Sazuna/UAT_keywords huggingface dataset:
A Unified Treatment of Kepler Occurrence to Trace Planet Evolution. I. Methodology. We present Kepler exoplanet occurrence rates for planets between 0.5 and 16 R ⊕ and between 1 and 400 days. To measure occurrence, we use a nonparametric method via a kernel density estimator and use bootstrap random sampling for uncertainty estimation. We use a full characterization of completeness and reliability measurements from the Kepler Data Release 25 catalog, including detection efficiency, vetting completeness, astrophysical reliability, and false alarm reliability. We also include more accurate and homogeneous stellar radii from Gaia Data Release 2. In order to see the impact of these final Kepler properties, we revisit benchmark exoplanet occurrence rate measurements from the literature. We compare our measurements with previous studies to both validate our method and observe the dependence of these benchmarks on updated stellar and planet properties. For FGK stars, between 0.5 and 16 R ⊕ and between 1 and 400 days, we find an occurrence of 1.52 ± 0.08 planets per star. We investigate the dependence of occurrence as a function of radius, orbital period, and stellar type and compare with previous studies with excellent agreement. We measure the minimum of the radius valley to be ${1.78}_{-0.16}^{+0.14}$ R ⊕ for FGK stars and find it to move to smaller radii for cooler stars. We also present new measurements of the slope of the occurrence cliff at 3-4 R ⊕, and find that the cliff becomes less steep at long orbital period. Our methodology will enable us to constrain theoretical models of planet formation and evolution in the future.

Keywords: Exoplanets, Exoplanet astronomy, Exoplanet evolution, Transit photometry, Exoplanet formation
Refining the Stellar Parameters of τ Ceti: a Pole-on Solar Analog. To accurately characterize the planets a star may be hosting, stellar parameters must first be well determined. τ Ceti is a nearby solar analog and often a target for exoplanet searches. Uncertainties in the observed rotational velocities have made constraining τ Ceti's inclination difficult. For planet candidates from radial velocity (RV) observations, this leads to substantial uncertainties in the planetary masses, as only the minimum mass ( $m\sin i$ ) can be constrained with RV. In this paper, we used new long-baseline optical interferometric data from the CHARA Array with the MIRC-X beam combiner and extreme precision spectroscopic data from the Lowell Discovery Telescope with EXPRES to improve constraints on the stellar parameters of τ Ceti. Additional archival data were obtained from a Tennessee State University Automatic Photometric Telescope and the Mount Wilson Observatory HK project. These new and archival data sets led to improved stellar parameter determinations, including a limb-darkened angular diameter of 2.019 ± 0.012 mas and rotation period of 46 ± 4 days. By combining parameters from our data sets, we obtained an estimate for the stellar inclination of 7° ± 7°. This nearly pole-on orientation has implications for the previously reported exoplanets. An analysis of the system dynamics suggests that the planetary architecture described by Feng et al. may not retain long-term stability for low orbital inclinations. Additionally, the inclination of τ Ceti reveals a misalignment between the inclinations of the stellar rotation axis and the previously measured debris disk rotation axis (i disk = 35° ± 10°).

Keywords: Solar analogs, Stellar properties, G dwarf stars, Long baseline interferometry, Spectroscopy
Morphological-based Analyses for Parameterizing Symmetry in Radio Galaxies. The morphology of radio galaxies can provide significant clues to describe the formation and evolution of galaxies in the Universe. Here, we aim to extract the morphological parameters of radio galaxies and define symmetry criteria as some of the essential factors of their shape explanations. We employed 67 radio galaxies, which include Fanaroff-Riley type 1 and type 2 galaxies, and their radio images from the FIRST and LoTSS surveys. We developed an automatic segmentation process to extract morphological properties such as the size of objects, eccentricity, and orientation of segmented regions from data sets. Using a maximum likelihood estimator, we show that the distributions of sizes follow a power-law function with exponents of -0.39 ± 0.06 and -0.55 ± 0.05 for the FIRST and LoTSS data, respectively. We found that type 2 radio galaxies have slightly lower eccentricities than type 1. We studied the relationships between size, eccentricity, and redshift in scatter plots. The size of galaxies (kpc2) demonstrates gently growing trends with increasing eccentricity in their scatter plots. We discussed the possible effect of the redshifts of the galaxies on this result. Depending on the number of segmented regions, we defined symmetry criteria based on proximity to the center of a galaxy in the optical band, eccentricity, orientation, and the quarter (q) of appearance in the image. We found that the mean symmetry obtained for two segmented regions that mainly emerged in two quarters via the condition of $| {q}^{{\prime} }-q^{\prime\prime} | =2$ has a higher value than those obtained for other cases.

Keywords: Radio galaxies, Astronomy data analysis, Catalogs
An Optical Distortion Solution for the Keck I OSIRIS Imager. The astrometric precision and accuracy of an imaging camera is often limited by geometric optical distortions. These must be calibrated and removed to measure precise proper motions, orbits, and gravitationally lensed positions of interesting astronomical objects. Here, we derive a distortion solution for the OSIRIS Imager fed by the Keck I adaptive optics system at the W. M. Keck Observatory. The distortion solution was derived from images of the dense globular clusters M15 and M92 taken with OSIRIS in 2020 and 2021. The set of 403 starlists, each containing ~1000 stars, were compared to reference Hubble catalogs to measure the distortion-induced positional differences. OSIRIS was opened and optically realigned in 2020 November and the distortion solutions before and after the opening show slight differences at the ~20 mas level. We find that the OSIRIS distortion closely matches the designed optical model: large, reaching 20 pixels at the corners, but mostly low order, with the majority of the distortion in the 2nd-order mode. After applying the new distortion correction, we find a median residual of [x, y] = [0.052, 0.056] pixels ([0.51, 0.56] mas) for the 2020 solution, and [x, y] = [0.081, 0.071] pixels ([0.80, 0.71] mas) for the 2021 solution. Comparison between NIRC2 images and OSIRIS images of the Galactic center show that the mean astrometric difference between the two instruments reduces from 10.7 standard deviations to 1.7 standard deviations when the OSIRIS distortion solution is applied. The distortion model is included in the Keck AO Imaging data-reduction pipeline and is available for use on OSIRIS data.

Keywords: Optical position, Astronomical instrumentation, Optical aberration
SPar: Estimating Stellar Parameters from Multiband Photometries with Empirical Stellar Libraries. Modern large-scale photometric surveys have provided us with multiband photometries of billions of stars. Determining the stellar atmospheric parameters, such as the effective temperature (T eff) and metallicities ([Fe/H]), absolute magnitudes (M  G ), distances (d), and reddening values (E(G BP - G RP)) is fundamental to study the stellar populations, structure, kinematics, and chemistry of the Galaxy. This work constructed an empirical stellar library that maps the stellar parameters to multiband photometries from a data set with Gaia parallaxes, LAMOST atmospheric parameters, and optical to near-infrared photometry from several photometric surveys. Based on the stellar library, we developed a new algorithm, SPar (Stellar Parameters from multiband photometry), which fits the multiband stellar photometries to derive the stellar parameters (T eff, [Fe/H], M  G , d, and E(G BP - G RP)) of the individual stars. The algorithm is applied to the multiband photometric measurements of a sample of stars selected from the SMSS survey, which have stellar parameters derived from the spectroscopic surveys. The stellar parameters derived from multiband photometries by our algorithm are in good agreement with those from the spectroscopic surveys. The typical differences between our results and the literature values are 170 K for T eff, 0.23 dex for [Fe/H], 0.13 mag for M  G , and 0.05 mag for E(G BP - G RP). The algorithm proved to be robust and effective and will be applied to the data of future large-scale photometric surveys such as the Mephisto and CSST surveys.

Keywords: Low mass stars, Interstellar dust extinction
The Dependence of Iron-rich Metal-poor Star Occurrence on Galactic Environment Supports an Origin in Thermonuclear Supernova Nucleosynthesis. It has been suggested that a class of chemically peculiar metal-poor stars called iron-rich metal-poor (IRMP) stars formed from molecular cores with metal contents dominated by thermonuclear supernova nucleosynthesis. If this interpretation is accurate, then IRMP stars should be more common in environments where thermonuclear supernovae were important contributors to chemical evolution. Conversely, IRMP stars should be less common in environments where thermonuclear supernovae were not important contributors to chemical evolution. At constant [Fe/H] ≲ -1, the Milky Way's satellite classical dwarf spheroidal (dSph) galaxies and the Magellanic Clouds have lower [α/Fe] than the Milky Way field and globular cluster populations. This difference is thought to demonstrate the importance of thermonuclear supernova nucleosynthesis for the chemical evolution of the Milky Way's satellite classical dSph galaxies and the Magellanic Clouds. We use data from the Sloan Digital Sky Survey Apache Point Observatory Galactic Evolution Experiment and Gaia to infer the occurrence of IRMP stars in the Milky Way's satellite classical dSph galaxies η dSph and the Magellanic Clouds η Mag, as well as in the Milky Way field η MWF and globular cluster populations η MWGC. In order of decreasing occurrence, we find ${\eta }_{\mathrm{dSph}}={0.07}_{-0.02}^{+0.02}$ , ${\eta }_{\mathrm{Mag}}={0.037}_{-0.006}^{+0.007}$ , ${\eta }_{\mathrm{MWF}}={0.0013}_{-0.0005}^{+0.0006}$ , and a 1σ upper limit η MWGC &lt; 0.00057. These occurrences support the inference that IRMP stars formed in environments dominated by thermonuclear supernova nucleosynthesis and that the time lag between the formation of the first and second stellar generations in globular clusters was longer than the thermonuclear supernova delay time.

Keywords: Globular star clusters, Stellar abundances, Galactic archaeology, Small Magellanic Cloud, Large Magellanic Cloud, Chemical enrichment, Type Ia supernovae, Dwarf spheroidal galaxies, Population II stars, Magellanic Clouds, Chemically peculiar stars, Milky Way Galaxy
Iron-rich Metal-poor Stars and the Astrophysics of Thermonuclear Events Observationally Classified as Type Ia Supernovae. I. Establishing the Connection. The progenitor systems and explosion mechanisms responsible for the thermonuclear events observationally classified as Type Ia supernovae are uncertain and difficult to uniquely constrain using traditional observations of Type Ia supernova host galaxies, progenitors, light curves, and remnants. For the subset of thermonuclear events that are prolific producers of iron, we use published theoretical nucleosynthetic yields to identify a set of elemental abundance ratios infrequently observed in metal-poor stars but shared across a range of progenitor systems and explosion mechanisms: [Na, Mg, Co/Fe] &lt; 0. We label stars with this abundance signature "iron-rich metal-poor," or IRMP stars. We suggest that IRMP stars formed in environments dominated by thermonuclear nucleosynthesis and consequently that their elemental abundances can be used to constrain both the progenitor systems and explosion mechanisms responsible for thermonuclear explosions. We identify three IRMP stars in the literature and homogeneously infer their elemental abundances. We find that the elemental abundances of BD +80 245, HE 0533-5340, and SMSS J034249.53-284216.0 are best explained by the (double) detonations of sub-Chandrasekhar-mass CO white dwarfs. If our interpretation of IRMP stars is accurate, then they should be very rare in globular clusters and more common in the Magellanic Clouds and dwarf spheroidal galaxies than in the Milky Way's halo. We propose that future studies of IRMP stars will quantify the relative occurrences of different thermonuclear event progenitor systems and explosion mechanisms.

Keywords: Globular star clusters, Big Bang nucleosynthesis, Explosive nucleosynthesis, Nucleosynthesis, Population II stars, Stellar abundances, Milky Way stellar halo, Type Ia supernovae, Dwarf spheroidal galaxies, Stellar nucleosynthesis, Magellanic Clouds, Chemically peculiar stars
Bayesian Analysis for Remote Biosignature Identification on exoEarths (BARBIE). I. Using Grid-based Nested Sampling in Coronagraphy Observation Simulations for H<SUB>2</SUB>O. Detecting H2O in exoplanet atmospheres is the first step on the path to determining planet habitability. Coronagraphic design currently limits the observing strategy used to detect H2O, requiring the choice of specific bandpasses to optimize abundance constraints. In order to examine the optimal observing strategy for initial characterization of habitable planets using coronagraph-based direct imaging, we quantify the detectability of H2O as a function of signal-to-noise ratio (S/N) and molecular abundance across 25 bandpasses in the visible wavelength range (0.5-1 μm). We use a preconstructed grid consisting of 1.4 million geometric albedo spectra across a range of abundance and pressure, and interpolate to produce forward models for an efficient nested sampling routine, PSGnest. We first test the detectability of H2O in atmospheres that mimic a modern-Earth twin, and then expand to examine a wider range of H2O abundances; for each abundance value, we constrain the optimal 20% bandpasses based on the effective S/N of the data. We present our findings of H2O detectability as functions of S/N, wavelength, and abundance, and discuss how to use these results for optimizing future coronographic instrument design. We find that there are specific points in wavelength where H2O can be detected down to 0.74 μm with moderate-S/N data for abundances at the upper end of Earth's presumed historical values, while at 0.9 μm, detectability is possible with low-S/N data at modern Earth abundances of H2O.

Keywords: Exoplanet atmospheres, Exoplanets
Orbital Alignment of the Eccentric Warm Jupiter TOI-677 b. Warm Jupiters lay out an excellent laboratory for testing models of planet formation and migration. Their separation from the host star makes tidal reprocessing of their orbits ineffective, which preserves the orbital architectures that result from the planet-forming process. Among the measurable properties, the orbital inclination with respect to the stellar rotational axis, stands out as a crucial diagnostic for understanding the migration mechanisms behind the origin of close-in planets. Observational limitations have made the procurement of spin-orbit measurements heavily biased toward hot Jupiter systems. In recent years, however, high-precision spectroscopy has begun to provide obliquity measurements for planets well into the warm Jupiter regime. In this study, we present Rossiter-McLaughlin (RM) measurements of the projected obliquity angle for the warm Jupiter TOI-677 b using ESPRESSO at the VLT. TOI-677 b exhibits an extreme degree of alignment (λ = 0.3 ± 1.3 deg), which is particularly puzzling given its significant eccentricity (e ≈ 0.45). TOI-677 b thus joins a growing class of close-in giants that exhibit large eccentricities and low spin-orbit angles, which is a configuration not predicted by existing models. We also present the detection of a candidate outer brown dwarf companion on an eccentric, wide orbit (e ≈ 0.4 and P ≈ 13 yr). Using simple estimates, we show that this companion is unlikely to be the cause of the unusual orbit of TOI-677 b. Therefore, it is essential that future efforts prioritize the acquisition of RM measurements for warm Jupiters.

Keywords: Exoplanet dynamics, Exoplanet migration, Transits, Exoplanets, Planetary alignment, Radial velocity
Optical Studies of Seven Bright Southern Cataclysmic Variable Stars. We report spectroscopic observations of seven bright southern cataclysmic variable stars, collected on a single two-week observing run using the 1.9 m Radcliffe telescope at the South African Astronomical Observatory. We used a radial-velocity time series, in some cases in combination with other data, to determine or clarify orbital periods for five of them, namely ATO J061.1478-31.0634, BMAM-V547, MGAB-V202, NSV 4202, and V1147 Cen. For BMAM-V547, we use data from the Transiting Exoplanet Survey Satellite (TESS) to corroborate and sharpen the orbital period; the TESS data also show a photometric period near 3.93 days, likely indicating precession of the accretion disk. Also, we find a periodic modulation in the radial velocities of the SU UMa-type dwarf nova Var Ret2005, but are unable to specify a unique cycle count. Finally, we show a spectrum of ASASSN-V J061528.41-412007.3 that appears typical of a luminous novalike variable.

Keywords: Nova-like variable stars, Cataclysmic variable stars, U Geminorum stars, SU Ursae Majoris stars
Beating Stellar Systematic Error Floors Using Transit-based Densities. It has long been understood that the light curve of a transiting planet constrains the density of its host star. That fact is routinely used to improve measurements of the stellar surface gravity and has been argued to be an independent check on the stellar mass. Here we show how the stellar density can also dramatically improve the precision of the radius and effective temperature of the star. This additional constraint is especially significant when we properly account for the 4.2% radius and 2.0% temperature systematic errors inherited from photometric zero-points, model atmospheres, interferometric calibration, and extinction. In the typical case, we can constrain stellar radii to 3% and temperatures to 1.75% with our evolutionary-model-based technique. In the best real-world cases, we can infer radii to 1.6% and temperatures to 1.1%-well below the systematic measurement floors-which can improve the precision in the planetary parameters by a factor of two. We explain in detail the mechanism that makes it possible and show a demonstration of the technique for a near-ideal system, WASP-4. We also show that both the statistical and systematic uncertainties in the parallax from Gaia DR3 are often a significant component of the uncertainty in L * and must be treated carefully. Taking advantage of our technique requires simultaneous models of the stellar evolution, bolometric flux (e.g., a stellar spectral energy distribution), and the planetary transit, while accounting for the systematic errors in each, as is done in EXOFASTv2.

Keywords: Measurement error model, Stellar evolutionary models, Exoplanet astronomy, Spectral energy distribution, Planet hosting stars, Exoplanet detection methods, Transit photometry
Strong [O III] λ5007 Compact Galaxies Identified from SDSS DR16 and Their Scaling Relations. Green-pea galaxies are a special class of star-forming compact galaxies with strong [O III]λ5007 and considered as analogs of high-redshift Lyα-emitting galaxies and potential sources for cosmic reionization. In this paper, we identify 76 strong [O III]λ5007 compact galaxies at z &lt; 0.35 from DR16 of the Sloan Digital Sky Survey. These galaxies present relatively low stellar mass, high star-formation rate, and low metallicity. Both the star-forming main-sequence (SFMS) relation and mass-metallicity relation (MZR) are investigated and compared with green-pea and blueberry galaxies collected from literature. It is found that our strong [O III] λ5007 compact galaxies share common properties with those compact galaxies with extreme star formation and show distinct scaling relations in respect to those of normal star-forming galaxies at the same redshift. The slope of SFMS is higher, indicates that strong [O III]λ5007 compact galaxies might grow faster in stellar mass. The lower MZR implies that they may be less chemically evolved and hence on the early stage of star formation. A further environmental investigation confirms that they inhabit relatively low-density regions. Future large-scale spectroscopic surveys will provide more details on their physical origin and evolution.

Keywords: Metallicity, Star formation, Emission line galaxies
Lensing in the Blue. II. Estimating the Sensitivity of Stratospheric Balloons to Weak Gravitational Lensing. The Superpressure Balloon-borne Imaging Telescope (SUPERBIT) is a diffraction-limited, wide-field, 0.5 m, near-infrared to near-ultraviolet observatory designed to exploit the stratosphere's space-like conditions. SUPERBIT's 2023 science flight will deliver deep, blue imaging of galaxy clusters for gravitational lensing analysis. In preparation, we have developed a weak-lensing measurement pipeline with modern algorithms for PSF characterization, shape measurement, and shear calibration. We validate our pipeline and forecast SUPERBIT survey properties with simulated galaxy cluster observations in SUPERBIT's near-UV and blue bandpasses. We predict imaging depth, galaxy number (source) density, and redshift distribution for observations in SUPERBIT's three bluest filters; the effect of lensing sample selections is also considered. We find that, in three hours of on-sky integration, SUPERBIT can attain a depth of b = 26 mag and a total source density exceeding 40 galaxies per square arcminute. Even with the application of lensing-analysis catalog selections, we find b-band source densities between 25 and 30 galaxies per square arcminute with a median redshift of z = 1.1. Our analysis confirms SUPERBIT's capability for weak gravitational lensing measurements in the blue.

Keywords: High altitude balloons, Galaxy clusters, Astronomy data analysis, Weak gravitational lensing
Revisiting Orbital Evolution in HAT-P-2 b and Confirmation of HAT-P-2 c. One possible formation mechanism for Hot Jupiters is that high-eccentricity gas giants experience tidal interactions with their host star that cause them to lose orbital energy and migrate inwards. We study these types of tidal interactions in an eccentric Hot Jupiter called HAT-P-2 b, which is a system where a long-period companion has been suggested and hints of orbital evolution were detected. Using 5 additional years of radial velocity (RV) measurements, we further investigate these phenomena. We investigated the long-period companion by jointly fitting RVs and Hipparcos-Gaia astrometry and confirmed this long-period companion, significantly narrowed down the range of possible periods ( ${P}_{2}={8500}_{-1500}^{+2600}$ days), and determined that it must be a substellar object ( ${10.7}_{-2.2}^{+5.2}$ M j). We also developed a modular pipeline to simultaneously model rapid orbital evolution and the long-period companion. We find that the rate and significance of evolution are highly dependent on the long-period companion modeling choices. In some cases the orbital rates of change reached ${de}/{dt}\,=\,{3.28}_{-1.72}^{+1.75}\times {10}^{-3}$ yr-1, d ω/dt = 1.12° ± 0.22° yr-1, which corresponds to a ~321 yr apsidal precession period. In other cases, the data is consistent with de/dt = 7.67 ± 18.6 × 10-4 yr-1, d ω/dt = 0.76° ± 0.24° yr-1. The most rapid changes found are significantly larger than the expected relativistic precession rate and could be caused by transient tidal planet-star interactions. To definitively determine the magnitude and significance of potential orbital evolution in HAT-P-2 b, we recommend further monitoring with RVs and precise transit and eclipse timings.

Keywords: Exoplanets, Hot Jupiters, Radial velocity, Orbital evolution, Astrometry, Star-planet interactions