Sazuna/UAT_keywords huggingface dataset:
Exploration of Stellar Variability in 20 s Cadence TESS Data. The introduction of TESS's 20 s cadence mode has given us the opportunity to examine the variation of stellar flux on shorter timescales than ever before. While we find no previously undetected variability at these timescales, we find oscillations outside of the published instability strip in TIC 349902873. We also quantify the stellar variability on specific timescales using the combined differential photometric precision (CDPP). We developed a light-curve creation pipeline for 57 bright stars in TESS' SCVZ across the HR diagram with extant spectra. From the light curves, we reproduced the scaling previously seen between CDPP and magnitude at all timescales in our data set. We also find a potential correlation between CDPP on the shortest timescales and surface gravity, which may be related to convection and oscillations and impact the relative detectability of exoplanet features.

Keywords: Stellar photometry, Variable stars
Improved Limits on Relativistic Interstellar Objects near Earth. It was recently shown that exotic asteroid-sized objects moving at relativistic speeds in the vicinity of the Earth could be detected by their gravitational waves in the LIGO-Virgo-KAGRA experiments, thereby leading to a constraint on their local number density. Here I show that a much stronger limit can be derived from the fact that no such object has ever impacted the Earth.

Keywords: Gravitational waves, Interstellar dynamics
HZ_evolution: A Package to Calculate Habitable Histories. We present HZ_evolution, a Python package to characterize the habitable histories of exoplanets. Given inputs of a planet's current effective flux and host star properties, HZ_evolution calculates its instellation history, the evolution of the star's Habitable Zone (HZ), and the duration the planet spends inside or outside the HZ.

Keywords: Exoplanet astronomy, Exoplanet evolution, Astrobiology, Stellar evolution
Validating Gaia DR3 Pulsating Variable Classifications with TESS. II. 360+ Eclipsing Binaries with δ Scuti and γ Doradus Components. A comprehensive analysis of 75,369 stars from Gaia DR3 has led to the serendipitous discovery of 380 eclipsing binaries featuring δ Scuti and γ Doradus pulsators, 45 eclipsing binaries exhibiting rotational variability, and 8 new RR Lyrae stars. Moreover, this study has confirmed 12,145 δ Scuti stars (including 8710 new) and 8192 γ Doradus stars (including 7531 new). These findings substantially expand the existing catalogs of δ Scuti and γ Doradus stars, now encompassing 98,968 and 19,466 stars, respectively, providing a valuable resource for future studies. The remarkable number of newly identified pulsating binaries underscores the significance of this project in validating Gaia variables.

Keywords: Eclipsing binary stars, Gamma Doradus variable stars, Delta Scuti variable stars, Pulsating variable stars
NIFTY-LS: Fast and Accurate Lomb–Scargle Periodograms Using a Non-uniform FFT. We present NIFTY-LS, a software package for fast and accurate evaluation of the Lomb–Scargle periodogram. NIFTY-LS leverages the fact that Lomb–Scargle can be computed using a non-uniform fast Fourier transform (NUFFT), which we evaluate with the Flatiron Institute NUFFT package (FINUFFT). This approach achieves a many-fold speedup over the Press &amp; Rybicki method as implemented in ASTROPY and is simultaneously many orders of magnitude more accurate. NIFTY-LS also supports fast evaluation on GPUs via CUDA and integrates with the ASTROPY Lomb–Scargle interface. NIFTY-LS is publicly available at https://github.com/flatironinstitute/nifty-ls/.

Keywords: GPU computing, Lomb-Scargle periodogram, Astronomy software
Spectral Index Asymmetries in Double Radio Sources from the VLA Sky Survey. A sample of double radio sources was selected from the Very Large Array Sky Survey to investigate correlations of spectral asymmetries with lobe length ratios and jet-sidedness. The lobe length ratio informs us about the correlation between the lobe pressure and spectral index of FRII lobes from Active Galactic Nuclei. A second analysis was done on the subset with identifiable jets. The correlation of lobe length ratio with spectral index difference was weakly positive, although statistically insignificant. Similarly, there were no statistically significant trends of spectral index difference with jet-sidedness. Further testing with a larger data set may produce a more significant result.

Keywords: Radio jets, Extragalactic radio sources, Radio lobes, Radio loud quasars, Radio galaxies, Radio continuum emission, Radio astronomy
Prospects for the Crossing by Earth of Comet C/2023 A3 Tsuchinshan-ATLAS's Ion Tail. The Earth will pass approximately downstream of the previous position of comet C/2023 A3 (Tsuchinshan-ATLAS) during 2024 October 10–13. We predict that spacecraft at the Sun–Earth Lagrange Point 1, L1, have a significant likelihood to detect pickup ions from the comet, as well as changes in the solar wind associated with the crossing of the comet's ion tail. Given the Earth's magnetosphere is also likely to cross the ion tail, it is possible that geomagnetic signatures associated with this will be observed by spacecraft within the magnetosphere and possible at ground-based magnetometers, as observed during Comet 1P/Halley's apparition in 1910.

Keywords: Long period comets, Solar wind, Space probes, Comet ion tails
Determination of the Abundance of Mercury from the Hg II Line at 5677.10 Å in Late B-type Stars. VIII. HD 175640. The weak line of Hg II located at 5677.10 Å is detected as a faint 1% absorption feature in a NARVAL spectrum of the sharp-lined HgMn star HD 175640. The synthesis of this Hg II feature yields a mercury excess, about +4.00 dex, which is far lower than the +4.40 dex excess derived from the Hg II line at 3983.93 Å. I suggest that the Hg II line at 5677.10 Å is very weak because it is filled by emission in its core, a proposal which had previously been made to explain the weakness of the Hg II line at 6149.47 Å in HD 175640. Several emission lines ascribed to Ti II and Mn II are present in the red part of the spectrum. The synthesis of selected lines of several other elements yields abundances which agree fairly well with those previously derived.

Keywords: Mercury-manganese stars, Chemically peculiar stars
MeerKAT Observations of Procyon at 815.5 MHz. We have conducted observations of the nearby (11.46 ly) star system Procyon, using MeerKAT's UHF (544–1087 MHz) receivers. We produce full-Stokes time and frequency integrated continuum images, as well as total intensity time series imaging at 8 s cadence, and full-Stokes vector-averaged dynamic spectra from the visibilities in order to search for transient activity such as flaring events. We detect no significant radio emission from the system, and estimate an upper limit on the circular polarization fraction of 65% (3σ confidence level). A comparison with previous Very Large Array observations places a 3σ lower limit on the spectral index between 815.5 and 8400 MHz of 0.26, however long-term significant variability over the last 33 yr cannot be ruled out without further, regular radio monitoring of the system.

Keywords: Main sequence stars, Radio interferometry
Discovery of Two New Eruptions of the Ultrashort Recurrence Time Nova M31N 2017-01e. We report the recent discovery of two new eruptions of the recurrent nova M31N 2017-01e in the Andromeda galaxy. The latest eruption, M31N 2024-08c, reached R = 17.8 on 2024 August 06.85 UT, ∼2 months earlier than predicted. In addition to this recent eruption, a search of archival Palomar Transient Factory data has revealed a previously unreported eruption on 2014 June 18.46 UT that reached a peak brightness of R ∼ 17.9 approximately a day later. The addition of these two eruption timings has allowed us to update the mean recurrence time of the nova. We find &lt;T rec&gt; = 924.0 ± 7.0 days (2.53 ± 0.02 yr), which is slightly shorter than our previous determination. Thus, M31N 2017-01e remains the nova with the second shortest recurrence time known, with only M31N 2008-12a being shorter. We also present a low-resolution spectrum of the likely quiescent counterpart of the nova, a ∼20.5 mag evolved B star displaying an ∼14.3 days photometric modulation. *Based on observations obtained with the Hobby-Eberly Telescope (HET), which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximillians-Universitaet Muenchen, and Georg-August Universitaet Goettingen. The HET is named in honor of its principal benefactors, William P. Hobby and Robert E. Eberly.

Keywords: Andromeda Galaxy, Recurrent novae, Novae
Segmenting RFI Using Meta's Segment Anything Model. Radio Frequency Interference (RFI), radio signals from electronics, permeates through astronomical observations using radio telescopes. The interference results in lower sensitivity and higher noise when present. Existing methods, such as TFCrop and RFlag, flag RFI to prevent the contamination of observations. However, these approaches are partially automatic and require manual input to flag RFI. We explore artificial intelligence methods using Meta's Segment Anything Model (SAM) and its parameter space in segmenting RFI. We have developed an open-source pipeline called SamRFI, which segments and flags RFI from measurement sets. We trained SAM's masking weights from Hugging Face to fine-tune the model using Very Large Array data and synthetic waterfall plots injected with RFI. We define a metric, calcquality, to measure the performance of our models based on sensitivity and overflagging. Retrained SAM models identify RFI structure and allow for further exploration in RFI segmentation.

Keywords: Open source software, Astronomy software, Radio telescopes, Radio interferometry, Radio astronomy
Hidden Companions to Intermediate-mass Stars. Upgraded Multiplicity 2 → 3. XXIII. Discovery of a 0.94M <SUB>⊙</SUB>, 9.2 au Companion to the Ap Star Gamma Piscis Austrini A. Gamma Piscis Austrini is a nearby ρ = 4.″1 ↔ 284 au visual binary consisting of an A0Vp primary (A) and an F5V secondary (B). Here we report that the primary is actually a closer binary based on a VLTI/GRAVITY interferometric observation. The newly discovered companion Ab has a K band flux ratio 4.8% ± 0.2% and a projected separation ρ = 143.50 mas ↔ 9.2 au relative to Aa. We estimate isochrone masses M Aa = 2.65M ⊙, M Ab = 0.94M ⊙ and M B = 1.20M ⊙. γ PsA will become a triple white dwarf system within a Hubble time, with a low enough hierarchy for possibly interesting dynamical effects with a timescale P KL ∼ 200 kyr. *Based on observations collected at the European Southern Observatory, Chile, Program ID 113.26GM.001.

Keywords: Optical interferometry, Multiple stars, Ap stars
Extending the Asteroseismic Calibration of the Stellar Rossby Number. The stellar Rossby number (Ro) is a dimensionless quantity that is used in the description of fluid flows. It characterizes the relative importance of Coriolis forces on convective motions, which is central to understanding magnetic stellar evolution. Here we present an expanded sample of Kepler asteroseismic targets to help calibrate the relation between Ro and Gaia color, and we extend the relation to redder colors using observations of the mean activity levels and rotation periods for a sample of brighter stars from the Mount Wilson survey. Our quadratic fit to the combined sample is nearly linear between 0.55 &lt; G BP − G RP &lt; 1.2, and can be used to estimate Ro for stars with spectral types between F5 and K3. The strong deviation from linearity in the original calibration may reflect an observational bias against the detection of solar-like oscillations at higher activity levels for the coolest stars.

Keywords: Stellar magnetic fields, Stellar rotation, Asteroseismology, Stellar properties
TESS Detections of Pulsations in Of?p Stars in the Magellanic Clouds. We used Transiting Exoplanet Survey Satellite observations to search for pulsations in six known Of?p stars in the Magellanic Clouds. We find evidence for pulsational variability in three Of?p stars: UCAC4 115-008604, OGLE SMC-SC6 237339, and AzV 220. Two of them, UCAC4 115-008604 and OGLE SMC-SC6 237339, have been reported to possess kG-order magnetic fields. The obtained results are important to constrain and improve stellar evolution models.

Keywords: Stellar oscillations, Stellar magnetic fields
H<SUB>2</SUB> Fluorescent Emission from the Diffuse Interstellar Medium. Near-IR spectroscopy, which can now be performed at unprecedented sensitivity with the NIRSpec instrument on JWST, can offer a novel probe of diffuse clouds through the observation of H2 fluorescent emissions. Whereas previous observations of interstellar H2 fluorescent emissions were primarily confined to dense clouds lying close to a source of UV radiation, JWST opens the possibility of detecting such emissions from diffuse molecular clouds exposed to the average radiation field in the Galaxy. A simple analytic model is presented to predict the near-IR H2 fluorescent line intensities emitted by diffuse interstellar clouds with a Plummer density profile. It is applicable to sightlines where the column densities of H and H2 have been measured and the peak gas density can be estimated.

Keywords: Interstellar molecules, Astrochemistry, Interstellar line emission, Diffuse interstellar clouds
Direct Evidence for Preburst Stage of Gamma-Ray Burst from GRB 221009A Data. Previous research on Lorentz invariance violation in photons from gamma-ray bursts (GRBs) suggested a scenario where multi-GeV photons could be emitted before lower-energy photons at the GRB source frame. This implies the existence of a new preburst phase in addition to the traditionally identified prompt and afterglow stages observed in earlier studies. In this study, we present direct evidence for this novel preburst phase in GRBs based on recent observations of GRB 221009A. Our analysis leverages data from the Fermi Gamma-ray Burst Monitor and Large Area Telescope detectors of the Fermi Gamma-ray Space Telescope, as well as data from the KM2A detector of the Large High Altitude Air-shower Observatory.

Keywords: Burst astrophysics, Gamma-ray bursts, Particle astrophysics
Sensitivity of Global Oscillation Frequencies to Solar Activity on Short Timescales. Sun's oscillations frequencies vary with the changing magnetic activity and hold a strong positive correlation. While most of the analysis for global modes have been carried out using time series longer than a solar rotation, only a few studies are available showing their variation on shorter timescales. Using Doppler observations from Global Oscillation Network Group during the period 1995–2024, we analyze oscillation frequencies computed on a timescale of nine days and compare them with those obtained from 108 days. We also study their sensitivity in cycles 23 and 24 to the change in solar activity as represented by the 10.7 cm radio flux.

Keywords: Solar interior, Helioseismology, Solar physics, Solar oscillations, Solar activity
At First Sight! Zero-shot Classification of Astronomical Images with Large Multimodal Models. Vision-Language multimodal Models (VLMs) offer the possibility for zero-shot classification in astronomy: i.e., classification via natural language prompts, with no training. We investigate two models, GPT-4o and LLaVA-NeXT, for zero-shot classification of low-surface brightness galaxies and artifacts, as well as morphological classification of galaxies. We show that with natural language prompts these models achieved significant accuracy (above 80% typically) without additional training/fine tuning. We discuss areas that require improvement, especially for LLaVA-NeXT, which is an open source model. Our findings aim to motivate the astronomical community to consider VLMs as a powerful tool for both research and pedagogy, with the prospect that future custom-built or fine-tuned models could perform better.

Keywords: Interdisciplinary astronomy, Astroinformatics, Computational methods
Emission-line Ratios and Ionization Conditions of CEERS Star-forming Galaxies with JWST/NIRSpec. Galaxy emission-line fluxes can constrain star formation rates (SFRs) and interstellar medium (ISM) ionization. We investigate rest-frame optical emission lines of 71 star-forming galaxies (SFGs) at redshift 0.7 &lt; z &lt; 7 using JWST/NIRSpec measurements from the Cosmic Evolution Early Release Science survey. We use Hα to measure SFR and utilize Hubble Space Telescope CANDELS stellar mass estimates to determine specific SFR (sSFR) and compare with the SFG main sequence (MS). We create [O III]λ5008/Hβ versus [Ne III]λ3870/[O II]λ3728 line ratio diagrams. The line ratios appear to correlate with sSFR, and our results suggest that sSFR is the parameter that governs ionization conditions rather than SFR or a galaxy's distance from the MS. These measurements reveal a rich diversity of ISM conditions and physical galaxy properties throughout cosmic time.

Keywords: Active galaxies, Galaxy evolution, Emission line galaxies
Database of Candidate Targets for the LIFE Mission. We present the database of potential targets for the Large Interferometer For Exoplanets (LIFE), a space-based mid-infrared nulling interferometer mission proposed for the Voyage 2050 science program of the European Space Agency. The database features stars, their planets and disks, main astrophysical parameters, and ancillary observations. It allows users to create target lists based on various criteria to predict, for instance, exoplanet detection yields for the LIFE mission. As such, it enables mission design trade-offs, provides context for the analysis of data obtained by LIFE, and flags critical missing data. Work on the database is in progress, but given its relevance to LIFE and other space missions, including the Habitable Worlds Observatory, we present its main features here. A preliminary version of the LIFE database is publicly available on the German Astrophysical Virtual Observatory.

Keywords: Astronomy databases, Exoplanets
The Distance to Dobashi 6193—A Dark Cloud Shadowing the eROSITA Bubbles. We focus on a prominent gas cloud, Dobashi 6193, toward the western base of the northern eROSITA bubble (eRObub). It can potentially put a tight distance constraint on the eRObubs and clarify the emissions of the Loop I superbubble from the eRObubs. We found its distance to be 700 pc based on Gaia DR3 stellar extinction and parallax measurements, making it one of the most distant clouds shadowing the eRObubs well above the Galactic disk.

Keywords: Interstellar dust extinction, Stellar parallax, Hot ionized medium, Diffuse x-ray background, Superbubbles
The Spectrum of C/2023 A3 Indicates a Depleted Composition. We report a spectroscopic observation of comet C/2023 A3 using an 80 mm apochromatic refractor equipped with a custom-built spectrometer with a resolution of R ∼ 2500 on the night of 2024 October 4. Sodium D lines were detected prominently, while no other emission lines, particularly carbon-bearing species, were observed, which suggests that comet C/2023 A3 may be carbon-depleted. The mobility and flexibility of our observational setup highlight the value of amateur telescopes in observing low-altitude targets like C/2023 A3 as a complement to professional facilities.

Keywords: Long period comets, Comet nuclei, Spectroscopy, Comets
Characterization of Line Ratio Variations in Orion A. Here we use a new method to study the correlation between different molecular emission lines in star-forming molecular dust clouds. This method is applied to maps from the Line Emission as a Tool for Galaxy Observations project (12CO, 13CO, C18O, N2H+, CCH, HCN, and CN) in Orion A. Our data shows the correlation properties change within dust clouds in Orion A, suggesting that the physical properties change as well. We are preparing our code and data to be publicly accessible in an online repository.

Keywords: Astrophysical dust processes, Radio astronomy, Interstellar molecules, Molecular clouds
Robust Support for Semi-automated Reductions of Keck/NIRSPEC Data Using PypeIt. We present a data reduction pipeline (DRP) for Keck/Near InfraRed SPECtrograph (NIRSPEC) built as an addition to the PypeIt Python package. The DRP is capable of reducing multi-order echelle data taken both before and after the detector upgrade in 2018. As part of developing the pipeline, we implemented major improvements to the capabilities of the PypeIt package, including manual wavelength calibration for multi-order data and new output product that returns a coadded spectrum order-by-order. We also provide a procedure for correcting telluric absorption in NIRSPEC data by using the spectra of telluric standard stars taken near the time of the science spectra. At high resolutions, this is often more accurate than modeling-based approaches.

Keywords: High resolution spectroscopy, Astronomy software, Infrared spectroscopy, Astronomy data reduction
When will the Next T CrB Eruption Occur?. The first eruption of the periodic nova T CrB for eighty years is anticipated soon, though with an unknown date. A refinement of the future eruption date is investigated. The investigation is based on the combination of the previous eruption dates and on the orbital ephemeris of the binary system, without any hypothesis on the eruption mechanism. It is predicted that the next eruption should appear around 2025 March 27 or November 10, or later.

Keywords: Recurrent novae
GRANDMA Observations of SN 2023wrk, a Luminous Type Ia Supernova with Significant Unburned Carbon in the Outer Ejecta. First detected on 2023 November 4 by the Gravitational-wave Optical Transient Observer, SN 2023wrk is a Type Ia Supernova at 40 Mpc, with significant unburned carbon in the outer ejecta. In this note, we present photometric and spectroscopic observations and analysis conducted by the Global Rapid Advanced Network Devoted to the Multi-messenger Addict over a 115 days period, which includes 78 days of measurements. The observations were contributed by both amateur and professional astronomers. J. Liu et al. analyzed the physical processes involved, and compared the evolution of color and spectral lines. We conclude that SN 2023wrk is the second 1999aa-like object with strong carbon absorption lines that has ever been found, which enriches our understanding of the subclass of 1999aa-like SNe.

Keywords: Amateur astronomy, Ejecta, High energy astrophysics, White dwarf stars, Amateur astronomers, Transient sources, Gravitational wave astronomy, Type Ia supernovae, Time domain astronomy, Gravitational waves, Transient detection, Supernovae
Updated Forecast for TRAPPIST-1 Times of Transit for All Seven Exoplanets Incorporating JWST Data. The TRAPPIST-1 system has been extensively observed with JWST in the near-infrared with the goal of detecting atmospheric transit transmission spectra of these temperate, Earth-sized exoplanets. A byproduct has been much more precise times of transit compared with prior available data from Spitzer, Hubble Space Telescope, or ground-based telescopes. In this note we use 23 new timing measurements of all seven planets in the near-infrared from five JWST observing programs to better forecast and constrain the future times of transit in this system. In particular, we note that the transit times of TRAPPIST-1h have drifted significantly from a prior published analysis by up to tens of minutes. Our newer forecast has a higher precision, with uncertainties ranging from 7 to 105 s during JWST Cycles 4 and 5. This forecast will help to improve planning of future observations of the TRAPPIST-1 planets, while we postpone a full dynamical analysis to future work.

Keywords: Exoplanet dynamics, James Webb Space Telescope, Transit timing variation method, Exoplanet systems