Sazuna/UAT_keywords huggingface dataset:
Evidence for the Disruption of a Planetary System During the Formation of the Helix Nebula. The persistence of planetary systems after their host stars evolve into their post-main-sequence phase is poorly constrained by observations. Many young white dwarf systems exhibit infrared excess emission and/or spectral absorption lines associated with a reservoir of dust (or planetesimals) and its accretion. However, most white dwarfs are too cool to sufficiently heat any circumstellar dust to detectable levels of emission. The Helix Nebula (NGC 7293) is a young, nearby planetary nebula; observations at mid- and far-infrared wavelengths have revealed excess emission associated with its central white dwarf (WD 2226-210). The origin of this excess is ambiguous. It could be a remnant planetesimal belt, a cloud of comets, or the remnants of material shed during the post-asymptotic giant branch (post-AGB) phase. Here we combine infrared (Stratospheric Observatory for Infrared Astronomy, Spitzer, Herschel) and millimeter (Atacama Large Millimeter/submillimeter Array) observations of the system to determine the origin of this excess using multiwavelength imaging and radiative transfer modeling. We find the data are incompatible with a compact remnant planetesimal belt or post-AGB disk, and conclude the dust most likely originates from deposition by a cometary cloud. The measured dust mass, and lifetime of the constituent grains, implies disruption of several thousand Hale-Bopp equivalent comets per year to fuel the observed excess emission around the Helix Nebula's white dwarf.

Keywords: Infrared excess, White dwarf stars, Circumstellar disks
Hazy with a Chance of Star Spots: Constraining the Atmosphere of Young Planet K2-33b. Although all-sky surveys have led to the discovery of dozens of young planets, little is known about their atmospheres. Here, we present multiwavelength transit data for the super-Neptune sized exoplanet, K2-33b-the youngest (~10 Myr) transiting exoplanet to date. We combined photometric observations of K2-33 covering a total of 33 transits spanning &gt;2 yr, taken from K2, MEarth, the Hubble Space Telescope (HST), and Spitzer. The transit photometry spanned from the optical to the near-infrared (0.6-4.5 μm), enabling us to construct a transmission spectrum of the planet. We find that the optical transit depths are nearly a factor of 2 deeper than those from the near-infrared. This difference holds across multiple data sets taken over years, ruling out issues of data analysis and unconstrained systematics. Surface inhomogeneities on the young star can reproduce some of the difference, but required spot coverage fractions (&gt;60%) are ruled out by the observed stellar spectrum (&lt;20%). We find a better fit to the transmission spectrum using photochemical hazes, which were predicted to be strong in young, moderate-temperature, and large-radius planets like K2-33b. A tholin haze with CO as the dominant gaseous carbon carrier in the atmosphere can reasonably reproduce the data with small or no stellar surface inhomogeneities, consistent with the stellar spectrum. The HST data quality is insufficient for the detection of any molecular features. More observations would be required to fully characterize the hazes and spot properties and confirm the presence of CO suggested by current data.

Keywords: M dwarf stars, Starspots, Exoplanet evolution, Markov chain Monte Carlo, Open star clusters, Transit photometry, Exoplanet atmospheres
The Sensitivity of Eclipse Mapping to Planetary Rotation. Mapping exoplanets across phases and during secondary eclipse is a powerful technique for characterizing Hot Jupiters in emission. Since these planets are expected to rotate about axes normal to their orbital planes, with rotation periods synchronized with their orbital periods, mapping provides a direct correspondence between the orbital phase and planetary longitude. We develop a framework to understand the information content of planets where their rotation states are not well constrained, by constructing bases of light curves across different rotation rates and obliquities that are orthogonal in integrated flux across the secondary eclipse. These demonstrate that brightness variation during eclipse may arise from a variety of rotation rates, obliquities, and map structures, requiring priors to properly disentangle each of these components. By modeling eclipse observations of the Warm Jupiter HAT-P-18b we demonstrate that, at a signal-to-noise equivalent to ~10 orbits with JWST, confusion about map structure is likely a concern only at the upper physical limits of possible rotation rates. Even without priors, one may nevertheless be able to put an order-of-magnitude constraint on rotation rate by determining at what rates the fitted map complexity is minimized, a prescription whose efficacy increases if out-of-eclipse data are available to isolate the effects of rotation. Finally, in the limit of maps with longitudinal symmetry, the projected obliquity in the plane of the sky determines the information available during eclipse, ranging from nondetections of structure to a basic constraint on hemispherical asymmetry and orientation depending on the obliquity angle.

Keywords: Exoplanet dynamics, Exoplanet structure, Exoplanet atmospheres
The PhotoDissociation Region Toolbox: Software and Models for Astrophysical Analysis. The PhotoDissociation Region Toolbox provides comprehensive, easy-to-use, public software tools and models that enable an understanding of the interaction of the light of young, luminous, massive stars with the gas and dust in the Milky Way and in other galaxies. It consists of an open-source Python toolkit and photodissociation region (PDR) models for analysis of infrared and millimeter/submillimeter line and continuum observations obtained by ground-based and suborbital telescopes, and astrophysics space missions. PDRs include all of the neutral gas in the interstellar medium where far-ultraviolet photons dominate the chemistry and/or heating. In regions of massive star formation, PDRs are created at the boundaries between the H II regions and neutral molecular cloud, as photons with energies 6 eV &lt; h ν &lt; 13.6 eV photodissociate molecules and photoionize metals. The gas is heated by photoelectrons from small grains and large molecules and cools mostly through far-infrared (FIR) fine-structure lines like [O I] and [C II]. The models are created from state-of-the art PDR codes that include molecular freeze-out; recent collision, chemical, and photorates; new chemical pathways, such as oxygen chemistry; and allow for both clumpy and uniform media. The models predict the emergent intensities of many spectral lines and FIR continuum. The tools find the best-fit models to the observations and provide insight into the physical conditions and chemical makeup of the gas and dust. The PDR Toolbox enables novel analysis of data from telescopes such as the Infrared Space Observatory, Spitzer, Herschel, the Stratospheric Terahertz Observatory, the Stratospheric Observatory for Infrared Astronomy, the Submillimeter Wave Astronomy Satellite, the Atacama Pathfinder Experiment, the Atacama Large Millimeter/submillimeter Array, and the JWST.

Keywords: Molecular gas, Astronomy software, Photodissociation regions, Interstellar atomic gas
Detection of Strongly Lensed Arcs in Galaxy Clusters with Transformers. Strong lensing in galaxy clusters probes properties of dense cores of dark matter halos in mass, studies the distant universe at flux levels and spatial resolutions otherwise unavailable, and constrains cosmological models independently. The next-generation large-scale sky imaging surveys are expected to discover thousands of cluster-scale strong lenses, which would lead to unprecedented opportunities for applying cluster-scale strong lenses to solve astrophysical and cosmological problems. However, the large data set challenges astronomers to identify and extract strong-lensing signals, particularly strongly lensed arcs, because of their complexity and variety. Hence, we propose a framework to detect cluster-scale strongly lensed arcs, which contains a transformer-based detection algorithm and an image simulation algorithm. We embed prior information of strongly lensed arcs at cluster scale into the training data through simulation and then train the detection algorithm with simulated images. We use the trained transformer to detect strongly lensed arcs from simulated and real data. Results show that our approach could achieve 99.63% accuracy rate, 90.32% recall rate, 85.37% precision rate, and 0.23% false-positive rate in detection of strongly lensed arcs from simulated images and could detect almost all strongly lensed arcs in real observation images. Besides, with an interpretation method, we have shown that our method could identify important information embedded in simulated data. Next, to test the reliability and usability of our approach, we will apply it to available observations (e.g., DESI Legacy Imaging Surveys 6 6 https://www.legacysurvey.org/ ) and simulated data of upcoming large-scale sky surveys, such as Euclid 7 7 https://www.euclid-ec.org/ and the China Space Station Telescope. 8 8 https://nao.cas.cn/csst/

Keywords: Strong gravitational lensing, Convolutional neural networks, Astronomy data analysis
Zonal Winds of Uranus and Neptune: Gravitational Harmonics, Dynamic Self-gravity, Shape, and Rotation. Uranus and Neptune exhibit fast surface zonal winds that can reach up to a few hundred meters per second. Previous studies on zonal gravitational harmonics and ohmic dissipation constraints suggest that the wind speeds diminish rapidly in relatively shallow depths within the planets. Through a case-by-case comparison between the missing dynamical gravitational harmonic ${J}_{4}^{{\prime} }$ from structure models, and with that expected from fluid perturbations, we put constraints on zonal wind decay in Uranus and Neptune. To this end, we generate polytropic empirical structure models of Uranus and Neptune using fourth-order theory of figures that leave hydrostatic J 4 as an open parameter. Allotting the missing dynamical contribution to density perturbations caused by zonal winds (and their dynamic self-gravity), we find that the maximum scale height of zonal winds are ~2%-3% of the planetary radii for both planets. Allowing the models to have J 2 solutions in the ±5 × 10-6 range around the observed value has similar implications. The effect of self-gravity on ${J}_{4}^{{\prime} }$ is roughly a factor of ten lower than that of zonal winds, as expected. The decay scale heights are virtually insensitive to the proposed modifications to the bulk rotation periods of Uranus and Neptune in the literature. Additionally, we find that the dynamical density perturbations due to zonal winds have a measurable impact on the shape of the planet, and could potentially be used to infer wind decay and bulk rotation period via future observations.

Keywords: Neptune, Planetary interior, Planetary dynamics, Uranus
M33 Cepheids from CFHT/MegaCam Survey. In this paper we analyze Sloan g, r, i archival imaging data of M33 taken by Hartman et al. using MegaCam at the Canada-France-Hawaii Telescope. To determine the distance to the M33 galaxy, we performed several analytical steps to identify its Cepheid population. We used the Lomb-Scargle algorithm to find periodicity and visually identified 1989 periodic variable stars. Since Cepheids occupy a specific region of the color-magnitude diagram, to differentiate Cepheids from other variables we used the expected position of the Cepheid instability strip to down-select Cepheids in M33 from other variables. This led to our sample of 1622 variables, the largest Cepheid sample known in M33 to date. We further classified these Cepheids into different subclasses, and used the fundamental mode Cepheids to estimate distance moduli for M33 in different filters: μ = 25.044 ± 0.083 mag in the g filter, μ = 24.886 ± 0.074 mag in the r filter, and μ = 24.785 ± 0.068 mag for the i filter. These results are in agreement with previous results.

Keywords: Triangulum Galaxy, Cepheid variable stars, Distance indicators
Deep Orbital Search for Additional Planets in the HR 8799 System. The HR 8799 system hosts four massive planets orbiting 15 and 80 au. Studies of the system's orbital stability and its outer debris disk open the possibility of additional planets, both interior to and exterior to the known system. Reaching a sufficient sensitivity to search for interior planets is very challenging due to the combination of bright quasi-static speckle noise close to the stellar diffraction core and relatively fast orbital motion. In this work, we present a deep L-band imaging campaign using NIRC2 at Keck comprising 14 observing sequences. We further re-reduce archival data for a total of 16.75 hr, one of the largest uniform data sets of a single direct imaging target. Using a Bayesian modeling technique for detecting planets in images while compensating for plausible orbital motion, we then present deep limits on the existence of additional planets in the HR 8799 system. The final combination shows a tentative candidate, consistent with 4-7 M jup at 4-5 au, detected with an equivalent false-alarm probability better than 3σ. This analysis technique is widely applicable to archival data and to new observations from upcoming missions that revisit targets at multiple epochs.

Keywords: Direct imaging, Exoplanets
The Eclipsing Binaries from the LAMOST Medium-resolution Survey. III. A High-precision Empirical Stellar Mass Library. High-precision stellar masses and radii measured directly from binaries can effectively calibrate stellar models. However, such a database containing full spectral types and a large range of metallicity is still not fully established. A continuous effort of data collection and analysis is requested to complete the database. In this work, we provide a catalog containing 184 binaries with independent atmospheric parameters and accurate masses and radii as the benchmark for stellar mass and radius. The catalog contains 56 new detached binaries from the LAMOST medium-resolution spectroscopic survey and 128 detached eclipsing binaries compiled from previous studies. We obtain the orbital solutions of the new detached binaries with uncertainties of masses and radii smaller than 5%. These new samples densify the distribution of metallicity of the high-precision stellar mass library and add nine hot stars with T eff &gt; 8000 K. Comparisons show that these samples agree well with the PARSEC isochrones in T eff-logg-mass-radius-luminosity space. We compare mass and radius estimates from isochrone and spectral energy distribution fitting, respectively, with those from the binary orbital solution. We find that the precision of the stellar-model-dependent mass estimates is &gt;10% and the precision of the radius estimates based on atmospheric parameters is &gt;15%. These give a general view of the uncertainty of the usual approaches to estimate stellar mass and radius.

Keywords: Astronomy databases, Astronomy data analysis, Detached binary stars, Stellar masses, Catalogs
Metallicity-PAH Relation of MIR-selected Star-forming Galaxies in AKARI North Ecliptic Pole-wide Survey. We investigate the variation in the mid-infrared spectral energy distributions of 373 low-redshift (z &lt; 0.4) star-forming galaxies, which reflects a variety of polycyclic aromatic hydrocarbon (PAH) emission features. The relative strength of PAH emission is parameterized as q PAH, which is defined as the mass fraction of PAH particles in the total dust mass. With the aid of continuous mid-infrared photometric data points covering 7-24 μm and far-infrared flux densities, q PAH values are derived through spectral energy distribution fitting. The correlation between q PAH and other physical properties of galaxies, i.e., gas-phase metallicity ( $12+\mathrm{log}({\rm{O}}/{\rm{H}})$ ), stellar mass, and specific star-formation rate (sSFR) are explored. As in previous studies, q PAH values of galaxies with high metallicity are found to be higher than those with low metallicity. The strength of PAH emission is also positively correlated with the stellar mass and negatively correlated with the sSFR. The correlation between q PAH and each parameter still exists even after the other two parameters are fixed. In addition to the PAH strength, the application of metallicity-dependent gas-to-dust mass ratio appears to work well to estimate gas mass that matches the observed relationship between molecular gas and physical parameters. The result obtained will be used to calibrate the observed PAH luminosity-total infrared luminosity relation, based on the variation of MIR-FIR SED, which is used in the estimation of hidden star formation.

Keywords: Polycyclic aromatic hydrocarbons, Galaxy properties, Spectral energy distribution, Infrared galaxies, Galaxy evolution
The Impact of Bayesian Hyperpriors on the Population-level Eccentricity Distribution of Imaged Planets. Orbital eccentricities directly trace the formation mechanisms and dynamical histories of substellar companions. Here, we study the effect of hyperpriors on the population-level eccentricity distributions inferred for the sample of directly imaged substellar companions (brown dwarfs and cold Jupiters) from hierarchical Bayesian modeling (HBM). We find that the choice of hyperprior can have a significant impact on the population-level eccentricity distribution inferred for imaged companions, an effect that becomes more important as the sample size and orbital coverage decrease to values that mirror the existing sample. We reanalyze the current observational sample of imaged giant planets in the 5-100 au range from Bowler et al. and find that the underlying eccentricity distribution implied by the imaged planet sample is broadly consistent with the eccentricity distribution for close-in exoplanets detected using radial velocities. Furthermore, our analysis supports the conclusion from that study that long-period giant planets and brown dwarf eccentricity distributions differ by showing that it is robust to the choice of hyperprior. We release our HBM and forward-modeling code in an open-source Python package, ePop!, and make it freely available to the community.

Keywords: Extrasolar gaseous giant planets
TOI-1136 is a Young, Coplanar, Aligned Planetary System in a Pristine Resonant Chain. Convergent disk migration has long been suspected to be responsible for forming planetary systems with a chain of mean-motion resonances (MMRs). Dynamical evolution over time could disrupt the delicate resonant configuration. We present TOI-1136, a 700 ± 150 Myr old G star hosting at least six transiting planets between ~2 and 5 R ⊕. The orbital period ratios deviate from exact commensurability by only 10-4, smaller than the ~10-2 deviations seen in typical Kepler near-resonant systems. A transit-timing analysis measured the masses of the planets (3-8M ⊕) and demonstrated that the planets in TOI-1136 are in true resonances with librating resonant angles. Based on a Rossiter-McLaughlin measurement of planet d, the star's rotation appears to be aligned with the planetary orbital planes. The well-aligned planetary system and the lack of a detected binary companion together suggest that TOI-1136's resonant chain formed in an isolated, quiescent disk with no stellar flyby, disk warp, or significant axial asymmetry. With period ratios near 3:2, 2:1, 3:2, 7:5, and 3:2, TOI-1136 is the first known resonant chain involving a second-order MMR (7:5) between two first-order MMRs. The formation of the delicate 7:5 resonance places strong constraints on the system's migration history. Short-scale (starting from ~0.1 au) Type-I migration with an inner disk edge is most consistent with the formation of TOI-1136. A low disk surface density (Σ1 au ≲ 103g cm-2; lower than the minimum-mass solar nebula) and the resultant slower migration rate likely facilitated the formation of the 7:5 second-order MMR.

Keywords: Exoplanet dynamics, Exoplanet evolution, Exoplanet migration, Exoplanet formation
A Catalog of Habitable Zone Exoplanets. The search for habitable planets has revealed many planets that can vary greatly from an Earth analog environment. These include highly eccentric orbits, giant planets, different bulk densities, relatively active stars, and evolved stars. This work catalogs all planets found to reside in the habitable zone (HZ) and provides HZ boundaries, orbit characterization, and the potential for spectroscopic follow-up observations. Demographics of the HZ planets are compared with a full catalog of exoplanets. Extreme planets within the HZ are highlighted, and how their unique properties may affect their potential habitability is discussed. Kepler-296 f is the most eccentric ≤2 R ⊕ planet that spends 100% of its orbit in the HZ. HD 106270 b and HD 38529 c are the most massive planets (≤13 M J) that orbit within the HZ, and are ideal targets for determining the properties of potential hosts of HZ exomoons. These planets, along with the others highlighted, will serve as special edge cases to the Earth-based scenario, and observations of these targets will help test the resilience of habitability outside the standard model. The most promising observational HZ target that is known to transit is GJ 414 A b. Of the transiting, ≤2 R ⊕ HZ planets, LHS 1140 b, TRAPPIST-1 d, and K2-3 d are the most favorable. Of the nontransiting HZ planets, HD 102365 b and 55 Cnc f are the most promising, and the best nontransiting candidates that have ≤2 R ⊕ are GJ 667 C c, Wolf 1061 c, Ross 508 b, Teegarden's Star b, and Proxima Cen b.

Keywords: Observational astronomy, Exoplanet catalogs, Transits, Exoplanets, Exoplanet astronomy, Astrobiology, Planet hosting stars, Radial velocity, Habitable zone, Habitable planets
Automatic Classification of Galaxy Morphology: A Rotationally-invariant Supervised Machine-learning Method Based on the Unsupervised Machine-learning Data Set. Classification of galaxy morphology is a challenging but meaningful task for the enormous amount of data produced by the next-generation telescope. By introducing the adaptive polar-coordinate transformation, we develop a rotationally-invariant supervised machine-learning (SML) method that ensures consistent classifications when rotating galaxy images, which is always required to be satisfied physically, but difficult to achieve algorithmically. The adaptive polar-coordinate transformation, compared with the conventional method of data augmentation by including additional rotated images in the training set, is proved to be an effective and efficient method in improving the robustness of the SML methods. In the previous work, we generated a catalog of galaxies with well-classified morphologies via our developed unsupervised machine-learning (UML) method. By using this UML data set as the training set, we apply the new method to classify galaxies into five categories (unclassifiable, irregulars, late-type disks, early-type disks, and spheroids). In general, the result of our morphological classifications following the sequence from irregulars to spheroids agrees well with the expected trends of other galaxy properties, including Sérsic indices, effective radii, nonparametric statistics, and colors. Thus, we demonstrate that the rotationally-invariant SML method, together with the previously developed UML method, completes the entire task of automatic classification of galaxy morphology.

Keywords: Astrostatistics techniques, Galaxy structure, Astronomy data analysis