Sazuna/UAT_keywords huggingface dataset:
The Early Post-outburst Infrared Spectrum of the Stellar Merger V1309 Scorpii (Nova Scorpii 2008). In this paper we present a 0.8–2.4 μm spectrum of the stellar merger V1309 Scorpii (Nova Scorpii 2008). The spectrum was acquired within three days of discovery and a day before maximum light and has the appearance of a F supergiant. It is dominated by H I line absorptions and closely mimicks that of a classical novae with a massive ejected shell shortly after outburst. The spectrum also displays Fe II features—all in emission—and absorption lines due to C I, S I and Ca II. Weak molecular absorption from carbon monoxide may also be present.

Keywords: Stellar mergers
SPOCK 2.0: Updates to the FeatureClassifier in the Stability of Planetary Orbital Configurations Klassifier. The Stability of Planetary Orbital Configurations Klassifier (SPOCK) package collects machine learning models for predicting the stability and collisional evolution of compact planetary systems. In this paper we explore improvements to SPOCK's binary stability classifier (FeatureClassifier), which predicts orbital stability by collecting data over a short N-body integration of a system. We find that by using a system-specific timescale (rather than a fixed 104 orbits) for the integration, and by using this timescale as an additional feature, we modestly improve the model's AUC metric from 0.943 to 0.950 (AUC = 1 for a perfect model). We additionally discovered that ≈10% of N-body integrations in SPOCK's original training data set were duplicated by accident, and that &lt;1% were misclassified as stable when they in fact led to ejections. We provide a cleaned data set of 100,000+ unique integrations, release a newly trained stability classification model, and make minor updates to the API.

Keywords: Exoplanet dynamics, N-body simulations, Orbital evolution
A Search for Eclipse Cycles Similar to the Hypersaros: Columbus and the Lunar Eclipse of 2025 March 14. The total lunar eclipse on 2025 March 14 UT occurs nearly exactly 521 yr (one Hypersaros) after a similar eclipse on 1504 March 1 UT that is renowned for its importance to the voyage of Columbus to Jamaica. Eclipses separated by a Hypersaros have similar depths, appear very close to the same location in the sky, and occur at nearly the same time of year. This paper summarizes the results from a search for analogous cycles within the Five Millennium Catalogs of Lunar and Solar Eclipses. Under the two simple constraints of similar eclipse dates relative to the vernal equinox and similar paths of the Moon through the Earth's shadow, the most common time intervals between lunar eclipses separated by less than 1000 yr are the 521 yr Hypersaros and a 633 yr period of the Icosa-Inex-Triple-Saros. Notable cycles at longer periods occur at 1154, 1284, 1787, 1917, and 2308 yr.

Keywords: Eclipses, Saros cycle, History of astronomy
Hidden Companions to Intermediate-mass Stars. XXV. Uncovering a 2.6 M<SUB>⊙</SUB>, 0.36 au Companion to m Carinae (Plus Evidence for a M ∼ 0.5M<SUB>⊙</SUB> Outer Companion). m Carinae is a B9V star and the most massive member of the nearby and young (13 Myr) Carina association containing about 25 stars. It has been reported as SB2 in the past but the nature of the companion was only vaguely assessed. Here we report on a VLTI/GRAVITY interferometric observation which revealed that the companion has a K band flux ratio of 92% at a projected separation ρ = 5.20 mas ↔ 0.36 au. Isochrones based on the photometry imply masses MAa = 2.75M⊙ and MAb = 2.63M⊙. This companion, however, cannot explain either the Gaia-Hipparcos acceleration of m Car or its X-ray emission. We suggest that both are most likely caused by an additional M ∼ 0.5M⊙ companion at a separation of about 20 au and which could be easily detected with modern Adaptive Optics observations. *Based on observations collected at the European Southern Observatory, Chile, Program ID 112.25QQ.001.

Keywords: Optical interferometry, Multiple stars, B stars
Investigating the Nature of X-Ray Sources in the Andromeda Galaxy Using Chandra and Hubble Data. Using data from the Panchromatic Hubble Andromeda Treasury (PHAT) program and the Chandra X-ray Observatory, we analyzed X-ray sources in the Andromeda Galaxy (M31). From this we identified 799 X-ray sources within the PHAT region. Our analysis suggests that the X-ray sources consist mainly of high-mass X-ray binaries (HMXBs) with a few low-mass X-ray binaries. These sources show a cumulative X-ray luminosity function consistent with other star-forming galaxies dominated by HMXBs. The population of evolved stars within M31, as identified by color─magnitude diagrams, further supports the hypothesis that these X-ray sources are predominantly X-ray binaries.

Keywords: Extragalactic astronomy, Stellar classification, High energy astrophysics
Antares: Variability of the Nearby M Supergiant and Core Collapse Type II Supernova Progenitor. Antares A is a bright ∼0.6–1.3 mag irregular/semi-regular variable M1.5 Iab star. Antares with Betelgeuse (M2.5 Iab) are the two nearest red supergiant, core-collapse Type-II supernova progenitors. Unlike Betelgeuse, Antares A has a resolved companion (B4V: Antares B) and is near its birthplace in the Upper Scorpius OB Association. We analyzed ∼70 yr of photometry mostly from the American Variable Star Observers database and Hipparcos. Due to its southern declination (‑26 4), accurate visual photometry from mid-northern latitudes is difficult where air masses often exceed z &gt; 3.0. As a result, Antares has fewer, generally lower quality visual-magnitude measurements. We vetted the observations, applying less weight to the visual observations made at high airmasses. The photoelectric observations were given higher weights. Period analyses were conducted utilizing the CLEANest Power-Spectrum and weighted wavelet Z-transform Wavelet programs provided in the Peranso-3 period analysis software. The results are compared to Betelgeuse.

Keywords: M supergiant stars, Stellar pulsations
T CrB: Detection of a Short Flare in 2024 November. We detected an ionization flare on 2024 November 18 during a high cadence spectroscopic monitoring campaign on T CrB (https://aras-database.github.io/database/index.html) before its anticipated next nova outburst with a duration of between 12 and 32 days, during which optical emission lines of He II and [O III] appeared for the first time since the end of the very high active state 2015–2023.

Keywords: Symbiotic binary stars, Recurrent novae
Detection of a Peculiar Noise Type in the TESS "Fast" Light Curves. We present the detection of a peculiar high-frequency noise component in the 20 s cadence Simple Aperture Photometry light curve of Transiting Exoplanets Survey Satellite. This effect (labeled as blue noise) may be attributed to the pointing instability (also known as satellite jitter) of the satellite. We present a common technique used in the mitigation of the jitter, by decorrelating against the subpixel position of the photo-center of the point-spread function of the star. We also show that a simple linear or polynomial technique may not yield satisfactory corrections, as the behavior or attitude of the noise properties may change considerably throughout the light curve.

Keywords: Exoplanet astronomy, Space telescopes, Red noise, Photometry
Broadening of the Main Sequence of a Star Cluster by Undetected Binaries. This note is concerned with the spread in apparent magnitudes (or absolute magnitudes) of main-sequence stars in a star cluster. I specifically consider the effect of binary stars in broadening the main sequence. I calculate the probability density function (pdf) of the magnitude at a given photometric color, including the effects of binarity. An expression is developed which employs plausible models for the pdfs of the magnitudes of the primary and secondary stars, as well as the distribution of secondary-to-primary mass ratio. The expression for the pdf is dependent on σ, the fractional variation of primary and secondary, and A, the fraction of stars that are binaries. The expression can be used to determine the fraction of binaries in a sample of stars taken from a star cluster, or to limit long term variations in the luminosity of solar type stars.

Keywords: Solar activity, Open star clusters, Solar analogs, Solar cycle
Arcminute Microkelvin Imager Observations at 15.5 GHz of Multiple Outbursts of Cygnus X-3 in 2024. We report radio monitoring of Cygnus X-3 at 15.5 GHz during 2024 with the Arcminute Microkelvin Imager. Observations were made on 296 days throughout the year, and reveal five radio outbursts to multi-jansky levels, peaking in February, April, June, July and August. The brightest peak, with ≈16 Jy, was on June 27th.

Keywords: Galactic radio sources, High mass x-ray binary stars, Variable radiation sources, Radio continuum emission
Optical Polarimetry of WR 1 Consistent with a CIR and 17 days Rotation. New visible-band linear polarimetry of the star WR 1 (HD 4004) is presented. This early N-rich Wolf–Rayet star has previously been reported as harboring a Corotating Interaction Region structure threading its wind, implying a stellar rotation period of 16.9 days. Polarization measurements in the Q ‑ U diagram obtained over a span of more than 5 weeks with sampling every few days are revealing (a) variability consistent with the previously reported period and (b) a loop morphology consistent with theoretical models.

Keywords: Wolf-Rayet stars, Stellar rotation, Polarimetry
Determination of the Abundance of Mercury from the Hg II Line at 5677.10 Å in Late B-type Stars. XV. HD 79158 (36 Lyncis). The weak line of Hg II located at 5677.10 Å is not detected in high signal-to-noise ratio NARVAL I profiles of the Helium-weak star HD 79158. This is probably due to the large projected equatorial velocity, the moderate excess of mercury in this star and a lower signal-to-noise ratio of the NARVAL I profile at this wavelength. The synthesis of various spectral intervals also yields new measurements of the abundances of helium, magnesium, aluminium, silicon, titanium, chromium, manganese, iron, yttrium and mercury. The abundance of mercury is estimated from the commonly used Hg II line at 3983.94 Å which is broadened by rotation and blended with the neighbouring line Y II at 3982.59 Å. Most of these new measurements agree roughly with previous measurements.

Keywords: Helium-weak stars, Chemically peculiar stars
Rosette Nebula Outburst Gaia 24djk from the Young Stellar Object V557 Mon. A previously faint young stellar object (YSO), V557 Mon, rapidly brightened in late 2024 and is currently at least ΔG = 3.3 mag brighter than its typical pre-outburst brightness. The ongoing outburst is identified in the Gaia Alerts system as Gaia24djk. We obtained a 1–2.5 μm spectrum of the object and find the spectrum is dominated by line emission and continuum excess consistent with rapid YSO accretion, similar to the star EX Lup during its outburst state. We speculate that the burst, which has not yet reached its peak brightness, may become an FU Ori outburst, which would be evidenced by the emission spectrum turning into an absorption spectrum.

Keywords: Optical bursts, Young stellar objects, Infrared spectroscopy, Stellar accretion
The Eruptive Nature of the Variable Star CzeV195. CzeV195 is a variable star discovered by Jaroslav Trnka (CzeV) in 2017 and classified at the Variable Star Index as a suspected EA-type variable star. The SSV-UAI-GRAV research section of the Unione Astrofili Italiani, undertook an observing campaign with ground-based telescopes in 2024 June and July. The star turned out to be an eclipsing variable of the EA type with a period of 0.604905 days. It was possible to detect an oscillation between the primary and secondary minima, typical of chromospherically active stars such as BY Draconis. Thanks to Zwicky Transient Facility and All-Sky Automated Survey for Supernovae photometry, ourbursts typical of UV Cet eruptive stars were detected. Czev195 was ultimately classified after our studies as an EA+BY+UV.

Keywords: Eruptive variable stars, Eclipsing binary stars, BY Draconis stars, Multi-periodic variable stars, UV Ceti stars
Solar Cycles: Can they be Predicted?. The solar magnetic field, thought to be generated by the motion of plasma within the Sun, alternates on the order of 11 yr cycles and is incompletely understood. Industries rely on accurate forecasts of solar activity, but can solar cycles be predicted? Of more than 100 predictions for cycle 25, most underestimated the amplitude (peak sunspot number). Fewer predictions were made for the timing of solar maximum, but timing predictions seem to be performing better than amplitude predictions. Reasons for inaccurate prediction are suggested, and perspectives are given on how future studies might improve upon the extant literature.

Keywords: Solar cycle, Astronomy data modeling, Sunspot number, Sunspots, Sunspot cycle
Is Virtual Impactor 2024 YR<SUB>4</SUB> Related to the Porangaba Meteorite Fall?. The Porangaba meteorite fall was the result of a daylight fireball observed on 2015 January 9, in a large area of Sao Paulo, Brazil. It was considered a sporadic bolide not associated with any known meteor shower. Here, we show that the orbital properties of the recently discovered virtual impactor 2024 YR4 (impact probability 0.021) are a possible match to those of the meteoroid responsible for the Porangaba meteorite fall with a probability of 0.050. Our data mining exploration also uncovered a group of seemingly related objects that includes virtual impactors 2017 UW5, 2018 GG4, 2019 SC, 2020 MQ61, and 2020 DM3.

Keywords: Solar system, Asteroids
Validation of Two Earth-mass Planets Orbiting GJ 1002. GJ 1002 is reported to host two Earth-mass planets in the habitable zone. We applied frequency-domain techniques for validating planet discoveries to the ESPRESSO and CARMENES radial velocity (RV) and cross-correlation full width at half maximum time series. Siegel's test applied to Welch's power spectrum estimates suggests that periodicity in the RV time series may not be statistically significant. The frequency response to a sinusoid with the frequency of planet b, or pseudowindow, shows excess power near the frequency of planet c. Finally, a Monte Carlo experiment where we create new RV time series realizations by adding white noise to original data reveals that the highest periodogram peak sometimes occurs at half the frequency of planet c. More extreme-precision observations are required to confirm RV oscillations and constrain the rotation period.

Keywords: Stellar activity, Period search , Radial velocity, Stellar rotation, Time series analysis
Correcting the Coordinates for Old Novae V707 Sco and V721 Sco. V707 Sco (Nova Sco 1922) and V721 Sco (Nova Sco 1950 no. 3) were both faint, poorly observed, classical novae near the Sting of the Scorpion. Both have substantially incorrect cataloged coordinates. I have recovered the correct coordinates by going back to the original Harvard archival plates. V707 Sco is at J2000 17:48:25.31, ‑36:36:37.0. V721 Sco is at J2000 17:42:14.62, ‑34:41:41.0. With these new positions, deep searches should turn up the quiescent counterparts, with their study adding to the large program of measuring the demographics of novae.

Keywords: Novae
The Infrared Spectrum of the Stellar Merger V1309 Scorpii One Month After Outburst. An infrared spectrum from 0.8 to 5.1 μm is presented for the stellar merger V1309 Scorpii (Nova Scorpii 2008) from 32 days after discovery and 28 days after maximum light. The spectrum resembles a late-type M-supergiant in its overall shape and the presence of strong molecular absorptions from CO, H2O, TiO, and VO but differs with the addition of H I and He I emission lines and prominent emission from Ca II. It is similar to stellar merger V838 Monocerotis (Nova Mon 2002) in displaying several emission lines of Ti I and weak absorption lines of Sr II but differs by producing He I emission.

Keywords: Stellar mergers
On the Stability of Retrograde Orbits Between Jupiter and Saturn. Between Jupiter and Saturn about 1000 minor bodies exist in orbits with large eccentricities. Previously, this domain has been studied for asteroids with relatively small eccentricities indicating regions of stability with large escape times of up to several hundred million years. Orbits with large inclinations were particularly stable, even for massive planets. However, studies about retrograde orbits are sparse or missing. Here we investigate the stability behavior of massless bodies between Jupiter and Saturn ranging from perpendicular (i = 90∘) to retrograde motion (i = 180∘). Besides theoretical analyses of the solar system, our work may be of interest to future studies of exosolar planetary systems.

Keywords: Asteroid satellites, Small Solar System bodies
Effects of Localization Precision on Identified Fast Radio Burst Host Galaxy Magnitudes. We study the potential bias in the identification of fast radio burst (FRB) host galaxies due to radio localization uncertainty. Using a sample of FRBs localised to typically   $0\mathop{.}\limits^{^{\prime\prime} }5$  &lt;?MML  0   .   ″   5 ?&gt;  by the Australian Square Kilometre Array Pathfinder, we artificially increase the localization uncertainty up to 10″, and re-run the Probabalistic Association of Transients to their Hosts algorithm to determine the most likely host galaxy. We do not find evidence of a significant change in identified hosts until the localization precision is worsened to 2″ or greater.

Keywords: Radio bursts, Time domain astronomy, Galaxies, Radio transient sources
The V-band Variability of NGC 4151. We present V-band continuum light curves of the active galactic nucleus (AGN) in NGC 4151 created from a new photometric monitoring campaign with the Las Cumbres Observatory network. A total of 336 images were collected from 2023 December to 2024 June, with an average cadence of ∼2 images per day. Using aperture photometry and image subtraction, we constructed continuum light curves. Though both techniques generated similar light curves and demonstrated AGN variability on the scale of ΔV ≈ 0.4 mag, the galactic starlight contribution to the aperture photometry light curve produced a flux offset of ∼19% within a circular aperture of radius 3  $\mathop{.}\limits^{^{\prime\prime} }$  &lt;?MML    .   ″   ?&gt; 1. The final light curves from this work will be compared against the variability of the broad emission lines to constrain the mass of the supermassive black hole and to model the broad-line region kinematics and geometry in NGC 4151.

Keywords: Supermassive black holes, Seyfert galaxies
Determination of the Abundance of Mercury from the Hg II Line at 5677.10 Å in Late B-type Stars. XVI. HD 33904 (μ Lep). The weak line of Hg II located at 5677.10 Å is clearly detected as a 3% absorption feature in a series of FEROS and HARPS spectra of the HgMn star HD 33904. The synthesis of this Hg II feature yields a mercury excess, about +5.70 dex, for the FEROS and the HARPS spectrum which is about half of the +6.00 dex excess previously derived from the Hg II line at 3983.93 Å. There is no evidence for variability of this line in the FEROS nor HARPS spectra used in this work.

Keywords: Mercury-manganese stars, Chemically peculiar stars
High-resolution Spectroscopy of the Wolf–Rayet Nebula NGC 6888. The iconic Wolf–Rayet bubble NGC 6888 represents a classical shell driven by stellar winds. Its unique properties make it an important target for studying the material ejected from its progenitor star. In order to construct a comprehensive kinematic model of the WR nebula NGC 6888, we report here the preliminary results in the lines of [O III], Hα and [N II] using Manchester Echelle Spectrometer high-resolution spectroscopy from the OAN-SPM. (Based on observations collected at the Observatorio Astronómico Nacional (OAN), operated in Mexico by UNAM.) We found that the expansion velocities associated with the shell range from 64 to 75 km s‑1 for the Hα and [O III] lines, respectively.

Keywords: Wolf-Rayet stars, Gaseous nebulae, Spectroscopy
Candidate C III] Emission in a Massive, Compact, z ∼ 4.5 Galaxy. We report candidate C III]1907,1909 Å emission at 3.6σ at z = 4.521 using MultiObject Spectrometer for Infra-Red Exploration Y-band spectroscopy of COS J100029.9+021142.5. The galaxy was a filler target for the Web Epoch of Reionization Lyman-alpha Survey, a large spectroscopic campaign targeting Lyα in the Epoch of Reionization. Based on Bayesian Spectral Energy Distribution fitting, we find consistency between the photometric (zp = 4.46 ± 0.09) and spectroscopic (zspec = 4.521 ± 0.002) redshifts and measure the stellar mass to be  .

Keywords: Galaxy spectroscopy, High-redshift galaxies
From Non-detection to Detection: Atacama Compact Array Mosaic Observations of Faint Extended [C I] Emission in NGC 7679. We report the detection of [C I] 3P1–3P0 emission in the nearby galaxy NGC 7679 using the Atacama Compact Array (ACA) of the Atacama Large Millimeter/submillimeter Array (ALMA). In T. Michiyama et al., [C I] 3P1–3P0 emission in NGC 7679 was reported as undetected based on ACA observations conducted in 2019 (ALMA Cycle 6). These observations had ∼1 minute on-source time and used a single pointing with a field of view (FoV) of ∼20″. In 2023 (Cycle 9), we carried out mosaic observations using seven pointings with an FoV of ∼27″ and 4–5 minutes on-source per pointing. The additional data have significantly improved the line sensitivity, uv-sampling, and noise uniformity across the galaxy disk. Our Cycle 9 observations confirm the presence of extended [C I] 3P1–3P0 emissions in NGC 7679, which was completely missed in the Cycle 6 observations due to insufficient sensitivity and uv-sampling. This highlights the basic technical challenges of estimating the total flux by interferometric observations with sparse uv sampling.

Keywords: Extragalactic astronomy, Submillimeter astronomy, Interstellar medium
Upper Limits on GeV Gamma-Ray Flux from the Ultra-long Period Neutron Star PSR J0901‑4046. PSR J0901‑4046 is a radio neutron star with an ultra-long spin period of 75.88 s. We search 14 yr of Fermi-LAT observations for evidence of steady gamma-ray emission. We find no evidence of gamma-ray emission and set a 95% upper limit on the flux from PSR J0901‑4046 of 1.4 × 10‑9 photons cm‑2 s‑1 assuming a power law with exponential cutoff spectrum.

Keywords: Neutron stars, Pulsars, Gamma-ray astronomy, Gamma-rays, Radio pulsars
SKYSURF-7: Exploring PSF Contamination in Diffuse Sky Measurements with HST. Project SKYSURF constrains Extragalactic Background Light and diffuse light using over 200,000 images in the Hubble Space Telescope (HST) archive. However, it is possible that the faint wings of the point-spread function (PSF), which characterizes the distribution of light in individual stars and galaxies in an image, could contaminate or skew measurements of the sky surface brightness (sky-SB). Using the HST Wide Field Camera 3/IR F140W filter, we investigate whether a realistic HST PSF contaminates SKYSURF sky-SB measurements. Using the image simulation tool GalSim we characterize potential PSF contamination by comparing a simplistic modeled Gaussian PSF and a more realistic empirical HST PSF. We find PSF contamination is negligible for our sky-SB measurements, calculating a contribution of 0.00054 MJy sr‑1 due to PSF contamination, compared to current measurement uncertainties of 0.005 MJy sr‑1.

Keywords: Hubble Space Telescope, Cosmic background radiation
2005 VL1 is not Venera-2. The solar system object 2005 VL1 passed close to Earth in late 1965. It has been suggested that it is actually the space probe Venera-2. However, a comparison of the orbits presented in this note demonstrates that the proposed association is incorrect.

Keywords: Deep space probes, Space probes, Asteroids, Near-Earth objects