Sazuna/UAT_keywords huggingface dataset:
More Old Dogs, More New Tricks: Photographic Plates of the Globular Cluster M10 (NGC 6254) Digitized with a Commercial Scanner. Photographic plates of the globular cluster M10 (NGC 6254) that were recorded at the Dominion Astrophysical Observatory between 1931 and 1934 have been digitized with a commercial scanner. The plates have numerous cosmetic issues, and the results are used to assess the information that can be extracted from such archival data. After performing a series of basic processing steps, a plate-to-plate dispersion in photometric measurements of ≤10% is delivered between V = 13 and 15. The light curves of known variables are constructed and evidence is presented for long-term variations in the mean brightnesses of the W Vir star V3, as well as the semiregular (SR) variable V29. Two new variable stars are identified, although cluster membership is likely for only one of these. A brightness-selected sample of candidate variable stars identified in the Gaia database that are not in the General Catalogue of Variable Stars is also examined, and some show variability in the plate photometry. Parallaxes indicate that five of the Gaia variables are at the same distance as M10. Four of the Gaia variables fall along the horizontal branch of M10 on the color–magnitude diagram. Another Gaia variable is located close to the cluster center and may be evolving on the supra–horizontal branch. The plate photometry suggests that the Gaia variable with the most secure M10 membership based on parallax, proper motions, and velocity is an SR variable that is offset by a projected distance of 9 pc from the cluster center.

Keywords: Globular star clusters, Photographic photometry, Irregular variable stars, Pulsating variable stars
Deep Learning for Position Angle Quantification Applied to Interstellar Filaments. Studying filamentary structures opened a door for understanding the conditions of star formation and interstellar medium properties. Present-day algorithms for identifying filaments and their orientations require careful individual parameterization for each astronomical map. The increasing scale of astronomical surveys presents significant challenges in handling larger data sets. While previous data resources have been sufficient, there is a growing demand for more extensive data sets to support advanced research. The construction of new astronomical facilities will substantially increase the volume of data available for exploration. For example, the Square Kilometre Array—the largest radio telescope project to date—will enable detailed mapping of the large-scale structure of the cosmos, including filaments, so the astronomical community is expected to process enormous amounts of data. In this study, we show the efficiency of a parameterization-free approach based on the U-Net convolutional neural network. We trained our model on a synthetically generated data set and tested it on observational data. Our method achieves a validation mean squared error of 7.73, demonstrating improved accuracy over existing approaches. The modular separation of preprocessing and angle determination makes it adaptable to different data sets. The variety of filamentary structures in the synthetic data set allows us to reproduce the multifariousness encountered in observational data. The resulting open-access model provides an efficient solution for position angle determination and filamentary structures identification that can be applied to large data sets.

Keywords: Convolutional neural networks, Interstellar filaments
Requirements for Joint Orbital Characterization of Cold Giants and Habitable Worlds with Habitable Worlds Observatory. We determine optimal requirements for the joint detection of habitable-zone planets and cold giant planets with the Habitable Worlds Observatory (HWO). Analysis of 164 nearby stars shows that a coronagraph outer working angle of 1440 milliarcseconds (mas) is necessary to achieve 80%–90% visibility of cold giants. Approximately 40 precursor radial velocity (RV) measurements with 1 m s‑1 precision are required to adequately constrain orbital parameters before HWO observations. We demonstrate that six to eight astrometric measurements and 40 RV measurements distributed across the mission timeline, compared to RV constraints alone and to astrometry constraints alone, significantly improve orbital parameter precision, enabling direct determination of orbital inclination with uncertainties of &lt;3°. For habitable-zone planet characterization, four to five epochs provide moderate confidence, while high-confidence (95%) confirmation requires eight of more observations. These specifications are essential for the comprehensive characterization of planetary system architectures and understanding the potential habitability of terrestrial exoplanets.

Keywords: Exoplanet dynamics, Exoplanet astronomy, Space telescopes, Telescopes, Dynamical evolution
The Effects of Sunspots on Spectral Line Shapes in the Visible. We present a comparative spectral analysis to explore the ability of a cooler Sun model to accurately capture the spectral line shape changes caused by sunspots. In the search for small Earth-like planets, the effects of stellar surface activity can overwhelm the ∼10 cm s−1 planetary radial velocity signal. This necessitates the development of new stellar modeling methods and a greater understanding of the impact of surface activity on stellar spectra. Some attempts to model out noise from sunspot activity, in particular, have used a sum of a stellar model with a model of a cooler, but otherwise identical star. From our analysis, we find that a cooler effective temperature alone cannot capture the numerous spectral line shape variations seen in a sunspot observation. The cooler temperature of a sunspot not only deepens the cores of atomic lines, but it also increases and strengthens molecular lines that are not fully represented in our line list. Furthermore, our LTE models and a comparison cool star also fail at capturing line strengthening, broadening, blending, and splitting induced by the magnetic field in the sunspot.

Keywords: Starspots, Sunspots, Radial velocity, Stellar activity, Solar activity, Exoplanet detection methods
Predicting Exoplanet Occurrence Using Association Analysis. Over the past few decades, a remarkable surge in exoplanet discoveries has led to a substantial increase in available data. As of this writing, over 5000 exoplanets have been confirmed, with thousands more expected from current and future observatories. This wealth of data calls for a need to efficiently and thoroughly process complex exoplanetary data sets in order to identify significant trends and gain insights into the characteristics of exoplanets. In this paper, we demonstrate the advantage of leveraging machine learning to understand exoplanet occurrence and formation based on patterns observed within astronomical data. We use a technique called association analysis to identify frequent co-occurring planet subtypes in thousands of exoplanetary systems and generate association rules. We then explore the association rules derived from our algorithm to discover and understand the significant patterns found in the data. For instance, one of our rules shows that a planetary system with a stellar spectral type of "M" and containing a temperate gas giant (≥200 and &lt;400 K) tends to also include a cold gas giant (&lt;200 K). Our findings include rules that predict the presence of cold and long-period gas giants in systems with G and M dwarf stars, despite observational biases against detecting such planets. Additionally, we uncovered patterns suggesting the potential presence of temperate gaseous planets, which are of interest to astrobiology. Overall, this project establishes a valuable and extendable framework for future research, with its predictive power expected to grow along with the continually increasing abundance of exoplanet data.

Keywords: Astronomy data visualization, Astronomy data analysis, Exoplanet systems, Exoplanets
Unveiling the Atmosphere of HR 7672 B from the Near-infrared High-resolution Spectrum Using REACH/Subaru. Characterizing the atmospheres of exoplanets and brown dwarfs is crucial for understanding their atmospheric physics and chemistry, searching for biosignatures, and investigating their formation histories. Recent advances in observational techniques, combining adaptive optics with high-resolution spectrographs, have enabled detailed spectroscopic analysis for directly imaged faint companions. In this paper, we report an atmospheric retrieval on the L-type brown dwarf HR 7672 B using a near-infrared high-contrast high-resolution spectrograph, REACH (Y, J, H band, R ∼ 100,000), which combines SCExAO with IRD at the Subaru Telescope. Our model, developed based on the ExoJAX spectrum code, simultaneously accounts for several factors, including the presence of clouds in the L dwarf's atmosphere as well as contamination from the host star's light and telluric absorption lines in the observed spectra. Our analysis identified H2O and FeH as the primary absorbers in the observed J- and H-band spectra. Additionally, the observed features were reproduced with a model that includes cloud opacity, assuming an optically thick cloud at the pressure Ptop. The resulting temperature at the cloud top pressure suggests the potential formation of clouds composed of TiO2, Al2O3, or Fe. This study is the first science demonstration for faint spectra obtained by REACH, providing a foundation for future investigations into the atmospheres of exoplanets and brown dwarfs.

Keywords: High resolution spectroscopy, Exoplanets, Brown dwarfs, Exoplanet atmospheres
A Homogeneous Catalog of Oscillating Solar-type Stars Observed by the Kepler Mission and a New Amplitude Scaling Relation Including Chromospheric Activity. We present a homogeneous catalog of global asteroseismic parameters and derived stellar parameters for 765 Kepler main-sequence and subgiant stars. The catalog was produced by reanalyzing all available Kepler DR25 short-cadence data using pySYD, an automated pipeline to extract global asteroseismic parameters. We find 50 new detections, seven of which are also planet candidate host stars. We find excellent agreement between our νmax and Δν measurements and literature values, with an average offset of 0.2% ± 0.4% (σ = 5%) and 0.2% ± 0.7% (σ = 2%), respectively. In addition, we derive stellar radii and masses with an average precision of 2.7% and 10.4%, respectively, and find a mean offset of 0.8% ± 0.2% (σ = 6%) between our radii derived with asteroseismology and those from Gaia parallaxes. Using spectroscopic  logRHK'  activity measurements from Keck/High Resolution Echelle Spectrometer (HIRES), we derive an amplitude scaling relation with an activity term for main-sequence and subgiant stars, which successfully predicts amplitudes with a precision of ≈8%–9%. Our work is the largest and most homogeneous asteroseismic catalog of Kepler main-sequence and subgiant stars to date, including a total of 101 stars hosting planet candidates and 451 stars with measured rotation periods.

Keywords: Fundamental parameters of stars, Stellar oscillations, Asteroseismology, Photometry
BSN. II. The First Light Curve Study of Eight Total Eclipsing Contact Binary Stars with Shallow Fillout Factors. This study provides the first comprehensive analysis of eight total-eclipse W Ursae Majoris-type contact binary systems. Ground-based photometric multiband observations were conducted at a Mexican observatory, and new times of minima were extracted. The O–C analysis reveals that four of our target binaries exhibit a long-term increase in their orbital periods, while the others show a long-term decrease in their orbital periods. We analyzed the light curves using the PHOEBE Python code and BSN application. Among the target systems, two required the inclusion of a cold starspot on one of the components to achieve an adequate fit. The light curve analysis revealed that the target systems exhibit a shallow fillout factor. Absolute parameters were estimated using the Gaia DR3 parallax and astrophysics equations. Considering the effective temperatures and component masses, each system was classified as either the A- or W-subtype. The stellar evolution of the systems was represented through the mass–radius and mass–luminosity diagrams. Additionally, we calculated the initial masses of the companion stars and the total mass lost for each target system.

Keywords: Eclipsing binary stars, Astronomy data analysis, Fundamental parameters of stars, Close binary stars
Modeling the Optical Impact of the Second-generation Starlink Satellite Constellation. The optical impact of Starlink is of great concern and the Gen1 network is well studied. However, understanding of the planned second-generation (Gen2) constellation containing almost 30,000 satellites with two thirds in very low Earth orbit (VLEO) below 450 km is developing. This work models Gen2 orbital parameters and considers line-of-sight visibility and spacecraft illumination in relation to terrestrial latitude and investigates changes through the day/night transition period. At peak latitudes there will be over 1200 satellites illuminated above the naked-eye horizon that persist long into the local winter night. At higher latitudes in summer spacecraft may then remain illuminated during darkness hours without interruption. For optical astronomy around 90% will be below the observational horizon, still leaving up to 120 in the field of view. Of those illuminated at nightfall, traditional LEO satellites dominate and persist for longer. This is demonstrated at latitudes representing major observatories where VLEO satellites are fully eclipsed 30 minutes after astronomical dusk, but higher layers continue to restrict observations. Broader literature suggests that at nightfall the lower spacecraft may be brighter if larger, but will be out of focus and rapidly transit detectors before quickly eclipsing and so the impact may be further reduced. This work develops understanding of the Starlink Gen2 network and suggests that operators deploying satellites further below the recommend 600 km altitude limit will continue to reduce the impacts on terrestrial optical astronomy; however, that benefit must be considered against the wider environmental impacts throughout the lifecycle to make informed decisions on sustainability metrics.

Keywords: Night sky brightness, Optical astronomy, Artificial satellites, Astronomical site protection, Ground-based astronomy, Space vehicles
A New Approach to Compiling Exoatmospheric Target Lists and Quantifying the Ground-based Resources Needed to Vet Them. Transiting exoplanet atmospheric characterization is currently in a golden age as dozens of exoplanet atmospheres are being studied by NASA's Hubble and James Webb Space Telescopes. This trend is expected to continue with NASA's Pandora Smallsat and Roman Space Telescope and ESA's Ariel mission (all expected to launch within this decade) and NASA's Habitable Worlds Observatory (expected to launch in the early 2040s), all of which are centered around studying the atmospheres of exoplanets. Here, we explore a new approach to constructing large-scale exoatmospheric survey lists, which combines the use of traditional transmission/emission spectroscopy figures of merit with a focus on more evenly sampling planets across a range of radii and equilibrium temperatures. After assembling a sample target list comprised of 750 transmission spectroscopy targets and 150 emission spectroscopy targets, we quantify the potential time lost to stale transit and eclipse ephemerides and find that hundreds of hours of space-based observing could be wasted given current uncertainties in orbital periods, transit epochs, and orbital eccentricities. We further estimate the amount of ground-based telescope time necessary to obtain sufficiently precise exoplanet masses and find that it exceeds 100 nights of 10 m telescope time. Based upon these findings, we provide a list of recommendations that would make community efforts for the preparation and interpretation of atmospheric characterization endeavors more effective and efficient. The strategies we recommend here can be used to support both current (e.g., Hubble Space Telescope and JWST) and future exoplanet atmosphere characterization missions (e.g., Pandora, Ariel, Roman, and the Habitable Worlds Observatory).

Keywords: Exoplanets, Surveys, Transmission spectroscopy, Radial velocity, Transit photometry
First Results from WINERED: Detection of Emission Lines from Neutral Iron and a Combined Set of Trace Species on the Dayside of WASP-189 b. Ground- and space-based observations have revealed that ultrahot Jupiters (UHJs, Teq &gt; 2200 K) typically have inverted thermal profiles, while cooler hot Jupiters have noninverted ones. This shift is theorized due to the onset of strong optical absorbers such as metal oxides (e.g., TiO, VO), metal hydrides (e.g. FeH), atomic species (e.g., Fe, Ti), and ions (e.g., H−). High-resolution spectroscopy is valuable for characterizing the thermal, chemical, and dynamical atmospheric structures due to its sensitivity to detailed spectral line shapes. The newly commissioned WINERED high-resolution spectrograph (R ∼ 68,000) on the Magellan Clay 6.5 m telescope enhances capabilities with its high throughput in the J band (1.13─1.35 μm), capturing strong spectral features from key atmospheric species. In this study, we report detection of the dayside atmosphere of the UHJ WASP-189 b at a signal-to-noise ratio S/N ∼ 10, marking the first detection of an exoplanet atmosphere in emission with WINERED. Individually, we identify strong neutral iron (Fe) emission lines at S/N = 6.3, and tentatively detect neutral magnesium (Mg) and silicon (Si) at S/N &gt; 4. Although not individually detected, we detect a combined set of trace species at S/N = 7.2, which is attributed mostly to neutral chromium (Cr) and aluminum (Al), alongside magnesium and silicon. These results help refine the understanding of key atmospheric species that influence the thermal structure of WASP-189 b and UHJs more broadly.

Keywords: High resolution spectroscopy, Exoplanet atmospheric composition , Exoplanet atmospheric structure
Revealing the Accelerating Wind in the Inner Region of Colliding-wind Binary WR 112. Colliding winds in massive binaries generate X-ray-bright shocks, synchrotron radio emission, and sometimes even dusty "pinwheel" spirals. We report the first X-ray detections of the dusty WC+O binary system WR 112 from Chandra and Swift, alongside 27 yr of Very Large Array/Australia Telescope Compact Array radio monitoring and new diffraction-limited Keck images. Because we view the nearly circular orbit almost edge-on, the colliding-wind zone alternates between heavy Wolf─Rayet wind self-absorption and near-transparent O-star wind foreground each 20 yr orbit, producing phase-locked radio and X-ray variability. This scenario leads to a prediction that the radio spectral index is flatter from a larger nonthermal contribution around the radio intensity maximum, which indeed was observed. Existing models that assume a single dust-expansion speed fail to reproduce the combined infrared (IR) geometry and radio light curve. Instead, we require an accelerating postshock flow that climbs from near-stationary to ∼1350 km s−1 in about one orbital cycle, naturally matching the IR spiral from 5″ down to within 0 .″ 1, while also fitting the phase of the radio brightening. These kinematic constraints supply critical boundary conditions for future hydrodynamic simulations, which can link hot-plasma cooling, nonthermal radio emission, X-ray spectra, and dust formation in a self-consistent framework. WR 112 thus joins WR 140, WR 104, and WR 70-16 (Apep) as a benchmark system for testing colliding-wind physics under an increasingly diverse range of orbital architectures and physical conditions.

Keywords: WC stars, High energy astrophysics, Close binary stars, Stellar winds, Wolf-Rayet stars, Circumstellar dust
JWST COMPASS: A NIRSpec G395H Transmission Spectrum of the Super-Earth GJ 357 b. We present JWST NIRSpec/G395H transmission spectroscopy observations of GJ 357 b, a warm (Teq ≍ 525 K) super-Earth (1.2 R⊕, 1.84 M⊕) orbiting a nearby M3-type star, with a median precision of 18 ppm and 27 ppm in NRS1 and NRS2, respectively. These precisions are obtained by binning the spectrum into 53 spectroscopic channels with a resolution of 60 pixels (around 0.02 μm) each. Our analysis of the transmission spectrum reveals no detectable atmospheric spectral features. By comparing the observed spectrum with 1D forward models, we rule out atmospheres with mean molecular weights (MMWs) lower than 8 g mol−1 to 3σ, as well as atmospheres with metallicities less than 300 × solar. The lack of a low-MMW primary atmosphere is consistent with a primordial H2-rich atmosphere having escaped, given the planet's ≳5 Gyr age, relatively low surface gravity (log(g) = 3.09), and its likely history of substantial incident extreme UV radiation. We conclude that GJ 357 b most likely possesses either a high-MMW secondary atmosphere, is perhaps rich in oxidized gases like CO2, or is a bare rock with no atmosphere. Upcoming scheduled JWST thermal emission observations could help distinguish between these scenarios by detecting signatures indicative of atmospheric heat redistribution or molecular absorption.

Keywords: Extrasolar rocky planets, Super Earths, Exoplanets, Transmission spectroscopy
The Unexplored Dusty Nova LMCN 2009-05a in the Large Magellanic Cloud. We present a detailed spectrophotometric study of nova LMCN 2009-05a, located in the Large Magellanic Cloud (LMC). Photometric observations reveal a dust dip in the optical light curve, classifying it as a D-class nova. Light curve analysis yields t2 and t3 decline times of approximately 46 and 80 days, respectively, placing the nova in the category of moderately fast novae. Spectroscopic observations cover multiple phases, including pre-maximum, early decline, and nebular. The spectra are initially dominated by hydrogen Balmer and Fe II lines with P-Cygni profiles, which later transition into pure emission. During the optical minimum, a discrete absorption feature was observed in the Hα and [O I] line profiles. The physical and chemical properties during the early decline and nebular phases were analyzed using the photoionization code CLOUDY. Dust temperature, mass, and grain size were estimated through spectral energy distribution fitting to the WISE data. On day 395 post-outburst, we estimate the dust temperature to be approximately 700 K. Additionally, we examined the correlation between dust condensation time (tcond) and t2 for LMC novae, finding a trend consistent with previous studies of Galactic novae.

Keywords: Photoionization, Astronomy data modeling, Optical astronomy, Light curves, Spectral line identification, Large Magellanic Cloud, Dust formation, Infrared astronomy, Spectral energy distribution, Cataclysmic variable stars, Classical novae