Sazuna/UAT_keywords huggingface dataset:
Discovery of the Double-mode Pulsation of Variable Star GH Del. The variable star GH Del was classified by the Variable Star Index as an RR Lyrae type variable. The SSV-UAI-GRAV, variable stars section of the UAI (Italian Amateur Astronomers Union), undertook an observation campaign for the star GH Del in order to determine its pulsation mode. GH Del was found to be a double-pulsation RR Lyrae variable star, therefore classified as RRd, with a fundamental period of 0.446375 day (10.7 hr) and the first overtone with a period of 0.330959 day (7.9 hr), whose ratio of 0.7414 confirms the accuracy of the classification.

Keywords: Multi-periodic variable stars, RR Lyrae variable stars, Variable stars, Double-mode pulsation, Double-mode variable stars
Evidence that SOL2012-06-03 Late Phase γ Rays are Produced by &gt;300 MeV Protons from CME-shock Acceleration of Suprathermals from the Flare. A recent paper on SOL2012-06-03 reported the detection for the first time of two distinct phases of &gt;100 MeV γ-radiation indicating separate acceleration processes. But such two-phase emission has been seen before and was first observed in SOL1982-06-03. The second phase is known as Late Phase Gamma-Ray Emission (LPGRE) and was cataloged for &gt;40 solar eruptions, including SOL2012-06-03. Here we provide evidence that the second SOL2012-06-03 π-decay peak is the onset of LPGRE that lasted for &gt;8 minutes. Its delay from the impulsive X-ray peak is consistent with the time it would take flare-produced suprathermal protons to overtake the expanding CME and be accelerated by its shock. The high accelerated ion-to-electron ratio in SOL2012-06-03 and other LPGRE events is consistent with the ratio observed in gradual SEP events produced by shocks and is inconsistent with ratios typically found in impulsive flares and solar energetic particle events produced by reconnection.

Keywords: Solar coronal mass ejection shocks, Solar gamma-ray emission, Solar flares
Ballistic Mass Transfer Necessarily Contracts Orbits in Binary Star Systems. In mass-transferring binary star systems, classical theories show orbital expansion when q = Mdonor/Maccretor &lt; 1. However, these predictions rely on angular momentum conservation. I show that a ballistic prescription, where transferred mass δm carries the donor's instantaneous velocity, exhibits linear momentum conservation but implies a systematic loss of orbital angular momentum corresponding to an effective external torque. Specifically, the fractional loss of orbital angular momentum yields Lf/Li = 1 − f, i.e., fractional angular momentum loss equals fractional mass transferred.

Keywords: Close binary stars, Binary stars, Orbital evolution
The Correlation between Low and High Mass Star Formation: Comparing the Envelope Mass Infall Rate of Low and Intermediate Mass Protostars. Linking low and high-mass star formation is a key goal in star formation theory. Building on the shared framework of inside-out collapse and turbulent core models, forming high-mass sources requires accreting 100─1000× faster than for low-mass stars, for a similar 105 yr age. Because high-mass stars quickly disrupt their environments, we focus on intermediate-mass protostars, expected to accrete 10─100× faster while remaining less disruptive. To better probe environment, we focus on Class 0 protostars. First, with the standard assumption of a 0.5 M⊙ central protostar, we determine infall rates for Class 0 sources from the Herschel Orion Protostar Survey to show a positive correlation between protostellar luminosity and mass infall rate. We then relax this assumption using luminosity as a protostar mass proxy, based on recent studies, to demonstrate that this correlation increases, with intermediate-mass protostars showing 10─40× higher infall rates compared with low-mass stars, consistent with theoretical predictions.

Keywords: Protostars, Star formation
Hidden Companions to Intermediate-mass Stars. XXXV. Unveiling a 1.2M<SUB>⊙</SUB>, 0.38 au Companion to Iota Aquarii. Iota Aquarii is a nearby B-type star that has accrued a large amount of evidence for a close companion. Here we report on a VLTI/GRAVITY observation in which we detected a 1.2M⊙ companion at a projected separation ρ = 7.1 mas ↔ 0.38 au. We conclude that this is the same companion that has been previously reported from direct spectral detection, but that its reported mass (1.00 ± 0.03M⊙) had been somewhat underestimated. However, the Gaia─Hipparcos proper motion change and parallax discrepancy are not readily explained by the companion; if due to another hierarchical outer companion, it would have to be either a M ≲ 0.5M⊙ red dwarf or a white dwarf to remain undetected. *Based on observations collected at the European Southern Observatory, Chile, Program ID 113.26GM.001.

Keywords: Optical interferometry, Multiple stars, B stars
JWST Spectra are Consistent with the Edge-on Star-forming Galaxy Scenario for the "Runaway Supermassive Black Hole". The linear structure reported by P. van Dokkum et al. has been proposed as either a massive stellar wake produced by a runaway supermassive black hole (SMBH) or a bulgeless edge-on galaxy. New JWST/NIRSpec IFU observations by P. van Dokkum et al. target the tip of the structure, where a SMBH would produce a bow shock, whereas a normal galaxy would host an H II region. Using standard Baldwin─Phillips─Terlevich diagrams ([O III]5007/Hβ versus [N II]6583/Hα and [O III]5007/Hβ versus [O II]6716,6731/Hα), we find that the line ratios at the tip fall on the locus of low-metallicity low-extinction H II regions. This region does not overlap with loci typical of shocks in merging galaxies. Thus, these results are consistent with the interpretation that the linear structure is a star-forming galaxy, with the bright knot representing one of its H II regions.

Keywords: Galaxy physics, Galaxy structure, Stellar streams
The Late Spectrum of the Very Fast Fe II Nova V3661 Ophiuchi. V3661 Ophiuchi has the fastest rate of brightness decline of any Fe II type nova observed to date. Here we present its spectrum (from 0.47 to 2.5 μm) 130 days after visible maximum. The spectrum shows both very low and very high excitation permitted and forbidden emission lines. Modeling of the spectrum indicates that the line features arise in a radiation bounded region illuminated by a extremely hot (T &gt; 6 × 105 K) and luminous ionizing source. In addition to producing V3661 Ophiuchi's numerous coronal lines, illumination by the hot source generates a warm, partially ionized zone at the back of the emission line region that gives rise to its lowest excitation emission features.

Keywords: Classical novae
Theoretical Calculation of the Antenna Impedance and Shot Noise at Low Frequencies: Application to Parker Solar Probe. The voltage power spectral density measured around the ambient plasma frequency in space is not affected by spacecraft perturbations that impact traditional plasma analyzers. The spectroscopy of this noise, produced by the quasi-thermal motion of ambient charged particles, is thus an efficient tool for measuring in situ plasma properties in space. In contrast, the spectrum at lower frequencies, which is determined by the parallel antenna resistance due to electric currents, depends on the spacecraft local environment. Recently, X. Zheng et al. erroneously estimated this resistance from Parker Solar Probe (PSP) data. We hereby present a theoretical calculation of this resistance, which determines the shot noise and the receiver gain at low frequencies, and provide a preliminary comparison to PSP/FIELDS data. We also show that this resistance can change the receiver gain in the frequency range used for quasi-thermal noise spectroscopy during PSP inner orbits.

Keywords: Radio spectroscopy, Space plasmas, Space vehicle instruments, Plasma physics, Solar wind
Dynamical Constraints on Temporary Earth Capture of 2022 NX1. Near-Earth objects that are temporarily captured by Earth represent dynamically fragile events that are governed by distinct structured regions of orbital space. The recently discovered asteroid, 2022 NX1, exhibits Earth-like orbital parameters where it transiently associates with Earth as a mini-moon before escaping back to heliocentric space. This study assessed if NX1 can undergo sustained temporary Earth capture using two complementary approaches. These included a controlled phase-space perturbation map in semimajor axis and inclination, and a covariance-consistent Monte Carlo sampling of the full 6 × 6 orbital uncertainty matrix retrieved from the JPL Small-Body Database. Results show no sustained temporary Earth capture events, indicating that this capture is rare and occupies a very narrow capture corridor. These results place strong dynamical constraints on the likelihood of minimoon capture for 2022 NX1 and demonstrate that its nominal trajectory and full correlated uncertainty manifold do not intersect a capture-favourable region of space.

Keywords: Asteroids
On the Claimed <SUP>26</SUP>Al─<SUP>50</SUP>Ti Exclusivity in Presolar Grains. A recent study proposed that calcium─aluminum-rich inclusions (CAIs) and CM hibonites exhibit an exclusivity between 50Ti anomalies and initial 26Al/27Al ratios, such that refractory inclusions with large 50Ti variations necessarily formed from 26Al-poor material, and vice versa. This pattern was attributed to two distinct populations of presolar dust inherited from the protosolar molecular cloud. Reassessment using an updated presolar grain database shows that this proposed Ti─Al exclusivity arises from the contaminated Mg isotope data for a subset of presolar graphite grains. Furthermore, the correlated 48Ca─50Ti signatures among CAIs and hibonites reflect input from rare supernova sources whose dust has not been unambiguously identified. Current presolar grain data, therefore, do not support a presolar-dust origin for the proposed Ti─Al exclusivity.

Keywords: Interstellar dust, Stellar nucleosynthesis
Constraints on CMBR Flux due to High-z Dust Emission. E. Gjergo &amp; P. Kroupa have proposed a new foreground cosmic microwave background radiation (CMBR) component produced by dust associated with the progenitor clouds at z = 15─20 that led to the formation of massive early-type galaxies, calculating that a minimum of 1.4% and a maximum of 100% of the whole CMBR radiation would be produced by this mechanism. Here, I check how much dust emission is compatible with the spectrum of the CMBR monopole flux measurements within the corresponding errors. COBE-FIRAS monopole is fitted to different models with different dust emissivity spectral indexes (β) and dispersion of redshifts of the progenitor clouds (σd). Within the realistic values of β ≥ 0.5, σd ≥ 0.8, the contamination of CMBR flux by high z dust should be &lt;1.3% (95% CL).

Keywords: Dust continuum emission, Cosmic microwave background radiation, High-redshift galaxies
Photometric and Astrometric Information for Sources around HD 163296 Revealed by JWST/NIRCam Coronagraphy. Background stars observed through a circumstellar disk provide valuable benchmarks for investigating the disk's extinction properties. The HD 163296 system is an excellent case study due to its large disk, the clearly visible extinction effects in JWST/NIRCam data, and the presence of numerous background sources within or around its disk. We present the measured contrasts and astrometry of sources surrounding HD 163296 from Cycle 1 JWST/NIRCam coronagraphic observations, which will serve as a useful reference for future studies of the disk's extinction characteristics.

Keywords: Coronagraphic imaging, James Webb Space Telescope, Protoplanetary disks
Comparing Stellar Masses Inferred Using HST and JWST Data in A2744. We analyze stellar mass estimates from James Webb Space Telescope (JWST) and Hubble Space Telescope (HST) photometry, examining discrepancies driven by dust extinction, metallicity, age, and attenuation. Using cross-matched catalogs from the Hubble Frontier Fields and the JWST UNCOVER survey, we construct a homogeneous sample of dwarf galaxies in A2744 with photometric redshifts within z = 0.308 and stellar masses below 109.5 M⊙. While masses are generally consistent between observatories, JWST yields higher estimates in high-extinction, high-metallicity regions, consistent with its infrared sensitivity capturing stellar populations obscured or underestimated in HST-based measurements. Linear regression of age, metallicity, and dust confirms parameter-dependent trends in mass ratios despite low overall correlations. These findings highlight the importance of infrared data for stellar mass determinations and JWST's role in understanding low-mass galaxy evolution.

Keywords: Galaxy clusters, Dwarf galaxies, Galaxy stellar content, Interstellar dust extinction, Galaxy photometry, Spectral energy distribution, Stellar masses, Abell clusters, Infrared photometry
Trial Dispersion Measure Spacing in Fast Radio Burst Searches with HEIMDALL. Fast radio bursts (FRBs) are brief flashes of emission detectable to cosmological distances. Cosmology applications rely on an understanding of how the detected sample relates to the underlying population. To this end we examine the dispersion measure "tolerance" parameter employed by the FRB search tool HEIMDALL and provide the relation between this and minimum search depth. Several FRB samples can be "retro-fitted" using this to more properly account for survey completeness.

Keywords: Surveys, Radio astronomy, Astronomy data analysis, Radio transient sources
Photometric Study of Type Ibn SN 2022ablq Based on g, r, i-band Observations. We present high-cadence photometric observations of the Type Ibn supernova (SN) 2022ablq at 60 Mpc, which exploded at an angular separation of  0.″36  from the nucleus of its host galaxy MRK 0762. Following the initial classification, we initiated an intensive monitoring campaign using the 16 inch Schmidt telescope in Algeria, acquiring CCD images in the SDSS-g, r, and i bands. Our light curves provide a dense coverage of the flux evolution from −5 to +54 days with respect to the epoch of g-band maximum (mpeak = 15.20 ± 0.02 mag at MJD = 59914.08), in agreement with previously published analyses.

Keywords: Astronomical techniques, Supernovae
A Spanish Archival Account of a Dawn Bolide over La Calahorra on 1768 September 18 and Its Temporal Proximity to the Lucé Meteorite Fall. Attention is drawn to an eighteenth-century Spanish archival record describing a conspicuous atmospheric phenomenon observed from La Calahorra (Granada, Spain) at dawn on 1768 September 18. The narrative is consistent with a bright bolide showing persistent trains, fragmentation, and delayed acoustics, with a reported duration of about 6 minutes. Its value lies in providing a dated, localized Iberian eyewitness account that merits explicit cross-reference in historical discussions of the Lucé (France) meteorite fall of 1768 September 13 and of late-September 1768 European meteoric activity, without implying a common physical origin.

Keywords: History of astronomy, Fireballs, Bolides