Sazuna/UAT_keywords huggingface dataset:
Observational Constraints on the Radial Evolution of O<SUP>6+</SUP> Temperature and Differential Flow in the Inner Heliosphere. Over decades of solar wind observations, heavy ions have been observed to have a higher temperature and flow faster than protons in the solar corona and heliosphere. Remote observations have largely been limited to the low corona (&lt;4 R⊙), while in situ observations for heavy ions (Z &gt; 2) have only been sampled at 1 au and beyond. As a result, theories that address heavy ion heating and acceleration remain largely unconstrained. With the launch of Solar Orbiter, heavy ion kinetics can be probed closer to the Sun, as close as the orbit of Mercury (65 R⊙), to examine their radial behavior. Through a statistical analysis of O6+, this work provides a comprehensive analysis of the velocity and temperature of O6+ from 0.3 to 1 au. The study finds that the O6+ relative drift, normalized to the local Alfvén speed, and its temperature compared to protons both decrease with distance from the Sun and show some speed dependence. The O6+ temperature is well fit by a single temperature adiabatic profile across all wind speeds, suggesting that there is no significant heating at these heliocentric distances, which is in contrast to what is observed for protons and He2+. Alfvénic fluctuations, some with full 180∘ field rotation, create momentary negative differential streaming where the speed of O6+ trails the protons. The amount of negative differential streaming gradually increases at larger distances. These results provide critical constraints on the proposed mechanisms seeking to describe ion heating and acceleration in the solar wind.

Keywords: Space plasmas, Solar wind, Alfven waves, Chemical abundances
An Upper Limit of 10<SUP>6</SUP> M<SUB>⊙</SUB> in Dust from ALMA Observations in 60 Little Red Dots. By virtue of their red color, the dust in little red dots (LRDs) has been thought to be of appreciable influence, whether that dust is distributed in a torus around a compact active galactic nucleus or diffuse in the interstellar medium of nascent galaxies. In C. M. Casey et al. we predicted that, based on the compact sizes of LRDs (unresolved in JWST NIRCam imaging), detection of an appreciable dust mass would be unlikely. Here we present follow-up Atacama Large Millimeter/submillimeter Array 1.3 mm continuum observations of a sample of 60 LRDs drawn from H. B. Akins et al. None of the 60 LRDs are detected in imaging that reaches an average depth of σrms = 22 μJy. A stack of the 60 LRDs also results in a nondetection, with an inverse-variance weighted flux density measurement of S1.3 mm = 2.1 ± 2.9 μJy. This observed limit translates to a 3σ upper limit of 106 M⊙ in LRDs' dust mass, and ≲1011 L⊙ in total dust luminosity; both are a factor of 10× deeper than previous submillimeter stack limits for LRDs. These results are consistent with either the interpretation that LRDs are reddened due to compact but modest dust reservoirs (with AV ∼ 2─4) or, alternatively, that instead of being reddened by dust, they have extreme Balmer breaks generated by dense gas (&gt;109 cm−3) enshrouding a central black hole.

Keywords: Interstellar dust, Interstellar reddening, High-redshift galaxies, Astrophysical black holes
Detection of Young Massive White Dwarfs in Core-collapsed Globular Cluster NGC 362. Core-collapsed globular clusters are ideal targets to explore the presence of stellar collision products. Here, we have studied 17 far-UV bright white dwarf (WD) members in the globular cluster NGC 362 using data obtained from the Ultra Violet Imaging Telescope (UVIT) mounted on AstroSat and from the Hubble Space Telescope. Multiwavelength spectral energy distributions (SEDs) are analyzed using UV and optical data sets to characterize and determine the parameters of WDs. Fourteen of the WDs fit single-component SEDs well, while three showed a good fit with a two-component SED model, indicating a binary system comprising a WD and a low-mass main-sequence (MS) star. The effective temperatures, radii, luminosities, and masses of WDs are in the ranges 22,000─70,000 K, 0.008─0.028 R⊙, 0.09─3.0 L⊙, and 0.30─1.13 M⊙, respectively. The effective temperatures, radii, luminosities, and masses of the companions (low-mass MS stars) are 3500─3750 K, 0.150─0.234 R⊙, 0.003─0.01 L⊙, and 0.14─0.24 M⊙, respectively. The three binary systems (WD-MS), along with the massive WDs, may have formed through dynamical processes that occurred during the core collapse of the cluster. This is the first evidence of a massive WD formation in a core-collapsed cluster, which is the missing link in the formation of a fast radio burst (FRB) progenitor in a globular cluster. This study provides evidence that NGC 362 hosts stellar systems that may evolve into exotic stars such as Type Ia supernovae and/or FRBs in the future. This Letter is paper VI of the Globular Cluster UVIT Legacy Survey.

Keywords: M dwarf stars, White dwarf stars
Discovery of the Second Y+Y Dwarf Binary System: CWISEP J193518.59-154620.3. We present the discovery of a companion to the Y dwarf, CWISEP J193518.59–154620.3, the second Y-Y dwarf binary detected to date. Y dwarfs are the coldest known free-floating objects (&lt;500 K) and, on average, represent the lowest mass objects directly formed through turbulent fragmentation of a molecular cloud. Studying their multiplicity allows us to place strong constraints on the ability to form multiple systems of planetary masses and approach the opacity limit of fragmentation. Due to their physical properties, Y dwarfs also serve as analogs to gas giant planets. CWISEP J193518.59–154620.3 has been shown to have a unique methane emission feature in its near-infrared spectrum at 3.326 μm, potentially indicative of auroral processes without a clear origin. CWISEP J193518.59–154620.3 was observed with JWST's MIRI in the F1000W, F1280W, and F1800W filters. We applied a point-spread function (PSF) fitting algorithm using empirically derived PSF models and resolved a companion in the F1000W and F1280W filters separated by 172 mas and 2.48 au, assuming a distance of 14.43 pc. Using the ATMO2020 evolutionary models, we estimate a mass of 12–39 MJup for the primary and 7–24 MJup for the companion, assuming an age of 1–10 Gyr for a mass ratio of 0.55–0.62, resulting in an estimated period of 16–28 yr. It is unknown which component of this binary exhibits the methane emission feature. We also resolve known companions WISE J014656.66+423410.0B and WISE J171104.60+350036.8B using MIRI data and present their F1000W and F1280W photometry.

Keywords: James Webb Space Telescope, Brown dwarfs, Y dwarfs, High angular resolution
High-resolution Observation of Solar Prominence Plumes Induced by Enhanced Spicular Activity. Solar prominences are the most prominent large-scale structures observed above the solar limb in emission in chromospheric lines but in absorption in coronal lines. At the bottom of prominences often appears a bubble, with plumes occasionally rising from the prominence–bubble interface. The plumes may potentially play an important role in the mass supply and thermodynamic evolution of prominences, but their nature and generation mechanism are elusive. Here we use the high-resolution Hα observations obtained by the New Vacuum Solar Telescope to investigate a quiescent prominence with bubbles and plumes on 2022 November 8. Within an interval of about 2 hr, enhanced spicular activity disturbs the prominence–bubble interface, producing bursts of small-scale plumes rising through the prominence. Characterized by clustered spicules jetting at higher speeds (sometimes exceeding the typical chromospheric Alfvén speed) and longer lifetime (over 15 minutes), the enhanced spicular activity differs markedly from regular spicules. We hence conjecture that the enhanced spicular activity may drive shock waves, which trigger the magnetic Richtmyer–Meshkov instability at the prominence–bubble interface, leading to the formation of small-scale plumes. These observations provide evidence that the enhanced spicular activity plays a potentially important role in the dynamic evolution of bubbles and plumes, thereby participating in the mass supply of solar prominences.

Keywords: Solar spicules, Solar chromosphere, Solar prominences
Near-discovery Observations of Interstellar Comet 3I/ATLAS with the NASA Infrared Telescope Facility. Interstellar objects are comets and asteroids that formed around other stars but were ejected before they could accrete into exoplanets. They therefore represent a rare opportunity to compare the the building blocks of planets in the solar system to those in other stellar systems. The third interstellar object, 3I/ATLAS, is the newest, brightest, potentially largest, and fastest member of this population. We report observations of 3I/ATLAS taken on 2025 July 3 and 4 with the NASA Infrared Telescope Facility just days after its discovery. In  r' -band imaging with 'Opihi, we see no obvious lightcurve variability and derive a  g'‑i'  color of 0.98 ± 0.03, which is consistent in spectral slope to other near-discovery observations. We obtained the first near-infrared (NIR) reflectance spectrum of 3I/ATLAS with SpeX. The visible color and NIR spectrum show a linear, red visible slope, a somewhat less red slope between 0.7 and 1.1 μm, and a neutral or slightly blue slope at longer wavelengths. Challenges in modeling the reflectivity of 3I may indicate that this comet has a complex grain size distribution, grain compositions unlike solar system comets, or both. Like 2I/Borisov, there are no obvious signatures of water ice in the coma of 3I/ATLAS. Observations closer to perihelion will help elucidate whether 3I has less water than anticipated or whether the interstellar objects might retain and release their ices somewhat differently from solar system comets.

Keywords: Interstellar objects
The Impact of Organic Hazes and Graphite on the Observation of CO<SUB>2</SUB>-rich Sub-Neptune Atmospheres. Many sub-Neptune and super-Earth exoplanets are expected to develop metal-enriched atmospheres due to atmospheric loss processes such as photoevaporation or core-powered mass loss. Thermochemical equilibrium calculations predict that at high metallicity and a temperature range of 300–700 K, CO2 becomes the dominant carbon species, and graphite may be the thermodynamically favored condensate under low-pressure conditions. Building on prior laboratory findings that such environments yield organic haze rather than graphite, we measured the transmittance spectra of organic haze analogs and graphite samples and computed their optical constants across the measured wavelength range from 0.4 to 25 μm. The organic haze exhibits strong vibrational absorption bands, notably at 3.0, 4.5, and 6.0 μm, while graphite shows featureless broadband absorption. The derived optical constants of haze and graphite provide the first data set for organic haze analogs formed in CO2-rich atmospheres and offer improved applicability over prior graphite data derived from bulk reflectance or ellipsometry. We implemented these optical constants into the Virga and PICASO cloud and radiative transfer models to simulate transit spectra for GJ 1214b. The synthetic spectra with organic hazes reproduce the muted spectral features in the near-infrared observed by Hubble and general trends observed by JWST for GJ 1214b, while graphite models yield flat spectra across the observed wavelengths. This suggests haze features may serve as observational markers of carbon-rich atmospheres, whereas graphite's opacity could lead to radius overestimation, offering a possible explanation for superpuff exoplanets. Our work supplies essential optical to infrared data for interpreting observations of CO2-rich exoplanet atmospheres.

Keywords: Exoplanet atmospheric composition , Laboratory astrophysics, Exoplanet atmospheres, Transmission spectroscopy
Tidal Suppression of Fuzzy Dark Matter Heating in Milky Way Satellite Galaxies. Many previous studies have imposed stringent constraints on the particle mass of fuzzy dark matter (FDM) by analyzing observations of Galactic satellite galaxies, which show no significant evidence of the heating effect predicted by FDM. However, these analyses have generally neglected the tidal influence of the Milky Way (MW), which can substantially suppress the FDM-induced heating effect in satellites. This oversight arises from computational challenges of accurately capturing the tidal effects in FDM simulations. In this study, we present a novel simulation framework that, for the first time, enables the simulation of an FDM-stellar system within an observationally motivated gravitational potential of the MW. This framework incorporates the diverse Galactic components, including the gravitational influence of the Large Magellanic Cloud. Using the Fornax dwarf galaxy as a case study, we demonstrate that tidal effects significantly alleviate the tension between observational data and the predicted heating effect for an FDM particle mass of ma ∼ 10‑22 eV.

Keywords: Galaxy dark matter halos, Dwarf galaxies, Dark matter
Early Shock Cooling Observations and Progenitor Constraints of Type IIb Supernova SN 2024uwq. We present early multiwavelength photometric and spectroscopic observations of the Type IIb supernova SN 2024uwq, capturing its shock-cooling emission phase and double-peaked light-curve evolution. Early spectra reveal broad Hα (v ∼ 15,500 km s−1) and He I P Cygni profiles of similar strengths. Over time the He I lines increase in strength while the Hα decreases, consistent with a hydrogen envelope (Menv = 0.7─1.35 M⊙) overlying helium-rich ejecta. Analytic modeling of early shock cooling emission and bolometric light analysis constrains the progenitor to a partially stripped star with radius R = 10─60 R⊙, consistent with a blue/yellow supergiant with an initial zero-age main-sequence mass of 12─20 M⊙ likely stripped via binary interaction. SN 2024uwq occupies a transitional position between compact and extended Type IIb supernovae, highlighting the role of binary mass transfer efficiency in shaping a continuum of stripped-envelope progenitors. Our results underscore the importance of early UV/optical observations to characterize shock breakout signatures critical to map the diversity in evolutionary pathways of massive stars. Upcoming time-domain surveys, including Rubin Observatory's LSST and UV missions like ULTRASAT and UVEX, will revolutionize our ability to systematically capture these early signatures, probing the full diversity of stripped progenitors and their explosive endpoints.

Keywords: Binary stars, Supernovae, Core-collapse supernovae, Stellar evolution
Growing the Intermediate-mass Black Hole in Omega Centauri. The recent detection of fast-moving stars in the core of Omega Centauri (ω Cen), the most massive globular cluster (GC) in the Milky Way, has provided strong evidence for the presence of an intermediate-mass black hole (IMBH). As ω Cen is likely the accreted nucleus of a dwarf galaxy, this IMBH also represents a unique opportunity to study black hole (BH) seeding mechanisms and their potential role in the formation of supermassive BHs. We present Monte Carlo N-body models of ω Cen with detailed treatments for the loss-cone dynamics involving stars, binaries, and compact objects. Starting with BH seeds of 500–5000 M⊙ (consistent with runaway collisions of massive stars), our cluster models grow IMBHs with masses of ∼50,000 M⊙ after 12 Gyr, while successfully reproducing the present-day surface brightness and velocity dispersion profiles of ω Cen. We find a population of fast stars similar to those observed in the core of ω Cen, with the fastest stars originating from binaries that were tidally disrupted by the IMBH. The IMBH growth is primarily driven by mergers with 30–40 M⊙BHs, suggesting a present-day IMBH–BH merger rate of ∼(4–8) × 10‑8 yr‑1 in ω Cen–like GCs. Our models also predict a similar rate of tidal disruption events (TDEs; ∼5 × 10‑8 yr‑1), which, depending on the frequency of ω Cen–like GCs per galaxy, may represent anywhere from 0.1% to 10% of the observed TDE rate.

Keywords: Globular star clusters, Intermediate-mass black holes, Binary stars, Black holes, Monte Carlo methods, Tidal disruption, Stellar dynamics, Gravitational waves, Compact objects, Runaway stars, N-body simulations, Star clusters
Discovery of Hα Emission from a Protoplanet Candidate around the Young Star 2MASS J16120668─3010270 with MagAO-X. 2MASS J16120668─3010270 (hereafter 2MJ1612) is a young M0 star that hosts a protoplanetary disk in the Upper Scorpius star-forming region. Recent Atacama Large Millimeter/submillimeter Array (ALMA) observations of 2MJ1612 show a mildly inclined disk (i = 37°) with a large dust-depleted gap (Rcav ≍ 0 .″ 4 or 53 au). We present high-contrast Hα observations from MagAO-X on the 6.5 m Magellan telescope and new high-resolution submillimeter dust continuum observations with ALMA of 2MJ1612. On both 2025 April 13 and 16, we recovered a point source with Hα excess with a signal-to-noise ratio ≳5 within the disk gap in our MagAO-X angular and spectral differential images at a separation of 141.96 ± 2.10 mas (23.45 ± 0.29 au deprojected) from the star and a position angle of 159 .° 00 ± 0 .° 55. Furthermore, this Hα source is within close proximity to a K-band point source in the SPHERE/IRDIS observation taken on 2023 July 21. The astrometric offset between the K band and Hα source can be explained by orbital motion of a bound companion. Thus, our observations can be best explained by the discovery of an accreting protoplanet, 2MJ1612 b, with an estimated mass of 4 MJup and a Hα line flux ranging from (29.7 ± 7.5) × 10−16 erg s cm2 to (8.2 ± 3.4) × 10−16 erg s cm2. 2MJ1612 b is likely the third example of an accreting Hα protoplanet responsible for carving the gap in its host disk, joining PDS 70 b and c. Further study is necessary to confirm and characterize this protoplanet candidate and to identify any additional protoplanets that may also play a role in shaping the gap.

Keywords: Exoplanet astronomy, Exoplanet formation, Direct imaging, Adaptive optics
A Unified Picture of Swirl-driven Solar Coronal Heating: Magnetic Energy Supply and Dissipation. The coronal heating problem is one of the most critical challenges in solar physics. Recent observations have revealed that small-scale swirls are ubiquitous in the photosphere and chromosphere, suggesting that they may play a significant role in transferring magnetic energy into the corona. However, the overall contribution of swirls to the total magnetic energy supply and subsequent coronal heating remains uncertain. To address this, we perform statistical analyses of simulated swirls using a three-dimensional radiative magnetohydrodynamic simulation extending from the convection zone to the corona in the quiet Sun. Our results reveal that swirls account for approximately half of the total magnetic energy. Furthermore, they strongly suggest that swirls can trigger coronal heating events through magnetic reconnection. The occurrence frequency of these events follows a power-law-like distribution, consistent with observations of coronal heating signatures known as "nanoflares," indicating that swirls are promising candidates as their drivers.

Keywords: Radiative magnetohydrodynamics, Solar coronal heating, Alfven waves, Solar corona
Cosmic Cascades: How Disk Substructure Regulates the Flow of Water to Inner Planetary Systems. The influx of icy pebbles to the inner regions of protoplanetary disks constitutes a fundamental ingredient in most planet formation theories. The observational determination of the magnitude of this pebble flux and its dependence on disk substructure (disk gaps as pebble traps) would be a significant step forward. In this work, we analyze a sample of 21 T Tauri disks (with ages ≍0.5─2 Myr) using JWST/MIRI spectra homogeneously reduced with the JDISCS pipeline and high-angular-resolution Atacama Large Millimeter/submillimeter Array (ALMA) continuum data. We find that the 1500/6000 K water line flux ratio measured with JWST—a tracer of cold water vapor and pebble drift near the snow line—correlates with the radial location of the innermost dust gap in ALMA continuum observations (ranging from 8.7 to 69 au), confirming predictions from recent models that study connections between the inner and outer disk reservoirs. We develop a population synthesis exploration of pebble drift in gapped disks and find a good match to the observed trend for early and relatively effective gaps, while scenarios where pebble drift happens quickly, gaps are very leaky, or where gaps form late, are all disfavored on a population level. Inferred snow line pebble mass fluxes (ranging between 10−6 and 10−3 M⊕ yr−1 depending on gap position) are comparable to fluxes used in pebble accretion studies and those proposed for the inner solar system, while system-to-system variations suggest differences in the emerging planetary system architectures and water budgets.

Keywords: Infrared spectroscopy, Astrochemistry, Protoplanetary disks, Circumstellar disks, Planet formation
Meridional Circulation Molecular-weighted. Meridional circulation in stratified stellar/planetary interiors in the presence of stable molecular-weight gradients remains poorly understood, thereby affecting angular momentum transport in evolutionary models. We extend the downward control principle of atmospheric sciences to include compositional stratification. Using a linearized analysis, we show that stable μ-gradients slow down the penetration of circulation into the depths, emphasizing the importance of time-dependent solutions. However, additional effects such as horizontal turbulence or magnetic fields are needed to halt it completely. We also find limits demarcating linear and nonlinear regimes in terms of Schmidt and Rossby numbers. Nonlinear simulations exhibit compositional mixing due to meridional currents, enabling deeper penetration than otherwise. We propose slowly evolving and steady-state scenarios for the solar tachocline, and helioseismically observed heavy element abundances, while acknowledging the absence of constraints on the radial variation of the Schmidt number. In the context of stellar evolution, differential rotation profiles of solar-type main-sequence stars may follow analytical solutions extending from D. Banik &amp; K. Menou, thereby aiding further probes into magneto/hydrodynamic instabilities and outward angular momentum transport.

Keywords: Stellar interiors, Solar radiative zone, Solar interior, Solar physics, Solar meridional circulation, Stellar rotation
Broadband Spectral Modeling of Prompt Emission from Gamma-Ray Bursts Observed by the Transiting Exoplanet Survey Satellite. Optical observations of gamma-ray bursts (GRBs) contemporaneous with their prompt high-energy emission are rare, but they can provide insights into the physical processes underlying these explosive events. The Transiting Exoplanet Survey Satellite's (TESS's) large field of view and continuous observation capabilities make it uniquely positioned to detect and characterize prompt optical flashes from GRBs. In this work, we fit phenomenological models to the gamma-ray through optical spectral energy distributions (SEDs) of 24 bursts with arcsecond-level localizations that fell within the TESS field of view between 2018 July and 2024 December. In four cases, the extrapolation of the high-energy SED agrees with the observed optical flux to within 1σ. In one case, there is a significant excess of optical flux relative to the extrapolation. In two cases, upper limits from TESS did not constrain the optical portion of the SED. In the remaining 17 cases, the optical flux is overpredicted by the extrapolation from high energies. This discrepancy could be explained by dust extinction in the host galaxy.

Keywords: Gamma-ray bursts, Sky surveys