Sazuna/UAT_keywords huggingface dataset:
Hidden Companions to Intermediate-mass Stars. XIX. Spin–Orbit Misalignment and a 0.26M <SUB>⊙</SUB>, 1.8 au Companion in the Astrometric Binary Gamma Trianguli Australis. Gamma Trianguli Australis is a nearby A-type star that was reported to be a 488 days astrometric binary in Gaia DR3. Here we report on a VLTI/GRAVITY observation of γ TrA in which we did not detect the companion down to a K band flux ratio of 0.5%. From the isochrone mass M  A  = 3.04M ⊙ of the subgiant primary, this implies a semimajor axis a orb = 1.8 au and that the companion is a M  B  = 0.26M ⊙ M dwarf. The primary disk is partially resolved with an angular diameter θ 1 ≈ 1 mas ↔ 13.0R ⊙. The differential visibility phases across the Brγ absorption line allowed us to measure the longitude of the ascending node of the primary's rotational plane Ωrot = 212° ± 3°. This implies a spin–orbit misalignment of at least 27° ± 3° based on the Gaia astrometric solution. *Based on observations collected at the European Southern Observatory, Chile, Program ID 111.24UP.001.

Keywords: Optical interferometry, Stellar rotation, Astrometric binary stars, A stars
How Reliable are Rotation Period Determinations from TESS Data?. Gyrochronology is the empirical relation between rotation and age. NASA's Transiting Exoplanet Survey Satellite (TESS), Kepler, and K2 missions have observed thousands of wide main sequence binaries. Since components of a binary are coeval, their rotation periods should be consistent with gyrochronology models. However, the usefulness of gyrochronology depends upon reliable rotation periods. We explore the reliability of rotation period determinations for a sample of wide binary components from the TESS cycle 3. Wide binaries with the most reliable rotation period determinations provide a strong basis for testing whether the gyrochronology empirical relation derived from open clusters is also valid for field stars.

Keywords: Stellar rotation, Stellar physics, Stellar ages
Why the Laplace Resonant Angle is So Special. We analyze adjacent local pairs of mean-motion resonances (MMRs) between three orbiting bodies designed to produce a Laplace resonant phase angle φ L or one of its multiples N φ L, where integer N ≥ 2. This assumption yields a concrete pattern of Laplace resonances, very few of which (with angles φ L and 2φ L) have been observed in actual (extra)solar subsystems. All other MMRs face issues of proximity or remoteness of the orbits (they are too close or too far apart). We highlight one as yet unobservable MMR in each N-sequence for which these issues appear to be less acute.

Keywords: Exoplanet dynamics, Orbital resonances, Exoplanets
The Spectral ANalog of Dwarfs (SAND): New Model Atmospheres with Varying Chemistry for Galactic Archaeology with Ultracool Dwarfs. The atmospheres of Ultracool Dwarfs (UCDs) are dominated by molecular chemistry, which makes their spectra and photometry particularly sensitive to elemental abundances. With lifespans in excess of the age of the universe, UCDs serve as chemical tracers in every component of the Milky Way. In this study, we present the Spectral ANalog of Dwarfs (SAND) grid of low-temperature model atmospheres that span T eff from 700 to 4000 K, $\mathrm{log}(g)$ from 4.0 to 6.0, [Fe/H] from ‑2.4 to +0.3, and a range of [α/Fe] that matches the Galactic distribution inferred from earlier spectroscopic surveys. The SAND grid primarily aims to model the spectra of brown dwarfs in the halo and thick disk of the Milky Way, and metal-poor UCDs in globular clusters.

Keywords: Galactic archaeology, Brown dwarfs, Stellar atmospheres
Deep HST/UVIS Imaging of the Candidate Dark Galaxy CDG-1. CDG-1 is a tight grouping of four likely globular clusters in the Perseus cluster, and a candidate dark galaxy with little or no diffuse light. Here we provide new constraints on the luminosity of any underlying stellar emission, using Hubble Space Telescope/UVIS F200LP imaging. No diffuse emission is detected, with a 2σ upper limit of F200LP &gt; 28.1 mag arcsec‑2 on the 5″ scale of CDG-1. This surface brightness limit corresponds to a 2σ lower limit of &gt;0.5 for the fraction of the total luminosity that is in the form of globular clusters. The most likely alternative, although improbable, is that CDG-1 is a chance grouping of four globular clusters in the halo of the Perseus galaxy IC 312.

Keywords: Globular star clusters, Dwarf galaxies
Determination of the Abundance of Mercury from the Hg II Line at 5677.10 Å in Late B-type Stars: Paper I—HD 35548 and HD 89822. The weak line of Hg II located at 5677.10 Å is used to measure the mercury abundance in two mercury rich stars, HD 35548 and HD 89822. The synthesis of this line, using the current atomic parameters available in NIST, confirms that mercury is very abundant in both stars. The abundance derived from this line is in very good agreement with the abundance derived from the commonly used line at 3983.93 Å for HD 35548 but it is smaller for HD 89822.

Keywords: Mercury-manganese stars, Chemically peculiar stars
Ultracool Dwarf Absolute Magnitude Versus Spectral Type Relations for Euclid and Roman Near-infrared Filters. We synthesize Euclid Near Infrared Spectrometer and Photometer photometry for the Y  E  J  E  H  E  filters and Roman Wide Field Instrument photometry for the F106, F129, F146, F158, F184 and F213 filters using SpeX prism spectra and parallaxes of 688 field-age and 151 young (≲200 Myr) ultracool dwarfs (spectral types M6–T9). For the above filters, we derive empirical absolute magnitude-spectral type polynomial relations that enable the calculation of photometric distances for ultracool dwarfs to be observed with Euclid and Roman, in the absence of parallax measurements. The synthesized photometry can also be used to generate color–color figures to distinguish high-redshift galaxies from brown dwarf interlopers.

Keywords: Stellar spectral types, Absolute magnitude, Brown dwarfs, Photometry
Localizing Stellar Activity on Low-mass Stars with the Transiting Exoplanet Survey Satellite. Magnetic reconnection is the underlying cause of stellar flares which are linked to regions of high magnetic activity, like star spots. To understand trends in stellar activity, we need to study how it is heightened by rapid rotation and deep convection in young low-mass stars. We analyze light curves of such stars observed by the Transiting Exoplanet Survey Satellite to investigate trends in flare timing with starspot modulation signals. Trends in flare properties and spot modulation can provide a means to "localize" which face of a star flares more frequently and better understand their association with active regions. We present an analysis of light curves from M and K dwarfs with no companions from five nearby and young moving groups spanning ages ∼20–150 Myr. We discuss a technique to analyze the distribution of flares and star spots and describe our results, which reveal a tentative correlation.

Keywords: Starspots, Light curves, K stars, M stars, Stellar astronomy, Stellar flares, Low mass stars, Optical flares
M-Dwarf Flare Candidates Simultaneously Observed by K2 and TESS. We present results of a study on the identification of M-dwarf flares using K2 and TESS data. Our sample includes objects observed simultaneously by these two missions, so that we can also compare how flares are identified in the two sets of data. We implement two open-source Python packages, Lightkurve and PyVAN, to work in unison to easily access the data and determine variability in the light curves of 39 M-dwarfs. We identified 13 flare detections in the TESS data while K2 did not provide any reliable detections of flares. We describe the shortcomings of the K2 data that prevented these flares from being identified.

Keywords: M dwarf stars, Space telescopes, Stellar flares
Discovery of Jupiter Family Comet 2011 UG<SUB>104</SUB> Through AI Enhanced Citizen Science. We report the discovery of cometary activity from minor planet 2011 UG104, which we classify as a Jupiter Family Comet (JFC). This discovery was aided by our Artificial Intelligence (AI) classification system: TailNet. JFC's, short-period comets with eccentric Jupiter-crossing orbits, originate from the Kuiper Belt and thus give us unique insight into the composition and distribution of volatiles in the outer solar system, past and present. Our AI assistant TailNet first classified 2011 UG104 as active, which was affirmed by Citizen Scientists on our NASA Partner Program Active Asteroids. Through further archival image searches our science team found evidence of activity on 2011 UG104 on three separate observations from 2021 February to 2021 April (81.°8 &lt; f &lt; 95.°0).

Keywords: Comet tails, Convolutional neural networks, Asteroids, Comae
A Python Project Template for Healthy Scientific Software. The creation of "healthy" scientific software is vital for its successful long-term adoption in scientific research. Here healthy code is defined to mean software that is usable, maintainable, and proffers consistently reproducible results. Incorporating tooling and practices to achieve these goals often leads to short-term, yet significant, overhead for new projects. We introduce the LINCC Frameworks Python Project Template, a configurable code template designed for scientific software projects that greatly simplifies adopting best practices by automating the setup and configuration of important tools locally and via a suite of GitHub workflows. Notably, the template does not include any application-specific code, thereby enabling users to focus on their scientific code rather than building or maintaining code infrastructure.

Keywords: Open source software
An Additional Note to "A New Insight into the Linear Theory of Magnetoacoustic Waves in the Homogeneous Flux Tubes with an Abrupt Boundary". This is to address the criticism expressed in the article (Goedbloed &amp; Poedts 2024) referred to as GP[24] about the work (Yelagandula 2023) referred to as Y[23]. It will be shown that the dispersion relation obtained in Y[23] is indeed correct within the framework of the ZSER model discussed in Y[23] despite the correct criticism of GP[24] about the electrodynamic boundary condition.

Keywords: Solar coronal loops
Recovering Data of an Observation of the Leonids in 1869 from the Lisbon Geophysical Observatory (Portugal). The Leonid meteor shower is renowned for its scientific and public interest. In a search for meteorological data from Portuguese stations, records on an observation of the Leonids in 1869 from the Lisbon Geophysical Observatory "Infante Dom Luiz" were found. Given their potential value, a digital version with metadata is provided in the present note (the recovered data are available on doi:10.5281/zenodo.11221019). The observation took place from 9 PM on 1869 November 13 to 6 AM on November 14, local time in Lisbon, with mostly clear skies and 4–5 observers covering completely the sky. They recorded 1980 meteors, noting Zodiacal Light visibility and detailing meteor counts every five minutes.

Keywords: Meteors
Consolidated Rotation Measure Catalog Update. We identified discrepancies between the rotation measure (RM) catalogs by Clegg et al. and Minter &amp; Spangler and their corresponding rows in the Van Eck et al. consolidated catalog. The discrepancies, in the case of Minter &amp; Spangler, are caused by the improper coordinate conversions between J2000 and B1950 Equatorial coordinate systems used between the catalogs. The discrepancies associated with Clegg et al. are due to differences in the number of significant figures reported between the original and consolidated catalogs, which result in overlapping points in the consolidated catalog. These errors affect studies that rely on the accuracy of the coordinate data. After proper unit conversions, we found that coordinate values differed by up to 1° between the Minter &amp; Spangler and consolidated catalogs. Employing a combination of manual data extraction and automated coordinate conversion tools, we corrected and updated those RM coordinate values to align with the standardized format used in the Van Eck et al. consolidated catalog.

Keywords: Radio source catalogs, Interstellar magnetic fields, Interstellar medium, Radio astronomy, Catalogs
Background Contamination of the Project Hephaistos Dyson Spheres Candidates. Project Hephaistos recently identified seven M-dwarfs as possible Dyson Spheres (DS) candidates. We have cross-matched three of these candidates (A, B and G) with radio sources detected in various all-sky surveys. The radio sources are offset from the Gaia stellar positions by ∼4.9, ∼0.4 and ∼5.″0 for candidates A, B, and G respectively. We propose that Dust obscured galaxies (DOGs) lying close to the line-of-sight of these M-dwarf stars significantly contribute to the measured WISE mid-IR flux densities in the WISE W3 and W4 wave bands. These three stars have therefore been misidentified as DS candidates. We also note that with an areal sky density of 9 × 10‑6 per square arcsecond, Hot DOGs can probably account for the contamination of all 7 DS candidates drawn from an original sample of 5 million stars.

Keywords: Search for extraterrestrial intelligence, Technosignatures, Infrared sources, Extragalactic radio sources
Direct Imaging Detection of the Protoplanet AB Aur b at Wavelengths Covering Paβ. Recently, Biddle et al. claimed a non-detection of the protoplanet AB Aurigae b in Keck/NIRC2 Paβ imaging. I reprocess these newly public data and compare them to data from the extreme AO platform (SCExAO/CHARIS) used to discover AB Aur b. AB Aur b is decisively imaged with SCExAO/CHARIS at wavelengths covering Paβ. The Biddle et al. non detection of AB Aur b results from a far poorer image quality that is non competitive with SCExAO/CHARIS. Their contrast limits and thus constraints on accretion are overestimated due to an inaccurate AB Aur b source model. Irrespective of image quality, single-band Paβ imaging is ill suited to conclusively identify accretion onto AB Aur b. Instead, high-resolution Hα spectroscopy may provide accretion signatures. Aside from PDS 70, AB Aurigae remains the system with the strongest evidence for having a directly imaged protoplanet.

Keywords: Planet formation, Exoplanet formation, Adaptive optics, Exoplanets
The Abundance of Chlorine in the Atmosphere of HD 87240. High resolution high signal-to-noise UVES spectra of the late B-type chemically peculiar star, HD 87240, a member of the NGC 3114 open cluster, have been synthesized to measure the abundance of chlorine, an element which is rarely found in late B-type stars. Sixteen lines of Cl II are found and the mean chlorine overabundance is about 2.1 dex higher than the solar abundance, which is slightly lower than the chlorine excess in HR 1094, another chlorine-rich late B-type star.

Keywords: Chemically peculiar stars
The Distribution of Satellites in the TNG100 Simulation based on Time Spent in Halo. An important test of the Λ Cold Dark Matter model is the degree to which galaxy dark matter halos follow the predicted, characteristic density profile. In this Note, we explore the use of satellite galaxies as luminous tracers of halo mass density profiles as a function of the time since they joined the halos. We perform this investigation in the TNG100 simulation, where we can obtain precise locations of satellite galaxies and dark matter particles. We find that, by adopting a more accurate definition of joining redshift compared to a previous investigation, the oldest satellites are better, but not perfect tracers of the dark matter distribution.

Keywords: Galaxy dark matter halos, Dark matter distribution, Companion galaxies
Gaia DR3 Data of Very Young Open Cluster NGC 6530: Distance and Evolutionary Stage of Selected Stars. Gaia EDR3 and Gaia DR3 data of selected stars in the very young (1.5 million years old) open cluster NGC 6530 are presented. All the selected stars have very accurate Gaia DR3 distances. Most of the selected stars are very young B stars and several of them are young stellar objects. From the analysis of selected stars, the distance to NGC 6530 is found to be 1318 pc. The two very red stars VAJ 304 and 338 have little bit less proper motion than other members of the NGC 6530 and their Mv values are found to be ‑3.57 and ‑3.68 respectively. They are much brighter than K5 III RGB stars and less luminous than massive K5 red supergiants. It is likely VAJ 304 and VAJ 338 are not members of NGC 6530 they may be field K5 type AGB or post-AGB stars. Further study of these two stars is needed.

Keywords: Open star clusters
Deep HST Imaging Favors the Bulgeless Edge-on Galaxy Explanation for the Hypothetical Stellar Wake Created by a Runaway Supermassive Black Hole. A long linear structure recently discovered could be the stellar wake produced by the passage of a runaway supermassive black hole (SMBH) or, alternatively, a bulgeless edge-on galaxy. We report on new very deep Hubble Space Telescope imaging that seems to be in tension with the SMBH runaway scenario but is consistent with the bulgeless edge-on galaxy scenario. The new observations were aimed at detecting two key features expected in the SMBH scenario, namely, the bow shock formed where the SMBH meets the surrounding medium, and a counter stellar wake created by another binary SMBH hypothesized as part of the ejection mechanism. Neither of these two features appears to be present in the new images, as would be expected in the edge-on galaxy scenario.

Keywords: Black holes, Disk galaxies
ASKAP-EMU Radio Emission from Type Ic Supernova SN1996aq in NGC 5584. We report the Australian Square Kilometre Array Pathfinder Evolutionary Map of the Universe survey detection of radio continuum emission from SN1996aq, a Type Ic supernova within the nearby face-on spiral galaxy NGC 5584. Analysis at multiple radio frequencies reveals radio emission coincident with SN1996aq. We find a flatter radio spectral index compared to the 2009 observations, indicating rapid evolution of SN1996aq. Conversely, no radio emission is observed from NGC 5584's other known supernova, SN2007af. Furthermore, we identified two other significant radio continuum regions with properties consistent with H II regions.

Keywords: Supernova remnants, Radio continuum emission, Spectral index, H II regions, Supernovae
Progenitor Stars Calculated with Small Reaction Networks should not be Used as Initial Conditions for Core Collapse. Core collapse initial conditions are a bottleneck in understanding the explosion mechanism(s) of massive stars. Stellar evolution codes struggle after carbon burning, and either stop or adopt numerical simplifications missing crucial physics. The use of small nuclear reaction networks (NRN) that account for energy production but bypass weak reactions is typical, but insufficient to study the dynamics of the collapse. We advise against the use of progenitors computed with small NRN in expensive multidimensional simulations of core collapse, bounce, (jet formation), and explosion.

Keywords: Stellar rotation, Massive stars, Gamma-ray bursts, Supernovae
No Significant Redshift Evolution in the Intrinsic Scatter of the M <SUB>•</SUB>–M <SUB>⋆</SUB> Relation for Overmassive Black Holes. In the local Universe, the ratio between the mass of a central black hole and the stellar mass of its host galaxy is ∼0.1%. Recently, JWST discovered numerous galaxies at z &gt; 4 that seem to deviate from the local relation, with black holes overmassive by 10–100 times. Similar galaxies were also discovered at cosmic noon. The intrinsic scatter in the relation describes how much the evolutionary histories of the single galaxies deviate from the mean evolutionary pattern of their parent data set. This Research Note examines whether a cosmic evolution of the intrinsic scatter can be detected by assessing its value for data sets in various redshift ranges. Using data from the local Universe (z &lt; 0.055), low (0.4 ≤ z ≤ 0.9), intermediate (0.9 ≤ z ≤ 4), and high (z &gt; 4) redshift, we conclude that there is no statistically significant redshift evolution of the intrinsic scatter.

Keywords: Surveys, Supermassive black holes, High-redshift galaxies, Galaxy evolution
SKYSURF-5: Probing the Integrated Galaxy Light with a SDSS-SKYSURF Cross-matched Catalog. Project SKYSURF aims to account for the difference between observed integrated background light levels and those expected from galaxy-count measurements using archival Hubble Space Telescope (HST) images. Due to the scarcity of bright objects in a typical HST field of view, Poisson uncertainty and Cosmic Variance can significantly hinder calculations of the total integrated background light from galaxies. Since the existing SKYSURF analysis cannot constrain bright galaxy counts well, we catalog the bright object number density by cross-matching SKYSURF pointings with objects in the Sloan Digital Sky Survey. Here, we present the cross-matched catalogs and measure the distribution of integrated galaxy light from the SDSS objects. We find a median integrated light level in the r-band of 2.45 nW m‑2 sr‑1, consistent with previous findings given the level of incompleteness in SDSS and suggesting that SKYSURF pointings are in general not substantially biased toward object-rich fields on the sky.

Keywords: Sky surveys, Cosmic background radiation, Galaxy counts
Determination of the Abundance of Mercury from the Hg II Line at 5677.10 Å in Late B-type Stars. II. HD 143807 and HD 16727. The weak line of Hg II located at 5677.10 Å is used to measure the mercury abundance in two HgMn stars, HD 143807 (ι CrB) and HD 16727 (11 Per). This line is detected at 3σ above the noise in the adjacent continuum in HD 143807 but not detected in HD 16727. The synthesis of this line, using the current atomic parameters available in NIST, confirms the large overabundance of mercury in HD 143807, about +4.60 dex, in very good agreement with the excess derived in earlier studies from the 3983.93 Å line. At the overabundance expected for HD 16727 (3.90 dex), the line is predicted to contribute a 1% absorption feature which is not seen in the observed spectrum.

Keywords: Mercury-manganese stars, Chemically peculiar stars
Probing Shocked Ejecta in SN 1987A with XRISM-Resolve: The Effects of the Gate Valve Closed. Supernova (SN) 1987A is widely regarded as an excellent candidate for leveraging the capabilities of the freshly launched XRISM satellite. Recent researches indicate that the X-ray emission from SN 1987A will increasingly originate from its ejecta in the years to come. In a previous study, we thoroughly examined the proficiency of XRISM-Resolve in identifying signatures of shocked ejecta in SN 1987A, synthesizing the XRISM-Resolve spectrum based on a state-of-the-art magneto-hydrodynamic simulation. However, following the satellite's launch, a technical issue arose with the XRISM instrument's gate valve, which failed to open, thereby affecting observations with the Resolve spectrometer. Here, we update our analysis, reevaluating our diagnostic approach under the assumption that the gate valve remains closed. We find that, even with the reduced instrumental capabilities, it will be possible to pinpoint the ejecta contribution through the study of the line profiles in the XRISM-Resolve spectrum of SN 1987A.

Keywords: Supernova remnants, Interstellar medium
An Independent Discovery of the 1946 Eruption of the Recurrent Nova T Coronae Borealis and an Early Prediction of a Future Outburst. One of the earliest independent discoveries of the 1946 eruption of the recurrent nova T CrB was by British amateur variable star observer, N.F.H. Knight, on 1946 February 9 at 05.40 UT. Correspondence between Knight and W.M. Lindley, the Director of the British Astronomical Association Variable Star Section, reveals what might be the first prediction of a future eruption in 2026–27.

Keywords: Novae