Sazuna/UAT_keywords huggingface dataset:
Tail Morphology of Near-Sun Comet C/2020 F3 (NEOWISE). We study the morphological changes of bright near-Sun comet C/2020 F3 (NEOWISE) using a series of multi-color wide-field images obtained in 2020 July 8–30, as the comet receded from 0.3 to 0.8 au from the Sun. Syndyne–synchrone modeling shows that the dusts that makes up the visible tail were mostly produced at and after perihelion. The images show changes of dust size distribution throughout the observations, with a gradual depletion of micron-sized particles. We discuss caveats in using the syndyne–synchrone model to study tail dynamics of comets at small perihelion distances. The r-band images consistently show a straight, non-dust tail throughout our observations that is likely to be made by neutral sodium atoms and H2O+ molecules.

Keywords: Comet tails, Long period comets, Near-sun comets, Comet dust tails
Variability Census of Legacy Catalogs. III. 8600+ New δ Scuti and γ Doradus Stars. I present the identification of over 4600 new δ Scuti and 4000 new γ Doradus stars, which represent the third phase results of a variability vetting census project in BD, HD, SAO, and PPM catalogs. Across project phases I–III (scanning 468,862 catalog objects), I have identified over 9690 δ Scuti, 7680 γ Doradus, 2600+ Maia variables, 1030+ eclipsing binaries, 20+ RR Lyrae stars, 180+ heartbeat candidates, 9800+ rotating variables (including subtypes of 370+ ELL, 800+ ACV, 100+ SXARI, and hundreds of solar-like oscillators), and several other types as new variables. Notably, more than 120 eclipsing binary systems have been identified with pulsating primary components of either DSCT or GDOR type, while 24 more binaries feature overlapping Maia-type pulsation. Moreover, over 2200 of these variables exhibit hybrid δ Sct-γ Dor pulsations. *Dedicated to my wife Jingyun Zhang.

Keywords: Eclipsing binary stars, Gamma Doradus variable stars, Delta Scuti variable stars, Pulsating variable stars
An Analysis of Blue Straggler Stars in Open Clusters. The presence of blue straggler stars (BSSs) in open clusters (OCs) presents an opportunity to study star formation and cluster dynamics. Our paper analyzes several properties of BSSs across 161 OCs of different ages, metallicities, and sizes. Specifically, we examine the impact of cluster age and metallicity on the number of BSSs as well as the spatial distribution of BSSs within each cluster. We report a positive correlation between the age of the cluster and the number of BSSs present. This investigation into BSSs provides valuable insights into their formation as well as the dynamics and interactions within open clusters.

Keywords: Stellar astronomy, Blue straggler stars, Open star clusters
Using the COSMIC Population Synthesis Code to Investigate How Metallicity Affects the Rates of Interacting Binaries. We use COSMIC, a galaxy population synthesis code, to investigate how metallicity affects the rate of formation of massive stars with a closely orbiting compact object companion. Metallicity—a crucial component to stellar evolution and binary system formation—can affect how and when these systems form. We present the formation time of these systems at different metallicities, and the anti-correlation the rates have with metallicity. In particular, these systems occur about 10 times more frequently at metallicities between Z = 2 × 10‑4 and 2 × 10‑3, compared to those between Z = 2 × 10‑3 and 2 × 10‑2. This work serves as a prerequisite to predicting global rates of these systems as a function of redshift, ultimately giving crucial insight into our understanding of the progenitors of long gamma-ray bursts and their evolution over cosmic time.

Keywords: Gamma-ray astronomy, Metallicity, Astronomical simulations, Compact binary stars
Determination of Surface Abundances for HD 129174 (π <SUP>1</SUP> Boo). The synthesis of the Hg II line at 3983.93 Å, using published hyperfine structure and nuclear shifts, confirms a large overabundance of mercury in HD 129174, about +6.18 dex, which is actually slightly larger than the excess derived in earlier studies. The synthesis of 17 other lines close to the Hg II line and in the spectral range 4400–4500 Å yields abundances for 9 elements. Helium and iron are found to be deficient by ‑1.12 and ‑0.097 dex. Magnesium, scandium, titanium, chromium are moderately enhanced by respectively +0.30 dex (Mg) and +1.0 dex (Sc, Ti and Cr). Yttrium and zirconium are very overabundant by +4.00, +2.48 dex respectively.

Keywords: Mercury-manganese stars, Chemically peculiar stars
The Escape Probability of Photons Emitted in a Spherical Homogeneous Shell. We present a general expression for calculating the escape probability of photons from a dusty homogeneous spherical shell.

Keywords: Dust shells, Radiative transfer equation, Circumstellar dust, Radiative transfer
Jet-induced Enhancement of the Nova Rate in M87. We argue that the Bondi accretion mechanism has the potential to enhance classical nova production near the M87 jet. According to our estimates, the jet's influence can increase the nova rate in its vicinity by up to a factor of two over the background rate by triggering explosions on single white dwarfs. This result may offer a straightforward explanation for the recently observed excess of novae near the M87 jet.

Keywords: Giant elliptical galaxies, Galaxy jets, Novae
Multicolor Photometry of the Be/X-Ray Pulsar IGR J06074+2205. B, V, and R observations of the Be/X-ray pulsar IGR J06074+2205 were taken in 2023–2024 covering times of expected X-ray outbursts. However, no coinciding optical outbursts were found. The overall optical brightness of the system faded in all 3 filters, with the least decline being in B and the greatest in R. This suggests that a cool disk was contributing less light to the system.

Keywords: Be stars, X-ray binary stars
Hidden Companions to Intermediate-mass Stars. XXI. Discovery of a 0.5 M <SUB>⊙</SUB>, 1.5 au Companion to Sadachbia = Gamma Aquarii. Sadachbia = Gamma Aquarii is a nearby A0V star that was suspected to be a spectroscopic binary. Here we report on the direct detection of a companion with a K band flux ratio of 1.2% at a projected separation of 38.2 mas based on a VLTI/GRAVITY near-infrared interferometric observation. The implied mass and separation of the companion are 0.46 M ⊙ and 1.5 au based on the Gaia DR3 distance (or 0.55 M ⊙ and 1.9 au if the discrepant Hipparcos distance is used instead). The companion explains the X-ray emission of γ Aqr and the orbital motion with a period of about one year likely explains the discrepant Gaia and Hipparcos parallaxes. Further observations are necessary to measure the binary semimajor axis but it is likely that the system will undergo common envelope evolution. The primary is partially resolved with an angular diameter of 0.52 mas. *Based on observations collected at the European Southern Observatory, Chile, Program ID 113.26GM.001.

Keywords: Optical interferometry, Multiple stars, A stars
Galaxy Zoo: Morphologies Based on UKIDSS NIR Imaging for 71,052 Galaxies. We present morphological classifications based on Galaxy Zoo analysis of 71,052 galaxies with imaging from the United Kingdom Infrared Telescope Infrared Deep Sky Survey (UKIDSS). Galaxies were selected out of the Galaxy Zoo 2 (GZ2) sample, so also have gri imaging from the Sloan Digital Sky Survey. An identical classification tree, and vote weighting/aggregation was applied to both UKIDSS and GZ2 classifications enabling direct comparisons. With this Research Note we provide a public release of the GZ:UKIDSS morphologies and discuss some initial comparisons with GZ2.

Keywords: Sky surveys, Galaxy classification systems, Galaxies
The Coronal Lines of the High-excitation, Fe II-type Nova V2467 Cygni. Optical and infrared spectra are presented for the nova V2467 Cygni from the period of its maximum excitation. The spectra indicate exceptionally high excitation for a Fe II-type nova, exhibiting [Si X] 1.4305 μm and several emission lines that we associate with C VI. Along with numerous coronal features, V2467 Cygni also displayed low-excitation nebular lines. A CLOUDY analysis indicates a temperature of 5.5 × 105 for its exciting source, a very heterogeneous emission line region, and an ejected mass ≥1.5 × 10‑4 L ☉.

Keywords: Classical novae
Illumination of a Planet by a Black Hole Moon as a Technological Signature. I show that Hawking radiation from a mini black hole with a mass of ∼1011 g in a low orbit around an otherwise frozen rogue planet, can supply the energy needs of a civilization on the surface of the planet. Maintaining this furnace for more than a few years requires a modest accretion rate of ∼2 kg s‑1. The associated technosignature is detectable as a gamma-ray source occulted by a warm planet every 1–2 hr, with no stellar-mass companion.

Keywords: Hawking radiation, Black hole physics
Identifying Uncertainties in Stellar Evolution Models Using the Open Cluster M67. Stellar age estimates are often calculated by interpolating a star's properties in a grid of models. However, different model grids will give different ages for the same star. We used the open cluster M67 to compare four different model grids: DSEP, GARSTEC, MIST, and YREC (10.5281/zenodo.12775242). Across &lt;!--AQ1--&gt;all model grids, age estimates for main sequence stars were consistently higher than the accepted age of M67, while age estimates for red giant stars were lower. We compared model-generated age and mass values to external constraints as an additional test of the reliability of each model grid. For stars near solar age and metallicity, we recommend using the DSEP model grid to estimate the ages of main sequence stars and the GARSTEC model grid for red giant stars.

Keywords: Open star clusters, Stellar evolutionary models
A Candidate Dark Matter Deficient Dwarf Galaxy in the Fornax Cluster Identified through Overluminous Star Clusters. Two low surface brightness (LSB) dwarf galaxies were identified recently as having little or no dark matter (DM), provoking widespread interest in their formation histories. These galaxies also host populous systems of star clusters that are on average larger and more luminous than typical globular clusters (GCs). We report an initial attempt to identify new candidate DM-deficient dwarfs via their unusual GC systems. Using a large catalog of LSB galaxies from the Dark Energy Survey, we inspect their Dark Energy Camera Legacy Survey (DECaLS) imaging and identify FCC 224 as a candidate found on the outskirts of the Fornax cluster. We analyze the GC system using DECaLS and archival Hubble Space Telescope WFPC2 imaging, and find an apparent population of overluminous GCs. More detailed follow-up of FCC 224 is in progress.

Keywords: Globular star clusters, Galaxy dark matter halos, Galaxy formation, Dwarf galaxies, Dwarf elliptical galaxies, Star clusters, Extragalactic astronomy, Dark matter, Galaxies, Low surface brightness galaxies
Determination of the Abundance of Mercury from the Hg II Line at 5677.10 Å in Late B-type Stars. V. HD 174933 (112 Her). The weak line of Hg II located at 5677.10 Å is used to measure the mercury abundance in the HgMn star HD 174933 (112 Her). This line is detected at 3σ above the noise in the adjacent continuum. The synthesis of this line, confirms a large overabundance of mercury, about +4.54 dex, which is less than the excess derived from the 3983.93 Å line in earlier studies. The synthesis of lines in five spectral regions yields estimates of the abundance deficienciess/excesses for twelve other elements. Helium, carbon and magnesium are very depleted, titanium, manganese and iron are moderately overabundant. Strontium, yttrium, zirconium and barium have solar abundances upper limits. Phosphorus, gallium and mercury are very overabundant. The abundance pattern of 112 Her differs from that of other HgMn stars as already stressed in previous studies.

Keywords: Mercury-manganese stars, Chemically peculiar stars
A Comment on the Solar Activity Level in 1744 by Diego de Torres Villarroel. Solar activity in recent centuries is crucial for astrophysics and geophysics, with historical sunspot records providing key insights, particularly for the 17th and 18th centuries. However, certain periods, such as around 1744, are still poorly understood. This note explores a qualitative commentary on solar activity from that time by Diego de Torres Villarroel, a notable Spanish writer. In his pamphlet on the great comet of 1744, Villarroel observed that the Sun appeared unusually clear, with fewer sunspots and faculae than usual, indicating low solar activity. These observations are consistent with the known solar minimum between cycles ‑1 and 0 around 1744. While Villarroel's remarks only offer qualitative confirmation of existing knowledge, they are important for filling in gaps in historical records of solar activity and should be preserved for future research.

Keywords: Solar cycle
A Rare Cepheid-hosting Open Cluster Triad in Sagittarius. The following Galactic star clusters may constitute a rare Cepheid hosting triad in Sagittarius: M25, NGC 6716, and Collinder 394. The open clusters have comparable ages (τ ≃ 80 Myr) and nearly aligned main-sequences and turnoffs after accounting for differential extinction (A  G , ). Gaia DR3 astrometry confirms an association between the three clusters, and importantly, the classical Cepheid U Sgr is a member (P ≃ 6.ͩ75, τ ≃ 80 Myr), while DR3 data indicate that the classical Cepheid BB Sgr (P ≃ 6.ͩ64, τ ≃ 80 Myr) could possibly be an escaped member traversing the background field.

Keywords: Open star clusters, Cepheid variable stars
Hidden Companions to Intermediate-mass Stars. XXII. Inferring a 0.43M <SUB>⊙</SUB>, 1.65 au Companion in the Astrometric Binary within the Triple System Lambda Muscae. Lambda Muscae is a nearby A-type star reported as a P = 474 days astrometric binary in Gaia DR3 (and previously in Hipparcos) and which also has a 0.16M ⊙ M dwarf companion at a projected separation 6.4 au discovered by VLT/SPHERE. Based on a K band flux ratio upper limit of 1% from a VLTI/GRAVITY interferometric observation, we estimate a primary mass M  Aa  = 2.28M ⊙ and infer that the closer companion is a M  Ab  = 0.43M ⊙ star (almost certainly an M dwarf) orbiting at a = 1.65 au. The triple system might be dynamically interesting given the low hierarchy and the ratio of angular momenta of the inner and outer orbits of about one. *Based on observations collected at the European Southern Observatory, Chile, Program ID 111.24UP.001.

Keywords: Optical interferometry, Multiple stars, Astrometric binary stars, A stars
Sizes and Stellar Masses of the Little Red Dots Imply Immense Stellar Densities. The "Little Red Dots" (LRDs) are red and compact galaxies detected in JWST deep fields, mainly in the redshift range z = 4–8. Given their compactness and the inferred stellar masses in the hypothesis that LRDs are starburst galaxies, the implied stellar densities are immense. This Research Note uses an extensive catalog of LRDs from the PRIMER and the COSMOS-Web surveys to investigate these densities. We find a median (upper limit) on the effective radius of 80 pc, which leads to median (lower limit) values of the core density of ∼104 M ⊙ pc‑3, and individual densities as high as ∼108 M ⊙ pc‑3, which is ∼10 times higher than the density necessary for runaway collisions to take place. For ∼35% of the LRDs investigated, the lower limits are higher than the highest stellar densities observed in any system in any redshift range.

Keywords: Surveys, Early universe, Galaxy evolution, Galaxies
On the Dynamical Erasure of Initial Conditions in Multi-planetary Systems. Do sub-Neptunes assemble close to where we see them or do they form full-fledged farther away from their host star then migrate inwards? We explore this question using the distribution of measured orbital periods, one of the most fundamental observable parameters. Under disk-induced migration, planet occurrence rate is expected to decrease toward shorter orbital periods. Presently, the observed sub-Neptune period distribution is flat in log period, between 10 and 300 days. We show, using N-body integration, how post-disk dynamical instabilities and mergers in multi-planetary systems erase the initial conditions of migration emplaced in period distributions over 10 s to 100 Myr timescale, in rough agreement with an observational hint of the abundance of resonant pairs for systems younger than 100 Myr which drops dramatically for more evolved systems. We comment on caveats and future work.

Keywords: Exoplanet dynamics, Exoplanet astronomy, Exoplanet formation
Gas Dynamics in the Herbig Ae Star HD 163296 in 2024. We observed the Herbig Ae star HD 163296 over 9 nights in 2024. On 4 of the nights, the He I line at 1.083 μm exhibited a profile rarely seen in the star. Rather than the typical P Cygni profile indicating a net gas outflow, the profile consisted of a deep absorption line with weak emission peaks on either side. These seem to be consistent with either an outflowing bipolar jet, a circular ring of gas orbiting close to the star, and/or accretion columns connecting the inner disk to the star. Given the history of the ejection of Herbi-Haro object in the star's bipolar jets, these observations should coincide with the very beginning of the ejection event. Coordinated observations with multiple observing techniques over the next decade are warranted.

Keywords: Protoplanetary disks, Circumstellar gas
Multi-color Photometry of Near-Earth Asteroid (415029) 2011 UL21. BVR photometric series of observations of potentially hazardous asteroid (415029) 2011 UL21 were obtained at the Astronomical Station of Vidojevica around its close approach to the Earth on 2018 July 1. From these observations, the color indices V ‑ R = 0.48 ± 0.07 and B ‑ V = 0.89 ± 0.06 were determined, suggesting R- or S-type taxonomic classification of the object. The observed small lightcurve amplitude suggests a nearly spherical shape of the asteroid.

Keywords: Near-Earth objects, Asteroids, Small Solar System bodies
Excluding Primordial Black Holes as Dark Matter Based on Solar System Ephemeris. Current cosmological constraints allow primordial black holes to constitute dark matter in the mass range of 1018–1022 g. I show that a major portion of this logarithmic window can be ruled-out based on the solar system ephemeris, given that the external mass enclosed within 50 au from the Sun did not change by more than ∼5 × 10‑14 M ⊙ yr‑1 in recent decades.

Keywords: Dark matter, Black holes, Solar system
A False Positive Transit Candidate for EPIC 211101996 from K2 and TESS Data Identified as Background Eclipsing Binary Gaia DR3 66767847894609792. Transiting planets around young stars are hard to find due to the enhanced stellar activity. Only a few transiting planets have been detected around stars younger than 100 Myr. We initially detected a transit-like signal in the K2 light curve of a very cool M dwarf star (EPIC 211101996) in the Pleiades open cluster, with an estimated age of about 100 Myr. Our detailed analysis of the per-pixel light curves, detrending with the Wōtan software and transit search with the Transit Least Squares algorithm showed that the source of the signal is a contaminant source (Gaia DR3 66767847894609792) 20″ west of the target. The V-like shape of its phase-folded light curve and eclipse depth of ∼15% suggest that it is a grazing eclipsing binary. The contaminant has hitherto been listed as a single star, which we now identify as an eclipsing stellar binary with a period of about 6 days.

Keywords: Exoplanets, Light curves, Space observatories, Eclipsing binary stars, Exoplanet detection methods
New Transient Co-orbital Asteroids of Venus. Venus has no known natural satellites but has 5 known co-orbitals. These are objects trapped in a 1:1 mean-motion resonance with Venus. Co-orbital configurations include retrograde satellite orbits (RS), tadpole orbits (T) around the Lagrangian equilibrium points L4 or L5, and horseshoe orbits around both L4 and L5 (H). At high eccentricity or inclination, co-orbital configurations may also involve compounds of T and RS (T-RS, T-RS-T), H and RS (H-RS) orbits, or transitions between different co-orbital modes. Here we identify asteroids in 2 RS, 1 L4-tadpole, 2 H-RS, and 2 T-RS orbits, as well as 8 additional asteroids in possible temporary co-orbital status. Although the majority of these objects do not yet have well-characterized orbits, 2020 CL1, and 2020 SB do and are very likely to be new co-orbital asteroids. With the new candidates, Venus would have a population of 20 co-orbital asteroids, comparable to those of Mars and Earth.

Keywords: Near-Earth objects, Small Solar System bodies, Asteroids, Lagrangian points, Venus, Celestial mechanics, Trojan asteroids, Three-body problem, Close encounters
LIGO-Virgo-KAGRA Limit on Relativistic Interstellar Objects near Earth. Relativistic interstellar objects (RISOs) are not constrained by astronomical sky surveys because they are smeared in sky images and at best appear in one frame. Here, I show that irrespective of their nature, RISOs more massive than ∼1014 g would have been detected by the LIGO-Virgo-KAGRA collaboration through their tidal gravitational signal at a frequency of f ∼ 50 Hz within a distance comparable to the Earth radius. This constrains the passage of relativistic primordial black holes or other exotic objects at the local mass density of dark matter near Earth over the past decade.

Keywords: Gravitational waves, Dark matter, Interstellar dynamics
RETRACTED: Exoplanet Harmony: Confirming Kepler's Third Law with Kepler and TESS Discoveries. We investigate whether the orbital periods of exoplanets discovered by the Kepler and TESS missions adhere to Kepler's Third Law, akin to the planets in our solar system. Using data obtained from the NASA Exoplanet Archive (DOI:10.26133/NEA12) on 2024 June 24, we analyzed 2659 Kepler observations and 415 TESS observations. Our results demonstrate that the exoplanets observed by both Kepler and TESS missions follow Kepler's law, with deviations that are within the expected range of observational uncertainties. This confirms that Kepler's Third Law holds true for exoplanets beyond our solar system.

Keywords: Exoplanet catalogs
mardigras: A Visualization Tool of Theoretical Mass–Radius Relations in the Context of Planetary Science. Over the past two decades, mass–radius relations have become a crucial tool for inferring the bulk composition of exoplanets using only their measured masses and radii. These relations, often referred to as isocomposition curves, are derived from interior structure models by calculating the theoretical radius as a function of mass for a given fixed planetary composition. Each mass–radius curve can be influenced by a variety of parameters, such as planetary composition, age, and equilibrium temperature. Navigating this parameter space can be cumbersome, particularly when models or their results are not open-source. To address this challenge, I have developed MAss–Radius DIaGRAm with Sliders, a visualization tool that enables simple, fast, and interactive exploration of the parameter space that governs mass–radius relations for any given model.

Keywords: Extrasolar rocky planets, Ocean planets, Exoplanet catalogs, Exoplanets, Exoplanet evolution, Extrasolar gaseous planets, Planetary interior, Planetary structure