Sazuna/UAT_keywords huggingface dataset:
Revisiting the Gas-phase Chemical Rate Coefficients at High Temperatures in CLOUDY. A two-body gas-phase reaction rate coefficient can be given by the usual Arrhenius-type formula which depends on temperature. The UMIST Database for Astrochemistry is a widely used database for reaction rate coefficients. They provide fittings for coefficients valid over a particular range of temperatures. The permissible upper-temperature limits vary over a wide range: from 100 to 41,000 K. A wide range of temperatures occurs in nature; thus, it requires evaluating the rate coefficients at temperatures outside the range of validity. As a result, a simple extrapolation of the rate coefficients can lead to unphysically large values at high temperatures. These result in unrealistic predictions. Here we present a solution to prevent the gas-phase reaction coefficients from diverging at a very high temperature. We implement this into the spectral synthesis code CLOUDY which operates over a wide range of temperatures from CMB to 1010 K subject to different astrophysical environments.

Keywords: Interstellar molecules, Reaction rates, Interstellar medium, Astrochemistry
M31N 2008-12a, the Unique Recurrent Nova in Andromeda: A Quick Look at the 2022 Eruption. M31N 2008-12a, located in the Andromeda galaxy (M31), is the best studied recurrent nova. It presents periodic outbursts with about one year between eruptions. However, the annual eruption date varies from year to year. In order to discover the annual eruption and facilitate the multi-wavelength follow-up, a monitoring campaign with nightly cadence is needed. Perez-Fournon et al. and Reyes-Rodriguez et al. reported the discovery of the 2022 M31N 2008-12a eruption with the Las Cumbres Observatory global telescope network in the framework of a three-month monitoring campaign that included also the IAC80 and Isaac Newton telescopes. Here, we discuss the 2022 light curve based on all reported photometry, as well as ATLAS forced photometry, and compare it with the well-studied 2015 eruption discussed in Darnley et al.

Keywords: Light curves, Photometry, Recurrent novae, Novae
The Most Interesting Anomalies Discovered in ZTF DR17 from the SNAD-VI Workshop. The SNAD team has developed an adaptive learning algorithm, named Pine Forest (PF), to enhance anomaly detection in astronomical data. Recognizing the essential role of human engagement in the discovery process, PF presents outliers to a human expert for review, and filters out trees which disagree with the feedback provided. During the sixth annual SNAD workshop (https://snad.space/2023/), held in 2023 July, we applied PF to the Zwicky Transient Facility's DR17 data. Interesting discoveries include long-duration objects such as supernovae, along with fast transients like red dwarf flares and one microlensing event. As a result, new variable stars were identified and labeled in the SNAD knowledge database.

Keywords: Red dwarf flare stars, Astronomy data analysis, Outlier detection, Transient detection, Supernovae
Anomalous Flux Event in the TESS Sector 43 Light Curve of the White Dwarf Photometric Standard HZ 4 was Caused by a Passing Asteroid. Frymire &amp; Ardila reported an anomalous flux variation in the Transiting Exoplanet Survey Satellite (TESS) Sector 43 light curve of the white dwarf HZ 4. We show that this flux variation was caused by the main-belt asteroid 4382 Stravinsky traversing the nearby TESS pixels, and it is therefore not a cause for concern regarding the continued use of HZ 4 as a photometric standard star.

Keywords: Small Solar System bodies, Asteroids, White dwarf stars, Astronomy data analysis, Photometric standard stars
Abundances of Helium, Neon, Magnesium and Phosphorus in the Atmosphere of the Bp He-weak Star HD 175156. The synthesis of two spectral intervals in the optical range allows to determine LTE abundances of helium, magnesium, phosphorus and neon for this evolved B subgiant. Compared to the solar abundances, helium, neon and phosphorus are found to be overabundant by a factor of 5, magnesium by a factor of 4. The helium line at 4471 Å recorded by two different instruments about ten years apart does not vary. Additional information on the abundances of other elements was also inferred: carbon, oxygen, aluminum, sulfur and iron have abundances very close to the solar values, in contrast nitrogen, titanium and xenon require mild overabundances.

Keywords: Helium-weak stars, Chemically peculiar stars
The Behavior of Bp He-weak stars in the far-UV-Paper X: HD 49333. The analysis of four spectra of the B7 He-weak Si star HD 49333 recorded by the SWP camera on board the International Ultraviolet Explorer reveals variations of the far-ultraviolet spectral energy distribution shortwards of 1700 Å over slightly more than 1 day, ie. about 46% of the rotational period. Several Si II, Si III and Si IV vary consistently. Silicon must be distributed in a non uniform manner over the surface of HD 49333 so as to modulate the FUV flux over the rotational period. The profile of the resonance line of C II at 1335 Å does not vary at these two rotational phases.

Keywords: Helium-weak stars, Chemically peculiar stars
The Behavior of Bp He-weak Stars in the far-UV-Paper XI: HD 35456. The analysis of four spectra of the B7 He-weak star HD 35456 recorded by the SWP camera on board the International Ultraviolet Explorer does not reveal any variations of the far-ultraviolet spectral energy distribution shortwards of 1700 Å over slightly more than one rotational period. There is no sign of variability in the numerous Si II, Si III and Si IV lines present in the far-ultraviolet. The profile of the resonance line of C II at 1335 Å remains constant too.

Keywords: Helium-weak stars, Chemically peculiar stars
The Behavior of Bp He-weak Stars in the Far-UV-Paper XII: HD 175156. The analysis of four spectra of the B5 He-variable star HD 175156 recorded by the SWP camera on board the International Ultraviolet Explorer reveals one possible instance of variations of the far-ultraviolet spectral energy distribution shortwards of 1700 Å in spectra separated by 5 yr. Spectra collected over 4 consecutive days with identical exposure times do not vary, which probably rules out the possibility that HD 175156 be a rotational variable. The modeling of the Space Telescope Imaging Spectrograph spectrum reveals the presence of interesting resonance or low lying transitions of C I, N I, S I, P II and several iron-peak elements, which provide interesting diagnostics of the atmosphere of this evolved sub-giant.

Keywords: Helium-weak stars, Chemically peculiar stars
Rotational Stalling Ends when Main-sequence Core Temperatures are at a Minimum. Low-mass stars spin-down over time due to angular momentum loss from magnetized stellar winds. This spin-down is interrupted by an epoch of stalling where stars halt their spin-down for 0.1-2 Gyr. Duration of the stalling epoch is mass-dependent, with higher mass stars spending less time stalled than the lowest mass stars. We demonstrate that the mass-dependent age at which stars resume spinning down correlates with the age where low-mass stars are predicted to achieve their minimum core temperature on the main sequence. This suggests that the stalling epoch is commensurate with a phase in low-mass main-sequence star evolution where stars develop a small convective core and their convective envelopes are growing in mass.

Keywords: M dwarf stars, Stellar interiors, Stellar convective zones, Stellar structures, Stellar convection envelopes, Stellar evolutionary models, Low mass stars, Stellar rotation
Solar Cycle 25 Will Be a Weak-moderate Cycle: an Update. We have previously published several research notes analyzing the solar activity level of current Solar Cycle 25 from the observed sunspot data. pointing out that it exhibits the typical behavior of a weak-moderate cycle. We show in this updated analysis of the solar activity level for Solar Cycle 25 (three year after its beginning) that the current cycle continues being a weak-moderate cycle with values slightly higher than the previous Solar Cycle 24, which was a weak cycle. We also compare the observed sunspot data available until 2023 June with the prediction made by the Solar Cycle 25 Prediction Panel. As conclusion, it seems likely that Solar Cycle 25 will continue to be a weak-moderate one.

Keywords: Solar activity, Solar cycle, Sunspot number
Hidden Companions to Intermediate-mass Stars. VIII. Discovery of a 0.6 M <SUB>⊙</SUB>, 1.7 au Companion to Albali = ϵ Aquarii. A large portion of the visually brightest stars in the night sky are late B to early A-type stars yet our knowledge of their multiplicity is incomplete. Here we report the discovery of a companion to the nearby star Albali (HIP 102618 = ϵ Aquarii), based on a VLTI/GRAVITY interferometric observation. The companion is at a projected separation ρ = 26 mas ↔ 1.7 au and has a K band flux ratio of 0.7%. Through isochrone fitting we find that Albali A is a 400 Myr old 2.8M ⊙ subgiant that has recently evolved off the main sequence, while the newly discovered Albali B is a 0.6 M ⊙ K dwarf. Further astrometric monitoring is needed in order to assess how strongly the stars are expected to interact as the primary expands. *Based on observations collected at the European Southern Observatory, Chile, Program ID 111.24UP.001.

Keywords: Optical interferometry, Multiple stars, B stars, A stars
Overview and Validation of the Asteroseismic Modeling Portal v2.0. The launch of NASA's Kepler space telescope in 2009 revolutionized the quality and quantity of observational data available for asteroseismic analysis. While Kepler was able to detect solar-like oscillations in hundreds of main-sequence and subgiant stars, the Transiting Exoplanet Survey Satellite is now making similar observations for thousands of the brightest stars in the sky. The Asteroseismic Modeling Portal (AMP) is an automated and objective stellar model-fitting pipeline for asteroseismic data, which was originally developed to use models from the Aarhus Stellar Evolution Code. We briefly summarize an updated version of the AMP pipeline that uses Modules for Experiments in Stellar Astrophysics, and we present initial modeling results for the Sun and several solar analogs to validate the precision and accuracy of the inferred stellar properties.

Keywords: Open source software, Asteroseismology, Stellar physics, Computational methods
AGN's Deadness Over Cosmic Time: UVJ Diagrams of X-Ray AGN. Over cosmic time, galaxies tend to separate into a bimodal distribution of "red and dead" or blue and star-forming. We examine whether active galaxies evolve in a similar way, and whether this reveals anything about the complexities of the relationship between an AGN and the host galaxy. We use the Stripe82X survey to identify 3940 X-ray AGN spanning z = 0-2.5, and we measure the rest-frame UVJ colors of each galaxy. We classify AGN as star-forming or quiescent based on their location in a UVJ color diagram. We find that there is not a clear bimodal distribution between AGN in star-forming and quiescent galaxies. Furthermore, the most luminous X-ray sources tend to lie in the star-forming region, which may indicate a correlation between central engine activity and increased rates of star formation.

Keywords: AGN host galaxies, Quenched galaxies, Galaxy colors, Active galaxies, Star formation, Galaxy evolution, Galaxy quenching, Galaxies
Corrected Weight Functions for Stellar Oscillation Eigenfrequencies. Kawaler et al. present a variational expression for the eigenfrequencies associated with stellar oscillations. We highlight and correct a typographical error in the weight functions appearing in these expressions, and validate the correction numerically.

Keywords: Stellar oscillations, Asteroseismology, Astronomical methods, Pulsating variable stars
Understanding Binary Systems-a Comparison between COSMIC and MESA. We compare the evolution of binary systems evolved in the MESA stellar evolution code to those in the COSMIC population synthesis code. Our aim is to convey the robustness of the equations that model binary evolution in the COSMIC code, particularly for the cases of high mass stars with closely orbiting compact object companions. Our larger goal is to accurately model the rates of these systems, as they are promising candidates for the progenitor systems behind energetic, longer lasting, radio bright GRB jets. These systems also may be key contributors to the rates of binary black hole mergers throughout our Universe.

Keywords: Gamma-ray bursts, Theoretical models, Binary stars, Laboratory astrophysics, Stellar physics
A Dataset for Exploring Stellar Activity in Astrometric Measurements from SDO Images of the Sun. We present a data set for investigating the impact of stellar activity on astrometric measurements using NASA's Solar Dynamics Observatory (SDO) images of the Sun. The sensitivity of astrometry for detecting exoplanets is limited by stellar activity (e.g., starspots), which causes the measured "center of flux" of the star to deviate from the true, geometric, center, producing false positive detections. We analyze Helioseismic and Magnetic Imager continuum image data obtained from SDO between 2015 July and 2022 December to examine this "astrometric jitter" phenomenon for the Sun. We employ data processing procedures to clean the images and compute the time series of the sunspot-induced shift between the center of flux and the geometric center. The resulting time series show quasiperiodic variations up to 0.05% of the Sun's radius at its rotation period.

Keywords: Astrometric exoplanet detection, The Sun, Sunspots, Exoplanet astronomy, Solar physics, Astrometry
SN 2023ixf-Temporal Development of Hα Emission. I present a series of spectra of the Type II supernova SN 2023ixf in M101 covering a temporal period of 6 weeks. The latest spectra show a prominent Hα P-Cygni profile with an expansion velocity of 7100 km s-1. In addition to an expanding gas shell, evidence of a possible additional absorption was found. This could be interpreted as an asymmetrical feature in the expanding material of the supernova.

Keywords: Supernovae
Non-LTE Abundances of Helium, Magnesium, and Silicon in the Atmosphere of the Bp He-weak Star HD 175156. The synthesis of the spectral range 4400-4600 Å in UVES spectra of HD 175156 allows to estimate NLTE abundances of helium, nitrogen, oxygen, magnesium and silicon for this evolved B subgiant. The NLTE models used are published models from the BSTAR grid. Compared to the solar abundances, helium and magnesium are found to be overabundant by a factor of 2.0, oxygen and silicon underabundant by a factor of 0.75. Nitrogen has a solar abundance. The overabundances of helium and magnesium are reduced compared to their determinations in Local Thermodynamical Equilibrium.

Keywords: Helium-weak stars, Chemically peculiar stars
LOFAR Detection of Post-starburst Galaxies. We report detection of 104 radio counterparts in a sample of 1204 Sloan Digital Sky Survey-detected post-starburst (PSB) galaxies using the 144 MHz LOw-Frequency ARray (LOFAR) Two-meter Sky Survey Data Release 2 (LoTSS2). The detection rate of optically selected PSB galaxies in the 144 MHz images is ~8.6% while that in the 1.4 GHz was estimated to be ~1.8% using the Very Large Array-Faint Images of the Radio Sky at Twenty centimeter images. Although the 144 MHz radio luminosity shows no significant correlation with luminosity at other wave bands from optical to far-infrared, the fraction of radio-detected PSB galaxies shows a clear trend with absolute magnitude and colors in optical and Wide-field Infrared Survey Explorer infrared bands. A preliminary analysis suggests that the radio emission is dominated by Active Galactic Nuclei.

Keywords: Extragalactic radio sources, Post-starburst galaxies, E+A galaxies
An Analysis of Glacial and Fluvial Morphologies within Impact Craters in the Equatorial Region in Arabia Terra, Mars. Arabia Terra is an ancient and large terrain which is located north of the Martian equator. Due to its ancient nature, it is heavily cratered, and these craters hold evidence of geologic processes during Mars' history. During periods of high obliquity (&gt;35°) it has been suggested that polar ice migration can occur at the lower latitudes. By investigating the impact craters within a localized area in the equatorial region of Arabia Terra, it can be determined how far this migration once occurred. This study aimed to investigate craters ≥1 km in diameter within the 0°N-10°N, 340°E-350°E area of Arabia Terra and determine the frequency of glacial and fluvial morphologies within this region. We divided the search area into two sections, 0°N-5°N, 340°E-350°E and 5°N-10°N, 340°E-350°E, to help identify any latitudinal variations between the glacial and fluvial morphologies.

Keywords: Mars, Craters, Glaciers
No UV-bright Eruptions from SN 2023ixf in GALEX Imaging 15-20 yr Before Explosion. We analyze pre-explosion ultraviolet imaging of the nearby Type II supernova SN 2023ixf in search of precursor variability. No outbursts are seen in observations obtained 15-20 yr prior to explosion to a limit of L NUV ≈ 1000 L ⊙ and L FUV ≈ 2000 L ⊙. The time period of these non-detections roughly corresponds to changes in the circumstellar density inferred from early spectra and photometry.

Keywords: Circumstellar dust, Supernovae
GJ 9404 b: A Confirmed Eccentric Planet, and not a Candidate. Eccentric orbits can be decomposed into a series of sine curves which affects how the false alarm probability is computed when using traditional periodograms on radial-velocity data. Here we show that a candidate exoplanet orbiting the M dwarf GJ 9404, identified by the HADES survey using data from the HARPS-N spectrograph, is in fact a bona fide planet on a highly eccentric orbit. Far from a candidate, GJ 9404b is detected with a high confidence. We reach our conclusion using two methods that assume Keplerian functions rather than sines to compute a detection probability, a Bayes Factor, and the false-inclusion probability periodogram. We compute these using nested sampling with kima.

Keywords: Nested sampling, Radial velocity, Keplerian orbit, Exoplanets
Hidden Companions to Intermediate-mass Stars. IX. Discovery of a 1.5 M <SUB>⊙</SUB>, 1 au Companion to the Primary within the Multiple HIP 57606. HIP 57606 is an intermediate-mass a ~ 88 au visual binary (A+B) that also has 680 au (C) and a 120,000 au (D) companions. Here we report on a VLTI/GRAVITY interferometric observation that revealed that the primary star A is itself a close binary with a 83% K band flux ratio companion at a projected separation ρ = 14.8 mas ↔ 1.0 au. Through isochrone fitting we find masses M Aa = 1.58M ⊙, M Ab = 1.49M ⊙ and M B = 1.15M ⊙ and an age 1 Gyr for the inner triple. The latter will evolve to become a double or triple white dwarf system within about 6 Gyr and which will be under the dynamical influence of the outer companion C. *Based on observations collected at the European Southern Observatory, Chile, Program ID 111.24UP.001.

Keywords: Optical interferometry, Multiple stars, F stars
Study of the Spiral Structure in Galaxies with Multiple Arms: A Preliminary Analysis in NGC 1084 and NGC 3464. We performed a morphological analysis of the spiral structure in two specific galaxies: NGC 1084 and NGC 3464. The main objective of this research is to gain a deeper understanding of the distribution of the spiral structure in disk galaxies by studying their spiral patterns. We applied the two-dimensional fast Fourier transform method and conducted a detailed review of the Fourier spectra and radial density functions (RDFs) to analyze their patterns and characteristics. The initial results reveal that the main modes in the distribution of the spiral arms are m = 1 and m = 2, indicating symmetry. Additionally, specific areas in the RDF are detected where other modes, such as m = 3 and m = 4, exhibit higher relevance, indicating the presence of multiple spiral structures (bifurcations or segments).

Keywords: Spiral arms, Spiral galaxies
New Post-DART Collision Period for the Didymos System: Evidence for Anomalous Orbital Decay. On 2022 September 26, NASA's DART spacecraft impacted Dimorphos, the secondary asteroid in the (65803) Didymos system, so that the efficiency with which a satellite could divert an asteroid could be measured from the change in the systems period. We present new data from the Thacher Observatory and measure a change in period, ΔP = - 34.2 ± 0.1 minutes, which deviates from previous measurements by 3.5σ. This suggests that the system period may have decreased by ~1 minute in the 20-30 days between previous measurements and our measurements. We find that no mechanism previously presented for this system can account for this large of a period change, and drag from impact ejecta is an unlikely explanation. Further observations of the (65803) Didymos system are needed to both confirm our result and to further understand this system post impact.

Keywords: Light curves, Near-Earth objects, CCD photometry, Asteroid satellites
Do the Outburst Properties of M31N 2008-12a Depend on the Time Since the Previous Eruption?. Photometric observations spanning the UV to the near-IR during the nine most recent eruptions (2014-2022) of the extragalactic nova M31N 2008-12a are presented and analyzed in order to explore whether the lightcurve properties for a given eruption, specifically the peak magnitudes and fade rates, are correlated with the time interval since the previous eruption. No significant correlation between the pre-eruption interval and the rate of decline was found, however it appears that the brightness at the peak of an outburst may be positively correlated with the time interval since the previous eruption.

Keywords: Andromeda Galaxy, Recurrent novae, Novae
Hidden Companions to Intermediate-mass Stars. X. Solving for the Mass Ratio in the Spectroscopic Binary Zubenelgenubi = α <SUP>2</SUP> Librae. Zubenelgenubi = α 2 Librae is a nearby double-lined spectroscopic binary that forms a quadruple system with α 1 Librae. The radial velocity amplitude for the rapidly rotating primary is subject to a systematic uncertainty and as a result only a lower limit q = 0.81 to the mass ratio has been previously reported. Here we present a VLTI/GRAVITY interferometric observation of Zubenelgenubi in which we measured a K band flux ratio of 74.7%, resulting in isochrone masses M Aa = 1.95 M ⊙ and M Ab = 1.79 M ⊙ (q = 0.92). The fact that the projected rotational velocities differ by a factor of three despite the similar masses suggests that the stellar spin axes are significantly misaligned in spite of the small semimajor axis a = 0.52 au or alternatively that the primary is a merger product. *Based on observations collected at the European Southern Observatory, Chile, Program ID 111.24UP.001.

Keywords: Spectroscopic binary stars, Multiple stars, Optical interferometry, A stars
The Behavior of Ap/Fp Stars in the Ultraviolet-Paper I: HD 137949 (33 Lib). The analysis of six spectra of the F0Vp EuGdSr star HD 137949 recorded by the SWP camera on board the International Ultraviolet Explorer does not reveal any variations of the far-ultraviolet spectral energy distribution shortwards of 1800 Å over slightly more than 2 yr and a half. The five spectra taken consecutively on 1984 February 23 do not show evidence either for rapid variations of the flux over 2 hr and 50 minutes (whereas the main pulsational period is 8.27 minutes for this rapidly oscillating Fp star). This behavior remarkably differs from the 50% flux variability of δ Scuti (F2 III) in the FUV over its 4 hr and 40 minutes period.

Keywords: Ap stars, Chemically peculiar stars, Rapidly oscillating Ap star