × 105 raw hits across both linear polarizations, none survived the gOTW gating, array-wide simultaneity veto, in-stripe ordering, and single-drift coherence checks, yielding a robust null result. With SEFD ≍ 1.5 Jy and an effective ∼60 s per illuminated crossing, our per-crossing flux density threshold is  Smin≍0.50  Jy, corresponding to  EIRPmin≍(0.72─1.8)×1016  W for cluster distances of 4─6.5 kpc; when multiple illuminated crossings occur, noncoherent stacking improves sensitivity by up to  N . To our knowledge, this is the first FAST technosignature survey dedicated to globular clusters and the first to use MBPS as the primary observing strategy. These limits disfavour bright, persistent, isotropic L-band beacons above the stated thresholds during our epochs and establish a scalable blueprint—geometry-aware gating and verification—for multiepoch MBPS campaigns that expand signal morphologies and combine passes to deepen constraints on transmitters in dense stellar systems.

Keywords: Search for extraterrestrial intelligence, Technosignatures, Astrobiology, Star clusters
Sloan Digital Sky Survey. V. Pioneering Panoptic Spectroscopy. The Sloan Digital Sky Survey V (SDSS-V) is pioneering panoptic spectroscopy: it is the first all-sky, multiepoch, optical-to-infrared spectroscopic survey. SDSS-V is mapping the sky with multiobject spectroscopy (MOS) at telescopes in both hemispheres (the 2.5 m Sloan Foundation Telescope at Apache Point Observatory and the 100-inch du Pont Telescope at Las Campanas Observatory), where 500 zonal robotic fiber positioners feed light from a wide-field focal plane to an optical (R ∼ 2000, 500 fibers) and a near-infrared (R ∼ 22,000, 300 fibers) spectrograph. In addition to these MOS capabilities, the survey is pioneering ultra─wide-field (∼4000 deg2) integral field spectroscopy enabled by a new dedicated facility (LVM-I) at Las Campanas Observatory, where an integral field spectrograph (IFS) with 1801 lenslet-coupled fibers arranged in a 0 .° 5-diameter hexagon feeds multiple R ∼ 4000 optical spectrographs that cover 3600─9800 Å. SDSS-V's hardware and multiyear survey strategy are designed to decode the chemodynamical history of the Milky Way and tackle fundamental open issues in stellar physics in its Milky Way Mapper program, trace the growth physics of supermassive black holes in its Black Hole Mapper program, and understand the self-regulation mechanisms and the chemical enrichment of galactic ecosystems at the energy injection scale in its Local Volume Mapper program. The survey is well timed to multiply the scientific output from major all-sky space missions. The SDSS-V MOS programs began robotic operations in 2021; IFS observations began in 2023 with the completion of the LVM-I facility. SDSS-V builds on decades of heritage of SDSS's pioneering advances in data analysis, collaboration spirit, infrastructure, and product deliverables in astronomy.

Keywords: Black hole physics, Galaxy formation, Sky surveys, Milky Way formation, Galaxy physics, Stellar physics, Interstellar medium, Automated telescopes, Ground telescopes
The First Direct Occurrence Rate Estimates for Kepler Exoplanets in Small-separation Binary Star Systems: Planet Occurrence Is Suppressed in Binary Stars. Exoplanet occurrence rates facilitate comparisons between observations of planets and theoretical models of planet formation. Despite their deductive power, exoplanet occurrence rates for half the stars in the sky are missing because occurrence rate studies systematically exclude binary star systems. We assembled a large sample of high-likelihood binaries from the Kepler mission to calculate occurrence rates for circumstellar (S-type) planets in small-separation binary star systems (≲100 au) for the first time. For a sample of high-likelihood small-separation binaries, we found binaries to host 58% fewer planets per system than single stars to 11.4σ significance within 1─4 R⊕ and 1─50 days, and 50% fewer planets compared to single stars when integrating over the full parameter space of 1─10 R⊕ and 1─100 days to 3.8σ significance. We found no evidence for a radius valley or radius cliff, instead detecting a smooth decline in planet occurrence with increasing planetary radius. The difference between the single-star planet radius distribution and the binary-star planet radius distribution is 4.3σ significant from a Kolmogorov─Smirnov test. These results suggest significantly different planet formation and survival outcomes in binaries compared to single stars, and support other studies that have measured a deficit of observed planets in binary star systems.

Keywords: Binary stars, Exoplanets, Astrostatistics