Sazuna/UAT_keywords huggingface dataset:
The Spin─Orbit Alignment of Eight Warm Gas Giant Systems. Essential information about the formation and evolution of planetary systems can be found in their architectures—in particular, in stellar obliquity (ψ)—as they serve as a signature of their dynamical evolution. Here we present ESPRESSO observations of the Rossiter─McLaughlin (RM) effect of eight warm gas giants, revealing that, independently of the eccentricities, all of them have relatively aligned orbits. Our five warm Jupiters (WASP-106 b, WASP-130 b, TOI-558 b, TOI-4515 b, and TOI-5027 b) have sky-projected obliquities ∣λ∣ ≃ 0─10 °, while the two less massive warm Saturns (K2-139 b and K2-329 A b) are slightly misaligned, having ∣λ∣ ≃ 15─25 °. Furthermore, for K2-139 b, K2-329 A b, and TOI-4515 b, we also measure true 3D obliquities ψ ≃ 15─30 °. We also report a nondetection of the RM effect produced by TOI-2179 b. Through hierarchical Bayesian modeling of the true 3D obliquities of hot and warm Jupiters, we find that around single stars warm Jupiters are statistically more aligned than hot Jupiters. Independent of eccentricities, 95% of the warm Jupiters have ψ ≲ 25 ° with no misaligned planets, while hot Jupiters show an almost isotropic distribution of misaligned systems. This implies that around single stars warm Jupiters form in primordially aligned protoplanetary disks and subsequently evolve in a more quiescent way than hot Jupiters. Finally, we find that Saturns may have slightly more misaligned orbits than warm Jupiters, but more obliquity measurements are necessary to be conclusive. *Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programs ID 108.22C0, 109.238M, 110.23Y8, and 113.26KH.

Keywords: Exoplanet dynamics, Exoplanet migration, Exoplanets, Planetary alignment, Exoplanet systems
No Influence of Passing Stars on Paleoclimate Reconstructions Over the Past 56 Million Years. Passing stars (also called stellar flybys) have notable effects on the solar system's long-term dynamical evolution, injection of Oort cloud comets into the solar system, properties of trans-Neptunian objects, and more. Based on a simplified solar system model, omitting the Moon and the Sun's quadrupole moment J2, it has recently been suggested that passing stars are also an important driver of paleoclimate before ∼50 Myr ago, including a climate event called the Paleocene-Eocene Thermal Maximum (∼56 Myr ago). In contrast, using a state-of-the-art solar system model, including a lunar contribution and J2, and random stellar parameters (&gt;400 simulations), we find no influence of passing stars on paleoclimate reconstructions over the past 56 Myr. Even in an extreme flyby scenario in which the Sun-like star HD 7977 (m = 1.07M⊙) would have passed within ∼3900 au about 2.8 Myr ago (with 5% likelihood), we detect no discernible change in Earth's orbital evolution over the past 70 Myr, compared to our standard model. Our results indicate that a complete physics model is essential to accurately study the effects of stellar flybys on Earth's orbital evolution.

Keywords: Celestial mechanics, Orbits, Solar system, Solar neighborhood
Accelerating Stellar Photometric Distance Estimates with Neural Networks. Building on the Bayesian approach to estimating stellar distances from broadband photometry, we show that the computation can be accelerated by about an order of magnitude by using neural networks. Focusing on the case of the ugrizy filter complement for Rubin's Legacy Survey of Space and Time (LSST), we show that the Bayesian approach is equivalent to mapping from a 10-dimensional space of five measured colors and their uncertainties to a three-dimensional space of absolute magnitude, metallicity, and interstellar dust extinction along the line of sight. Once the neural network is trained, this mapping is faster by more than an order of magnitude compared to the Bayesian approach, for both optimized grid search and Markov chain Monte Carlo implementation methods. We have developed and tested a pipeline that achieves significant acceleration by first running the Bayesian method on 5%–10% of the sample, then using it to train a neural network, and finally processing the entire sample with the resulting neural network. This computation is done in patches of about 10 deg2 due to the variation of Bayesian priors across the sky. We present an analysis of pipeline performance, including speed and biases as functions of input stellar parameters and signal-to-noise ratio, using TRILEGAL-based simulated LSST catalogs by P. Dal Tio et al. We intend to run this pipeline on LSST data releases and make its outputs publicly available.

Keywords: Neural networks, Distance measure, Distance indicators, Reddening law, Extinction, Interstellar extinction, Stellar distance
DART-Vetter: A Deep Learning Tool for Automatic Triage of Exoplanet Candidates. In the identification of new planetary candidates in transit surveys, the employment of deep learning models proved to be essential to efficiently analyze a continuously growing volume of photometric observations. To further improve the robustness of these models, it is necessary to exploit the complementarity of data collected from different transit surveys such as NASA's Kepler, Transiting Exoplanet Survey Satellite (TESS), and, in the near future, the ESA Planetary Transits and Oscillation of stars mission. In this work, we present a deep learning model, named DART-Vetter, that is able to distinguish planetary candidates from false positives signals detected by any potential transiting survey. DART-Vetter is a convolutional neural network that processes only the light curves folded on the period of the relative signal, featuring a simpler and more compact architecture with respect to other triaging and/or vetting models available in the literature. We trained and tested DART-Vetter on several data sets of publicly available and homogeneously labelled TESS and Kepler light curves in order to prove the effectiveness of our model. Despite its simplicity, DART-Vetter achieves highly competitive triaging performance, with a recall rate of 91% on an ensemble of TESS and Kepler data, when compared to Exominer and Astronet-Triage. Its compact, open source, and easy to replicate architecture makes DART-Vetter a particularly useful tool for automatizing triaging procedures or assisting human vetters, showing a discrete generalization on threshold-crossing events with multiple event statistic &gt; 20 and orbital period &lt; 50 days.

Keywords: Exoplanet detection methods, Convolutional neural networks, Astronomy data analysis
The Chemical Clock of High-mass Star-forming Regions: N<SUB>2</SUB>H<SUP>+</SUP>/CCS. Using the Institut de Radioastronomie Millmétrique 30 m telescope, we presented observations of N2H+ J = 1‑0, CCS JN = 87–76 and 77–66 lines toward a large sample of ultracompact H II regions (UC H IIs). Among our 88 UC H IIs, 87 and 33 sources were detected in the N2H+ J = 1‑0 and CCS JN = 87–76 lines, respectively. For the CCS 77–66 transition, we detected emission in 10 out of 82 targeted sources, all of which also exhibited emission in the CCS JN = 87–76 line. Physical parameters are derived for our detections, including the optical depth and excitation temperature of N2H+, the rotational temperature of CCS and the column density. Combining our results and previous observation results in different stages of high-mass star-forming regions (HMSFRs), we found that the column density ratio N(N2H+)/N(CCS) increases from high-mass starless cores through high-mass protostellar cores to UC H IIs. This implies that N(N2H+)/N(CCS) can trace the evolution process of HMSFRs. It was supported by our gas-grain chemical model, which shows that N(N2H+)/N(CCS) increases with the evolution age of HMSFRs. The temperature, density and chemical age were also constrained from our best-fit model at each stage. Thus, we propose N(N2H+)/N(CCS) as a reliable chemical clock of HMSFRs.

Keywords: Massive stars, Chemical abundances, Abundance ratios, Astrochemistry
KMT-2022-BLG-0086: Another Binary-lens Binary-source Microlensing Event. We present the analysis of a microlensing event KMT-2022-BLG-0086 of which the overall light curve is not described by a binary-lens single-source (2L1S) model, which suggests the existence of an extra lens or an extra source. We found that the event is best explained by the binary-lens binary-source (2L2S) model, but the 2L2S model is only favored over the triple-lens single-source (3L1S) model by Δχ2 ≃ 9. Although the event has noticeable anomalies around the peak of the light curve, they are not enough covered to constrain the angular Einstein radius θE, thus we only measure the minimum angular Einstein radius  θE,min . From the Bayesian analysis, it is found that that the binary lens system is a binary star with masses of  (m1,m2)=(0.46‑0.25+0.35M⊙,0.75‑0.55+0.67M⊙)  at a distance of  DL=5.87‑1.79+1.21  kpc, while the triple lens system is a brown dwarf or a massive giant planet in a low-mass binary-star system with masses of  (m1,m2,m3)=(0.43‑0.35+0.41M⊙,0.056‑0.047+0.055M⊙ ,  20.84‑17.04+20.20MJ)  at a distance of  DL=4.06‑3.28+1.39  kpc, indicating a disk lens system. The 2L2S model yields the relative lens-source proper motion of μrel ≥ 4.6 mas yr‑1 that is consistent with the Bayesian result, whereas the 3L1S model yields μrel ≥ 18.9 mas yr‑1, which is more than three times larger than that of a typical disk object of ∼6 mas yr‑1 and thus is not consistent with the Bayesian result. This suggests that the event is likely caused by the binary-lens binary-source model.

Keywords: Gravitational microlensing
Ultradeep Imaging of Nearby Dwarf Irregular Galaxies: Young Objects in the Far Outer Disk. Ultradeep UBVI imaging of 10 nearby (≤7.8 Mpc) noninteracting dwarf irregular galaxies are used to examine their far outer stellar disks. The annulus between 26 mag arcsec‑2 and 29 mag arcsec‑2 in the V band is what we define as the far outer disk and is our focus here. Photometry of distinct objects in the far outer disks, including far-UV images, is used to determine ages of the objects in order to look for those that are young. In three of the galaxies we find objects with high-confidence ages ≤30 Myr. These objects are too young to have scattered into the far outer disk from the central regions. Therefore, they likely formed in situ. How star-forming gas clouds formed in the extreme environment of the outer stellar disks of dwarfs is a primary unanswered question.

Keywords: Dwarf irregular galaxies, Star formation, Galaxy evolution
The Fraction of Polar-aligned Circumbinary Disks. Circumbinary gas disks that are misaligned to the binary orbital plane evolve toward either a coplanar or a polar-aligned configuration with respect to the binary host. The preferred alignment depends on the dynamics of the disk: whether it undergoes librating or circulating nodal precession, with librating disks evolving to polar inclinations and circulating disks evolving to coplanar. We quantify the fraction of binary star systems whose disks are expected to have polar orbits fpolar, extending previous work to include disks with nonzero mass. Our results suggest that, for low mass disks, the polar fraction is highly sensitive to the distribution of binary eccentricity, with a higher fraction expected for higher binary eccentricities, fpolar ∼ eb. However, for massive disks, the fraction is independent of the binary eccentricity and fpolar ≍ 0.37. The value of fpolar is always reduced in a population with a greater preference for low initial mutual inclination. We also explore the consequences of the finite lifetime and nonzero radial extent of a real disk, both of which affect a disk's ability to complete its evolution to a stationary configuration. Our findings can be used to make predictions given populations with well-understood distributions of binary eccentricity, initial mutual inclination, and disk angular momentum.

Keywords: Stellar accretion disks, Binary stars, N-body simulations
Two More Bow Shocks and Off-center Hα Nebulae Associated with Nova-like Cataclysmic Variables. We report discoveries of bow-shock nebulae, seen in Hα and [O III] λ5007, around two cataclysmic variables (CVs): LS Pegasi and ASASSN-V J205457.73+515731.9 (ASASJ2054). Additionally, both stars lie near the edges of faint extended Hα-emitting nebulae. The orientations of the bow shocks are consistent with the directions of the objects' proper motions. The properties of LS Peg and ASASJ2054, and of their nebulae, are remarkably similar to those of SY Cancri (SY Cnc), which we described in a recent paper; SY Cnc is a CV likewise associated with a bow shock and an off-center Hα nebula. These objects join V341 Arae and BZ Camelopardalis, CVs that are also accompanied by similar nebulae. All five stars belong to the nova-like variable (NLV) subclass of CVs, characterized by luminous optically thick accretion disks that launch fast winds into the surrounding space. We suggest that the bow shocks and nebulae result from chance encounters of the NLVs with interstellar gas clouds, with the stars leaving in their wakes Strömgren zones that are recombining after being photoionized by the CVs' ultraviolet and X-ray radiation. Our discoveries illustrate the power of small telescopes equipped with modern instrumentation, and used to accumulate extremely long exposure times, for the detection of very low-surface-brightness nebulae. ∗Based in part 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-Universität München, and Georg-August Universität Göttingen. The HET is named in honor of its principal benefactors, William P. Hobby and Robert E. Eberly.

Keywords: Stellar bow shocks, Dwarf novae, Emission nebulae, Nova-like variable stars, Cataclysmic variable stars, Classical novae, VY Sculptoris stars
Continued Photometric Monitoring Supports Long-term Dynamical Evolution in the Young Binary Star–Disk System KH 15D. We present photometric time series data spanning 2018–2024 that show the effects of temporal dynamics in the binary system KH 15D, a member of the NGC 2264 star-forming region. This source exhibits complex eclipsing behavior due to a precessing circumbinary disk or ring that is slightly inclined relative to the orbital plane of the binary. Using g-band and r-band observations from the Zwicky Transient Facility over seven observing seasons, we follow the evolution of the KH 15D lightcurve as it continues to emerge from its deepest observed photometric minimum about 15 yr ago. Our observations are consistent with previous models that propose a precessing, warped circumbinary disk orbiting KH 15D. We verify the gradual precession of the disk by quantifying the times of eclipse ingresses and egresses. We also examine the central rebrightening within the minima of the phased lightcurve. This feature has increased in amplitude over our observing seasons, and we measure its evolution in both amplitude and phase from year to year. Finally, we assess color as a function of phase and brightness. Our findings support the assertion that line-of-sight variations in disk density and structure, possibly due to clumping, coupled with a precessing circumbinary disk are responsible for the central rebrightening event.

Keywords: Binary stars, Light curves, Young stellar objects, Pre-main sequence stars, Occulting disks
Acceleration of C IV and Si IV Broad Absorption Lines in Quasar SDSS J140058.79+260619.4. We report the discovery of a velocity shift signature in the C IV and Si IV broad absorption lines (BALs) of the quasar SDSS J140058.79+260619.4 (zem = 2.351). From its two-epoch spectra, we find two BAL systems (systems A and B) in C IV and/or Si IV ions. Firstly, we find obvious variations of equivalent widths across all BAL troughs, which are most plausibly explained by changes in ionization states. Secondly, system A, characterized by a higher velocity and smoother profile shape (than those of System B), shows significant velocity shifts in C IV and Si IV BALs between two epochs, indicating potential outflow accelerations. Over 1.83 yr in the rest frame, we measure velocity differences of ‑481 ± 64 km s‑1 for C IV and ‑550 ± 95 km s‑1 for Si IV, corresponding to acceleration rates of ‑0.83 ± 0.11 cm s‑2 and ‑0.95 ± 0.17 cm s‑2, respectively. Given the limited observational data, the physical origin of this velocity shift signature remains an open question. We considered several plausible mechanisms, favoring either variations in the gas's ionization state or actual line-of-sight acceleration driven by radiation pressure from the central source.

Keywords: Quasars, Quasar absorption line spectroscopy, Broad-absorption line quasar
Planetesimal Scattering Efficiency of Cold Giant Planet Architectures. The discovery of many exoplanets has revealed an incredible diversity of orbital architectures. These orbital configurations are intrinsically linked to the potential for habitable environments within the system, since the gravitational influence of the planets governs the angular momentum distribution within the system. This angular momentum distribution in turn alters the planetary orbits and rotational obliquities. In the case of giant planets, their gravitational influence can also produce significant redistribution of volatiles, particularly those that lie beyond the snow line. Here, we present the results of dynamical simulations that investigate the role of cold giant planets in scattering material to inner terrestrial planets. We highlight 10 exoplanetary systems with two or more known giant planets beyond the snow line, and adopt a solar system analog template that investigates the scattering of material within the range 3–8 au. We show that increasing the eccentricity of a Jupiter analog from its present, near-circular value to a moderate range (0.2–0.3) results in an order of magnitude increase in scattered material to the inner part of the system. The inclusion of a Saturn analog to the dynamical model produces a similar increase, highlighting the importance of multiple giant planets beyond the snow line. However, the addition of analogs to Uranus and Neptune can have a minor negative effect on scattering efficiency through the transfer of angular momentum from the inner giant planets.

Keywords: Exoplanet dynamics, Exoplanets, Orbits, Solar system, Exoplanet systems, Orbital evolution, Solar system gas giant planets, Solar system terrestrial planets, Exoplanet evolution, Solar system evolution, Habitable zone, Habitable planets
Thermal and Optical Characterization of Near-Earth Objects: Science Commissioning of the Recently Upgraded Mid-infrared Camera MIRSI on the NASA Infrared Telescope Facility. Mid-infrared (mid-IR) observations of near-Earth objects (NEOs) have historically been a valuable tool for understanding their physical properties. However, the current state of mid-IR instruments on ground-based telescopes places several limitations on performing thermal characterization of NEOs. The complexity of maintaining these instruments in operational conditions on telescopes has led to their decommissioning. Here, we present the first science commissioning observations out to 12.5 μm from the upgraded Mid-Infrared Spectrograph and Imager (MIRSI) at the NASA-IRTF. We obtained 42 observations of 31 NEOs and derived their diameters and albedos. Since MIRSI allows for simultaneous optical observations with its MIRSI Optical Camera, we were able to determine the absolute magnitude for most of the targets at the time of the thermal acquisition. We present ejecta characterization for the Didymos system from observations made 11 hr and 9 days after the Double Asteroid Redirection Test impact. We present albedo and size measurements for (98943) Torifune 2001 CC21, the fly-by target of the Japanese Extended Hayabusa2 Mission. We also highlight several applications that the MIRSI system will provide for future airless body characterization, such as constraining thermal inertia from simultaneous optical and thermal lightcurves. This work also demonstrates the importance of having MIRSI as an available rapid-response instrument for planetary defense purposes.

Keywords: Observational astronomy, Near-Earth objects, Small Solar System bodies, Astronomical instrumentation, Spectral energy distribution, Photometry
Binary Star Orbits. VI. The Interferometric-spectroscopic Binary 73 Leo. Discordances in radial-velocity measurements of 73 Leonis, made more than a century ago, gave rise to the first suggestion that this fifth-magnitude star was a binary system, but it was 40 yr before an accurate investigation of the object commenced, and a further 25 yr (close to three orbital cycles) before R. F. Griffin's new velocities, combined with older ones, yielded a high-quality orbit. However, a few years earlier the system had been resolved astrometrically by speckle interferometry, so a combined solution was attempted that yielded a very precise period (σ ∼ 0.1%P, primarily on the strength of the precision of the radial-velocities), with a less-well determined semimajor axis (σ ∼ 2.4%a″). Nonetheless 73 Leo continued to present a challenge to astrometric and photometric techniques alike, and also to spectroscopic classification and stellar-evolution theory. Now, with the superior resolution capability of the Navy Precision Optical Interferometer and new radial-velocity data from the Dominion Astrophysical Observatory high-resolution spectrograph, those uncertainties have been reduced to 0.02% in P and 0.15% in a″. This paper describes the new data acquired since 1997, and reports our new attempts to parameterize the system (including the spectral type of the secondary) by appealing to very recent photometry. Notwithstanding, direct spectroscopic evidence of the secondary component is little more than suggestive, so a complete SB2 solution yielding an orbital parallax and limits to the masses of the component stars remains elusive.

Keywords: Spectroscopic binary stars, Interferometric binary stars, Binary stars
Survey of Oxygen-rich AGB Stars Using the KVN 4 Receiving Bands—SMASTES. I.. Simultaneous observations of 19 H2O and SiO maser and thermal lines were performed toward 155 M-type oxygen-rich (O-rich) AGB stars. We used the upgraded four-band (22/43/86/129 GHz) wide receiving system of the Korean VLBI Network (KVN). The 155 O-rich stars composed of 50 semiregulars (SRs), 55 Miras, and 50 OH/IR stars were selected based on previous KVN H2O/SiO detected sources. Both H2O and SiO masers were detected in 23 stars among 50 SRs, 50 stars among 55 Miras, and 24 stars among 50 OH/IRs, respectively. Out of 50 SRs, H2O-only masers, without corresponding SiO maser detection, were observed in four stars. In contrast, no H2O-only masers were detected in any of the 55 Mira or 50 OH/IR stars, which differs from the pattern seen with SiO-only masers. Interestingly, in the 50 SRs, the SiO v = 1, J = 2─1 maser was detected more than the SiO v = 1, J = 1─0 maser despite requiring a higher excitation energy. The 28SiO v = 0, J = 1─0, 2─1, 3─2 lines were detected more frequently at higher rotational transitions, especially in the SRs and Miras. The HCN and SiS were detected from 11 and 3 stars, respectively. For our observational results, we performed statistical analysis on the intensity ratio variations among H2O and various SiO masers, chemical environments, and wind kinematics. The characteristics of these property variations were investigated in the IRAS two-color diagram in relation to their evolutionary stages.

Keywords: Interstellar thermal emission, Asymptotic giant branch stars, Astrophysical masers, Late stellar evolution