Sazuna/UAT_keywords huggingface dataset:
Class I/II Jets with JWST: Mass-loss Rates, Asymmetries, and Binary-induced Wigglings. We present JWST NIRSpec spectroimaging observations of jets from four edge-on protoplanetary disks that exhibit clear signatures of MHD disk winds. Bipolar jets are detected and spatially resolved in over 30 shock-excited forbidden lines, multiple Paschen and Brackett series lines of atomic hydrogen, and the high-energy excitation line of atomic helium (1.083 μm). This helium line is the brightest jet tracer toward HH 30 and FS TauB, which also exhibit asymmetric intensity between their red- and blueshifted lobes in all tracers, including the [Fe II] and He I lines. Extinction maps reveal no significant differences across the lobes, suggesting an asymmetric jet-launching mechanism rather than environmental effects. Diagnostic line ratios yield consistent shock speeds of 50–60 km s‑1, jet ionization fractions of 0.1–0.2, and pre-shock electron densities of 1000 cm‑3. Combined with pixel-by-pixel electron density maps and [Fe II] line luminosities, we estimate jet mass-loss rates using three independent methods, averaging around a few 10‑9 M⊙ yr‑1. We estimate the accretion rates for these sources as 10× the jet mass-loss rates and find them to match well with the independently derived accretion estimates of other Class II sources in the Taurus star-forming region. Owing to JWST's high precision, we also investigate jet wiggling and find Tau 042021 to showcase the perfect case of mirror-symmetric wiggling, which can only be explained by the motion of the jet source around a stellar companion. Modeling this wiggling suggests Tau 042021 to host a 0.33 and 0.07 M⊙ binary at the center with a binary separation of 1.35 au and an orbital period of 2.5 yr.

Keywords: Jets, Infrared spectroscopy, Stellar jets, T Tauri stars, James Webb Space Telescope, Protoplanetary disks, Planet formation
Dazzle: Oversampled Image Reconstruction and Difference-imaging Photometry for the Nancy Grace Roman Space Telescope. We present algorithms and software for constructing high-precision difference images to detect and measure transients, such as microlensing events, in crowded stellar fields using the Nancy Grace Roman Space Telescope. Our method generates difference images by subtracting an oversampled reference image, with iterative masking to address outlier pixels. We also provide an analytic correction for small dither offset errors. Microlensing detection is achieved through a three-dimensional matched-filtering technique, optimized with Gaussian kernels to capture varying event durations, and verified through synthetic tests with high recovery rates. Transient photometry is performed via PSF fitting on difference images, using Nelder─Mead optimization for subpixel accuracy. The software, Dazzle, is available as an open-source Python package built on widely used libraries, offering accessible tools for the detection and characterization of transient phenomena in crowded fields.

Keywords: Stellar photometry, Galactic center, Infrared telescopes, Gravitational microlensing, Transit photometry
TOI-6695: A Pair of Near-resonant Massive Planets Observed with TESS from the WINE Survey. We present the discovery and characterization of a pair of warm Jovian-mass exoplanets orbiting the Sun-like star TOI-6695, based on Transiting Exoplanet Survey Satellite (TESS) transits and precise radial velocity (RV) measurements obtained with FEROS, HARPS, CHIRON, CORALIE, and PFS. The transiting exoplanet TOI-6695b has an orbital period of ∼80.4 days, a radius of 0.85Rjup, and a mass of 0.21Mjup. The outer planet has a minimum mass of 1.45Mjup and an orbital period of about 242.4 days, confidently constrained by the Doppler time-series data. The TOI-6695 exoplanet system exhibits transit-timing variations due to the dynamical interaction of the planets, which reside near a 3:1 mean-motion resonance. We modeled the TOI-6695 system's orbital and dynamical configuration by performing self-consistent N-body fits of TESS photometry, ground-based photometry from Observatoire Moana, and precise RV data, all of which are consistent with the presence of a warm Jovian-mass duo of exoplanets. *Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere under MPG programmes 0100.A-9007(A), 0104.A-9007(A), 0108.A-9003(A), 0109.A-9003(A), 105.20GX.001 (PI Brahm), 105.20L0.001 (PI Bouchy), 106.21ER.001 (PI Brahm),106.21TJ.001 (PI Gandolfi), 108.22A8.001 (PI Brahm), 109.239V.001 (PI Brahm), 110.23YQ.001 (PI Brahm), and 112.25W1.001 (PI Brahm). This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Keywords: Exoplanet astronomy, Radial velocity, Transit photometry, Exoplanet detection methods
Validating the Orbital Periods of the Coolest TESS Planet Candidates. When an exoplanet passes in front of its host star, the resulting eclipse causes an observable decrease in stellar flux, and when multiple such transits are detected, the orbital period of the exoplanet can be determined. Over the past seven years NASA's Transiting Exoplanet Survey Satellite (TESS) has discovered thousands of potential planets by this method, mostly with short orbital periods, although some have longer reported values over 100 days. These long orbital periods, however, are not easy to confirm due to frequent lengthy data gaps. Here we show that while many of these long period candidates likely have periods much shorter than reported, there are some TESS candidates with long periods to be found in the data. These candidates generally only have two reported transits, but the periods of duo-transits like this, and even candidates with three or more transits can be confirmed if the data rules out all possible shorter period aliases. Using TESS data, we confirm long orbital periods for nine candidate planets, and present five others that are likely long period (P &gt; 100 days). Due to their long periods, these planets will also have relatively cool equilibrium temperatures. We present these TESS Objects of Interest, along with a variety of small corrections to other TESS orbital periods and three planet candidates with possible transit timing variations, with the goal of refining the TESS data set and enabling future research with respect to cool transiting planets.

Keywords: Transit photometry, Exoplanets
Spot Distribution and Evolution on Two New Active Binaries Discovered in the YNHK Survey. The study on active binaries can provide detailed insights to understand how binarity affects dynamo actions inside stellar interiors. Here we report two active eclipsing binaries, USNO-B1.0 0743-0306638 and 0763-0282368, discovered in the Yunnan–Hong Kong wide-field photometric (YNHK) survey. Both of the two systems are detached binaries and show spot activities, while USNO-B1.0 0763-0282368 is more close to its Roche lobe. By means of the Wilson–Devinney (WD) code, their photometric solutions are determined based on parts of the YNHK photometric light curves. Furthermore, the spot distribution and evolution are investigated using time series of the YNHK light curves from 2016 to 2023. The results show that the spot activities appeared on the primary components for the two binary systems. There exist two kinds of spots: one is polar spots that lead to the variation of overall luminosity of the binaries, while the other is low-latitude spots that cause the rotational modulation. The polar spots behave more long-lived than the low-latitude spots on both binaries. For the low-latitude spot, its longitudinal distribution becomes more stable and closer to the substellar point as the binary system is close to the Roche lobe.

Keywords: Eclipsing binary stars, Starspots, Stellar activity
Stellar Populations and Molecular Gas Composition in the Low-metallicity Environment of WLM. We investigate the stellar populations and molecular gas properties of a star-forming region within the dwarf irregular (dIrr) galaxy Wolf─Lundmark─Mellote (WLM). Low-metallicity dIrrs like WLM offer a valuable window into star formation in environments that are unlike those of larger, metal-rich galaxies such as the Milky Way. In these conditions, carbon monoxide (CO), typically used to trace molecular clouds, is more easily photodissociated by ultraviolet (UV) radiation, leading to a larger fraction of CO-dark molecular gas, where H2 exists without detectable CO emission, or CO-dark gas in the form of cold H I. Understanding the molecular gas content and the stellar populations in these star-forming regions provides important information about the role of CO-bright and CO-dark gas in forming stars. Using Hubble Space Telescope imaging across five Wide Field Camera 3 UVIS bands and CO observations from the Atacama Large Millimeter Array, we examine stellar populations within and outside CO cores and the photodissociation region. Our findings indicate similar physical characteristics such as age and mass across the different environments. Assuming 2% of molecular gas is converted to stars, we estimate the molecular gas content and determine that CO-dark gas constitutes a large fraction of the molecular reservoir in WLM. These results are consistent with molecular gas estimates using a previous dust-derived CO-to-H2 conversion factor (αCO) for WLM. These findings highlight the critical role of CO-dark gas in low-metallicity star formation.

Keywords: Local Group, Dwarf irregular galaxies, Stellar populations, Star forming regions, Star formation
EFTE-SOAR: Two Giant M Dwarf Flares with Rapid Spectroscopic Follow-up. We present time-series optical spectroscopy of two stellar flares with complex multi-peaked light curves: a   erg flare from an M8 ultra-cool dwarf, and a   erg superflare from an M4 field star. Both flares were discovered by the Evryscope Fast Transient Engine and observed with the Southern Astrophysical Research 4.1 m telescope ∼10 minutes after their initial peak. We model the blackbody temperature of the flares as a function of time, finding that the characteristic temperature reaches ∼13,000 K during the secondary peaks of both events and is likely higher during the initial, unobserved impulsive phase. Both nonthermal emission from the near-UV Balmer continuum and an evolving red continuum of uncertain origin are observed in both flares; we compare the relative contributions of the continua, line emission, and blackbody component as the flare evolves, and find that the secondary peak of the M4 superflare immediately follows inversion of the relative contributions of the Balmer and red continua. We additionally present a model that constrains the evolution of the electron density of the stellar chromosphere during the flare, based on the time evolution of the observed red continuum excess, which we interpret as components of the hydrogen recombination continuum. Our observations of a 10.5 mag flare from an M8 dwarf, as well as a similar, unusually energetic event from an M4 dwarf, are comparable in intensity to the most energetic stellar flares reported in the literature to date.

Keywords: Spectroscopy, Stellar flares, Wide-field telescopes, Stellar activity
Keck and Gemini Characterization of Hayabusa2# Rendezvous Target 1998 KY<SUB>26</SUB>. Near-Earth object (NEO) 1998 KY26 is a target of the Hayabusa2# spacecraft, which it will rendezvous with in 2031 July. The asteroid has been noted to rotate rapidly and has a large out-of-plane nongravitational acceleration. We present observations consisting of deep-g- and R-band imaging obtained with the Keck I/Low Resolution Imaging Spectrometer (LRIS) and visible spectroscopy from Gemini North/Gemini Multi-Object Spectrograph (GMOS) taken of 1998 KY26 on 2024 June 8─9 when the asteroid was ∼0.037 au from the Earth. The asteroid does not show evidence of a dust coma and has a surface brightness profile similar to nearby background stars in the deep images. The spectrum of 1998 KY26 from the combined LRIS and GMOS observations most closely resembles Xe-type asteroids, possessing a spectral slope of 6.71% ± 0.43% 100 nm−1, and color indices g ─ r = 0.63 ± 0.03, r ─ i = 0.15 ± 0.03, i ─ z = 0.05 ± 0.04, and implies a diameter of ∼10 m. From our deep image stacks, we compute a 3σ upper limit on the dust production of 1998 KY26 of &lt;10−5 kg s−1, &lt;10−2 kg s−1, and &lt;10−1 kg s−1 assuming μm, mm, and cm size dust particles. In addition, we compare the orbit of 1998 KY26 and other known asteroids with large nongravitational parameters to NEO population models and find that the majority, including 1998 KY26, likely originated from the inner Main Belt, while the second most numerous group originates from the outer main belt, followed by a third group possibly originating from the Jupiter Family Comet population. Given its inner Main Belt origin, its Xe-type spectrum, and rapid rotation, we hypothesize that the nongravitational acceleration of 1998 KY26 may be caused by the shedding of large dust grains from its surface due to its rotation rather than H2O vapor outgassing.

Keywords: Near-Earth objects, Asteroid surfaces
Real-time Light Curve Classification Framework for the Wide Field Survey Telescope Using Modified Semisupervised Variational Autoencoder. Modern time-domain astronomy will benefit from the vast data collected by survey telescopes. The 2.5 m Wide Field Survey Telescope (WFST), with its powerful capabilities, is promising to make significant contributions in the era of large sky surveys. To harness the full potential of the enormous amount of unlabeled light curve data that the WFST will collect, we have developed a semisupervised light curve classification framework. This framework showcases several unique features. First, it is optimized for classifying events based on the early phase of the light curve (three days after trigger), which can help identify interesting events early and enable efficient follow-up observations. Second, the semisupervised nature of our framework allows it to leverage valuable information from large volumes of unlabeled data, potentially bridging the gap between simulations and real observations and achieving better generalization in practical scenarios. Compared to the commonly used Recurrent Neural Network models, our framework has shown a 5.59% improvement in accuracy for early classification tasks, as well as improvements in precision and recall in almost all subclasses. Moreover, our approach provides a reconstructed light curve, along with a compact latent representation, offering a different perspective that can be used for further downstream tasks beyond classification. The code and model weights used in this work are maintained and publicly available on our GitHub repository.

Keywords: Sky surveys, Light curve classification , Neural networks, Transient sources, Time series analysis
Photometry of Outer Solar System Objects from the Dark Energy Survey. II. A Joint Analysis of Trans-Neptunian Absolute Magnitudes, Colors, Light Curves and Dynamics. For the 696 trans-Neptunian objects (TNOs) with absolute magnitudes 5.5 &lt; Hr &lt; 8.2 detected in the Dark Energy Survey, we characterize the relationships between their dynamical state and physical properties—namely Hr, indicating size; colors, indicating surface composition; and flux variation semiamplitude A, indicating asphericity and surface inhomogeneity. We seek "birth" physical distributions that can recreate these parameters in every dynamical class. We show that the observed colors of these TNOs are consistent with two Gaussian distributions in griz space, "near-infrared bright" (NIRB) and "near-infrared faint" (NIRF), presumably an inner and outer birth population, respectively. We find a model in which both the NIRB and NIRF Hr and A distributions are independent of current dynamical states, supporting their assignment as birth populations. All objects are consistent with a common rolling p(Hr), but NIRF objects are significantly more variable. Cold classicals (CCs) are purely NIRF, while hot classical (HC), scattered, and detached TNOs are consistent with ≈ 70% NIRB and the resonance NIRB fractions show significant variation. The NIRB components of the HCs and of some resonances have broader inclination distributions than the NIRFs, i.e. their current dynamics retains information about birth location. We find evidence for radial stratification within the birth NIRB population, in that HC NIRBs are on average redder than detached or scattered NIRBs; a similar effect distinguishes CCs from other NIRFs. We estimate total object counts and masses of each class within our Hr range. These results will strongly constrain models of the outer solar system.

Keywords: Gaussian mixture model, Bayesian statistics, Kuiper belt, Trans-Neptunian objects
The Hubble Image Similarity Project. We have created a large database of similarity information between subregions of Hubble Space Telescope images. These data can be used to assess the accuracy of image-search algorithms based on computer vision methods. The images were compared by humans in a citizen science project, where they were asked to select similar images from a comparison sample. We utilized the Amazon Mechanical Turk system to pay our reviewers a fair wage for their work. Nearly 850,000 comparison measurements have been analyzed to construct a similarity distance matrix between all the pairs of images. We describe the algorithm used to extract a robust distance matrix from the (sometimes noisy) user reviews. The results are very impressive: The data capture similarity between images based on morphology, texture, and other details that are sometimes difficult even to describe in words (e.g., dusty absorption bands with sharp edges). The collective visual wisdom of our citizen scientists matches the accuracy of the trained eye, with even subtle differences among images faithfully reflected in the distances.

Keywords: Galaxies, Astronomy databases, Astronomy data analysis, Galaxy classification systems, Nebulae, Astronomy image processing, Star clusters
A Deep Search for Complex Organic Molecules toward the Protoplanetary Disk of V883 Ori. Complex organic molecules (COMs) in the form of prebiotic molecules are potential building blocks of life. Using Atacama Large Millimeter/submillimeter Array Band 7 observations in spectral scanning mode, we carried out a deep search for COMs within the disk of V883 Ori, covering a frequency range of ∼348–366 GHz. V883 Ori is an FU Orionis object currently undergoing an accretion burst, which increases its luminosity and consequently increases the temperature of the surrounding protoplanetary disk, facilitating the detection of COMs in the gas phase. We identify 26 molecules, including 14 COMs and 12 other molecules, with first detection in this source of the molecules CH3OD, H2C17O, and  . We searched for multiple nitrogen-bearing COMs, as   was the only N-bearing COM that had been identified so far in this source. We also detect  , and tentatively detect CH3CH2CN,  , CH3NCO, and NH2CHO. We compare the abundances relative to methanol (CH3OH) with those in the handful of objects with previous detections of these species: the Class 0 protostars IRAS 16293-2422 A, IRAS 16293-2422 B, and B1-c; the high-mass star-forming region Sagittarius B2 (North) (Sgr B2(N)); the solar system comet 67P/Churyumov-Gerasimenko (67P/C-G); and the protoplanetary disk of Oph-IRS 48. We report ∼1–3 orders of magnitude higher abundances compared to Class 0 protostars and ∼1–3 orders of magnitude lower abundances compared to the protoplanetary disk, Sgr B2(N), and 67P/C-G. These results indicate that the protoplanetary disk phase could contribute to the buildup of COMs.

Keywords: Protoplanetary disks, FU Orionis stars, Complex organic molecules, Pre-biotic astrochemistry
Wide Binary Orbits Are Preferentially Aligned with the Orbits of Small Planets, but Probably Not Hot Jupiters. Studying the relative orientations of the orbits of exoplanets and wide-orbiting binary companions (semimajor axis greater than 100 au) can shed light on how planets form and evolve in binary systems. Previous observations by multiple groups discovered a possible alignment between the orbits of visual binaries and the exoplanets that reside in them. In this study, using data from Gaia DR3 and TESS, we confirm the existence of an alignment between the orbits of small planets (R &lt; 6 R⊕) and binary systems with semimajor axes below 700 au (p = 10‑6). However, we find no statistical evidence for alignment between planet and binary orbits for binary semimajor axes greater than 700 au and no evidence for alignment of large, closely orbiting planets (mostly hot Jupiters) and binaries at any separation. The lack of orbital alignment between our large-planet sample and their binary companions appears significantly different from our small-planet sample, even taking into account selection effects. Therefore, we conclude that any alignment between wide binaries and our sample of large planets (predominantly hot Jupiters) is probably not as strong as what we observe for small planets in binaries with semimajor axes less than 700 au. The difference in the alignment distribution of hot Jupiters and smaller planets may be attributed to the unique evolutionary mechanisms occurring in systems that form hot Jupiters, including potentially destabilizing secular resonances that initiate as the protoplanetary disk dissipates and high-eccentricity migration occurring after the disk is gone.

Keywords: Star-planet interactions
Search for the Blazhko Effect in Field RR Lyrae Stars Using LINEAR and ZTF Light Curves. We analyzed the incidence and properties of RR Lyrae stars that show evidence for amplitude and phase modulation (the so-called Blazhko Effect) in a sample of ∼3000 stars with LINEAR and ZTF light curve data collected during the periods of 2002–2008 and 2018–2023, respectively. A preliminary subsample of about ∼500 stars was algorithmically preselected using various data quality and light curve statistics, and then 228 stars were confirmed visually as displaying the Blazhko effect. This sample increases the number of field RR Lyrae stars displaying the Blazhko effect by more than 50% and places a lower limit of (11.4 ± 0.8)% for their incidence rate. We find that ab type RR Lyrae that show the Blazhko effect have about 5% (0.030 day) shorter periods than starting sample, a 7.1σ statistically significant difference. We find no significant differences in their light curve amplitudes and apparent magnitude (essentially, signal-to-noise ratio) distributions. No period or other differences are found for c type RR Lyrae. We find convincing examples of stars where the Blazhko effect can appear and disappear on timescales of several years. With time-resolved photometry expected from the Legacy Survey of Space and Time, a similar analysis will be performed for even larger samples of field RR Lyrae stars in the southern sky and we anticipate a higher fraction of discovered Blazhko stars due to better sampling and superior photometric quality.

Keywords: RR Lyrae variable stars