Sazuna/UAT_keywords huggingface dataset:
Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey. VI. Confirmation of a Long-period Giant Planet Discovered with a Single TESS Transit. We report the discovery and confirmation of TOI-4465 b, a 1.25RJ −0.07RJ+0.08RJ , 5.89MJ ± 0.26MJ giant planet orbiting a G dwarf star at d ≃ 122 pc. The planet was detected as a single-transit event in data from Sector 40 of the Transiting Exoplanet Survey Satellite (TESS) mission. Radial velocity (RV) observations of TOI-4465 showed a planetary signal with an orbital period of ∼102 days and an orbital eccentricity of e = 0.24 ± 0.01. TESS reobserved TOI-4465 in Sector 53 and Sector 80 but did not detect another transit of TOI-4465 b, as the planet was not expected to transit during these observations based on the RV period. A global ground-based photometry campaign was initiated to observe another transit of TOI-4465 b after the RV period determination. The ∼12 hr long transit event was captured from multiple sites around the world and included observations from 24 citizen scientists, confirming the orbital period as ∼102 days. TOI-4465 b is a relatively dense (3.73 ± 0.53 g cm−3), temperate (375─478 K) giant planet. Based on giant planet structure models, TOI-4465 b appears to be enriched in heavy elements at a level consistent with late-stage accretion of icy planetesimals. Additionally, we explore TOI-4465 b's potential for atmospheric characterization and obliquity measurement. Increasing the number of long-period planets by confirming single-transit events is crucial for understanding the frequency and demographics of planet populations in the outer regions of planetary systems.

Keywords: Planetary system formation, Radial velocity, Transit photometry, Exoplanets
Revised Ephemerides of the Martian Satellites, Phobos and Deimos. We report on the new ephemerides (MAR099) for the satellites of Mars derived from a large set of ground-based and spacecraft astrometric measurements. Our integrated orbit fit yielded latest estimates for the Martian tidal parameter τ = k2/Q = 1.816 ± 0.084 × 10‑3 and half the tidal acceleration of Phobos of  s=12ṅ=1.258±0.058×10‑3  deg yr‑2. We used the spacecraft-measured physical libration amplitude of Phobos,  A=1.14±0.03  deg, to fit J2 and C22 and found that the result is consistent with the value derived from its shape and the uniform density assumption. The data show no sensitivity for the physical libration of Deimos. We report on the statistics of the observation residuals, the satellites' orbital elements, and projected uncertainties of the satellites' positions in the next few decades.

Keywords: Atmospheric scintillation, Orbit determination, Natural satellites (Solar system)
A Survey of Model Fits to Brown Dwarf Spectra Through the L–T Sequence. We fit archival near-IR spectra of ∼300 brown dwarfs with atmosphere models from the Sonora and Phoenix groups. Using the parameters of the best-fit models as estimates for the physical properties of the brown dwarfs in our sample, we have performed a survey of how brown dwarf atmospheres evolve with spectral type and temperature. We present the fit results and observed trends. We find that clouds have a more significant impact on near-IR spectra than disequilibrium chemistry, and that silicate clouds influence the near-IR spectrum through the late T types. We note where current atmosphere models are able to replicate the data and where the models and data conflict. We also categorize objects with similar spectral morphologies into families and discuss possible causes for their unique spectral traits. We identify two spectral families with morphologies that are likely indicative of binarity.

Keywords: Brown dwarfs, Infrared spectroscopy, T dwarfs, L dwarfs, Near infrared astronomy
Lens Modeling of STRIDES Strongly Lensed Quasars Using Neural Posterior Estimation. Strongly lensed quasars can be used to constrain cosmological parameters through time-delay cosmography. Models of the lens masses are a necessary component of this analysis. To enable time-delay cosmography from a sample of  O(103)  lenses, which will soon become available from surveys like the Rubin Observatory's Legacy Survey of Space and Time and the Euclid Wide Survey, we require fast and standardizable modeling techniques. To address this need, we apply neural posterior estimation (NPE) for modeling galaxy-scale strongly lensed quasars from the Strong Lensing Insights into the Dark Energy Survey (STRIDES) sample. NPE brings two advantages: speed and the ability to implicitly marginalize over nuisance parameters. We extend this method by employing sequential NPE to increase precision of mass model posteriors. We then fold individual lens models into a hierarchical Bayesian inference to recover the population distribution of lens mass parameters, accounting for out-of-distribution shift. After verifying our method using simulated analogs of the STRIDES lens sample, we apply our method to 14 Hubble Space Telescope single-filter observations. We find the population mean of the power-law elliptical mass distribution slope, γlens, to be  Mγlens=2.13±0.06 . Our result represents the first population-level constraint for these systems. This population-level inference from fully automated modeling is an important stepping stone toward cosmological inference with large samples of strongly lensed quasars.

Keywords: Strong gravitational lensing, Convolutional neural networks
Regression for Astronomical Data with Realistic Distributions, Errors, and Nonlinearity. We have developed a new regression technique, the maximum likelihood (ML)─based method and its variant, the Kolmogorov─Smirnov (KS) test─based method, designed to obtain unbiased regression results from typical astronomical data. A normalizing flow model is employed to automatically estimate the unobservable intrinsic distribution of the independent variable and the unobservable correlation between uncertainty level and intrinsic value of both independent and dependent variables from the observed data points in a variational-inference-based empirical Bayes approach. By incorporating these estimated distributions, our method comprehensively accounts for the uncertainties associated with both independent and dependent variables. Our test on both mock data and real astronomical data from PHANGS-ALMA and PHANGS-JWST demonstrates that, given a sufficiently large sample size (&gt;1000), both the ML-based method and the KS-test-based method significantly outperform the existing widely used methods, particularly in cases of low signal-to-noise ratios. The KS-test-based method exhibits remarkable robustness against deviations from underlying assumptions, complex intrinsic distributions, varying correlations between uncertainty levels and intrinsic values, inaccuracies in uncertainty estimations, outliers, and saturation effects. For sample sizes between 300 and 1000, the ML-based method yields the best performance. In the low-data regime (&lt;300), the ML-based method maintains comparable performance to other state-of-the-art methods. A GPU-compatible Python implementation of our methods, nicknamed "raddest," will be made publicly available upon acceptance of this paper.

Keywords: Astrostatistics techniques, Regression
The Disks In Scorpius─Centaurus Survey (DISCS). I. Four Newly Resolved Debris Disks in Polarized Intensity Light. The presence of infrared excesses around stars directly correlates with spatially resolved imaging detections of circumstellar disks at both millimeter and optical/near-infrared wavelengths. High-contrast imagers have resolved dozens of circumstellar disks with scattered light polarimetric imaging. Many of these detections are members of the Scorpius─Centaurus OB association, demonstrating it to be a rich sample for investigating planetary system architectures and planet─disk interactions. With the goal of expanding the sample of directly imaged debris disks in Scorpius─Centaurus, we conducted the Disks In Scorpius─Centaurus Survey, leveraging knowledge of high-IR excesses and the power of high-contrast polarimetric differential imaging. In combination with the GPIES polarimetric disk survey, we observe seven new Scorpius─Centaurus targets to achieve a 60% complete survey of debris disks with IR excesses exceeding 2.5 × 10−4, resolving four new debris disks. HD 98363, HD 109832, and HD 146181 are resolved for the first time, and HD 112810 is resolved for the first time in polarized intensity. We identify morphological structures that may be indications of planet─disk interactions. We place the systems in the greater context of resolved debris disks, identifying order of magnitude differences in scattered light contrast for a given IR excess, implying gaps in our understanding of the smallest and largest dust grains of a system. We conclude that while thermal emission measurements are correlated with scattered light detection, they poorly predict the magnitude of scattered light brightness. We also establish Scorpius─Centaurus debris disks as critical benchmarks in understanding the properties of disks in the scattering regime.

Keywords: High contrast techniques, Planetary system evolution, OB associations, Polarimetry, Exoplanet systems, Planetary system formation, Direct imaging, Circumstellar disks, Debris disks, Planet formation
A Candidate Giant Planet Companion to the Massive, Young White Dwarf GALEX J071816.4+373139 Informs the Occurrence of Giant Planets Orbiting B Stars. It has been suggested that giant planet occurrence peaks for stars with M* ≈ 3 M⊙ at a value a factor of 4 higher than observed for solar-mass stars. This population of giant planets predicted to frequently orbit main-sequence B stars at a ≈ 10 au is difficult to characterize during the few hundred million years while fusion persists in their host stars. By the time those stars become massive, young white dwarfs, any giant planets present would still be luminous as a consequence of their recent formation. From an initial sample of 2195 Gaia-identified massive, young white dwarfs, we use homogeneous Spitzer Infrared Array Camera (IRAC) photometry to search for evidence of unresolved giant planets. For 30 systems, these IRAC data provide sensitivity to objects with M ≲ 10 MJup, and we identify one candidate with M ≈ 4 MJup orbiting the white dwarf GALEX J071816.4+373139. Correcting for the possibility that some of the white dwarfs in our sample result from mergers, we find a giant planet occurrence  ηGP=0.11‑0.07+0.13  for stars with initial masses M* ≳ 3 M⊙. Our occurrence inference is consistent with both the Doppler-inferred occurrence of giant planets orbiting M* ≈ 2 M⊙ giant stars and the theoretically predicted factor of 4 enhancement in the occurrence of giant planets orbiting M* ≈ 3 M⊙ stars relative to solar-mass stars. Future James Webb Space Telescope NIRCam observations of our sample would provide sensitivity to Saturn-mass planets and thereby a definitive estimate of the occurrence of giant planets orbiting stars with M* ≳ 3 M⊙.

Keywords: Exoplanet detection methods, Exoplanet formation, B stars, Exoplanets
Improving Source Positions in the OCARS Catalog: A First Approach. Optical Characteristics of Astrometric Radio Sources (OCARS) is a compiled catalog of various additional data associated with astrometric radio sources whose coordinates have been determined from very long baseline interferometry observations. It contains source coordinates, object type, redshift, optical, and near-infrared magnitudes. Until now, OCARS source coordinates were simply copied from input catalogs and, as a result, were systematically inhomogeneous. This work is the first attempt to obtain a unified set of radio source coordinates aligned to the International Celestial Reference Frame (ICRF), more especially to the third ICRF release, ICRF3. Comparison of the source coordinates in the old OCARS version as of 2024 December and the new OCARS version as of 2025 March with the ICRF3-SX catalog using the vector spherical harmonics technique showed almost complete elimination of systematic errors in new OCARS positions relative to the ICRF3 frame.

Keywords: Astronomical coordinate systems, Very long baseline interferometry, Astrometry, Radio source catalogs
A Dark, Bare Rock for TOI-1685 b from a JWST NIRSpec G395H Phase Curve. We report JWST NIRSpec/G395H observations of TOI-1685 b, a hot rocky super-Earth orbiting an M2.5V star, during a full orbit. We obtain transmission and emission spectra of the planet and characterize the properties of the phase curve, including its amplitude and offset. The transmission spectrum rules out clear H2-dominated atmospheres, while secondary atmospheres (made of water, methane, sulfur dioxide, or carbon dioxide) cannot be statistically distinguished from a flat line. The emission spectrum is featureless and consistent with a dark surface, ruling out carbon dioxide-, sulfur dioxide-, or methane-dominated atmospheres thicker than 100 mbar. Collecting all evidence, the properties of TOI-1685 b are consistent with a blackbody with no heat redistribution and a low albedo, with a dayside brightness temperature 0.99 ± 0.07 times that of a perfect blackbody in the NIRSpec NRS2 wavelength range (3.823–5.172 μm). Our results add to the growing number of seemingly airless M-star rocky planets, thus constraining the location of the "Cosmic Shoreline." Three independent data reductions have been carried out, all showing a high-amplitude correlated noise component in the white and spectroscopic light curves. The correlated noise properties are different between the NRS1 and NRS2 detectors—importantly, the timescales of the strongest components (4.5 hr and 2.5 hr, respectively)—suggesting the noise is from instrumental rather than astrophysical origins. We encourage the community to look into the systematics of NIRSpec for long time series observations.

Keywords: Extrasolar rocky planets, James Webb Space Telescope, Exoplanets, Exoplanet atmospheres
Detection of H<SUB>2</SUB>O and CO<SUB>2</SUB> in the Atmosphere of the Hot Super-Neptune WASP-166b with JWST. We characterize the atmosphere of the hot super-Neptune WASP-166b (P = 5.44 days, Rp = 6.9 ± 0.3 R⊕, Mp = 32.1 ± 1.6 M⊕, Teq = 1270 ± 30 K) orbiting an F9V star using JWST transmission spectroscopy with NIRISS and NIRSpec (0.85─5.17 μm). With this broad wavelength range, NIRISS provides strong constraints on H2O and clouds (where NIRSpec performs poorly) while NIRSpec captures CO2 and NH3 (where NIRISS performs poorly). Our POSEIDON free chemistry retrievals confirm the detection of H2O (15.2σ significance) and detect CO2 (14.7σ) for the first time. We also find a possible hint of NH3 (2.3σ) and an intermediate pressure cloud deck (2.6σ). Finally, we report inconclusive support for the presence of SO2, CO, and Na, as well as nondetections of CH4, C2H2, HCN, H2S, and K. We verify our results using a TauREx free chemistry retrieval. We also measure with POSEIDON equilibrium chemistry retrievals a superstellar planetary atmospheric metallicity ( log(Z)=1.57−0.18+0.17 ,  Z=37−13+18 ) and planetary C/O ratio ( C/O=0.282−0.053+0.078 ) consistent with the stellar C/O ratio (C/O* = 0.41 ± 0.08). These results are compatible with various planetary formation pathways, especially those that include planetesimal accretion followed by core erosion or photoevaporation. WASP-166b also resides near the edge of the Hot Neptune Desert, a sparse population of intermediate-sized planets at high insolation fluxes; thus, these results and further atmospheric observations of Hot Neptunes will help determine the driving processes in the formation of the Hot Neptune Desert.

Keywords: Exoplanet atmospheric composition , Exoplanets, Hot Neptunes, Transmission spectroscopy, Exoplanet astronomy, James Webb Space Telescope
Stellar Obliquity of the Ultra-short-period Planet System HD 93963. We report an observation of the Rossiter─McLaughlin (RM) effect of the transiting planet HD 93963 Ac, a mini-Neptune planet orbiting a G0-type star with an orbital period of Pc = 3.65 days, accompanied by an inner super-Earth planet with Pb = 1.04 days. We observed a full transit of planet c on 2024 May 3 UT with the Keck/Keck Planet Finder. The observed RM effect has an amplitude of ∼1 m s−1 and implies a sky-projected obliquity of  λ=14−19+17  degrees for HD 93963 Ac. Our dynamical analysis suggests that the two inner planets are likely well aligned with the stellar spin, to within a few degrees, thus allowing both to transit. Along with WASP-47, 55 Cnc, and HD 3167, HD 93963 is the fourth planetary system with an ultrashort-period planet and obliquity measurement(s) of any planet(s) in the system. HD 93963, WASP-47, and 55 Cnc favor largely coplanar orbital architectures, whereas HD 3167 has been reported to have a large mutual inclination (∼100°) between its transiting planets b and c. In this configuration, the probability that both planets transit is low. Moreover, one planet would quickly evolve to be nontransiting due to nodal precession. Future missions such as ESO/PLATO should detect the resulting transit duration variations. We encourage additional obliquity measurements of the HD 3167 system to better constrain its orbital architecture.

Keywords: Exoplanet dynamics, Mini Neptunes, Super Earths, Exoplanets
The NEID Earth Twin Survey. II. Dynamical Masses in Seven High-acceleration Star Systems. We present a set of companion dynamical masses and orbital parameters of seven star systems from the NEID Earth Twin Survey with significant absolute astrometric accelerations between the epochs of Hipparcos and Gaia. These include four binary star systems (HD 68017 AB, 61 Cygni AB, HD 24496 AB, and HD 4614 AB) and three planetary systems (HD 217107, HD 190360, and HD 154345). Our analyses incorporate a long baseline of RVs that includes over 1100 previously unpublished measurements from NEID and MINERVA, extending the overall RV baseline for each system by ≍2.5 yr, as well as relative astrometry for the stellar binary systems where the positions of both stars are well measured. In each case, the combination of astrometry and RVs constrains the three-dimensional acceleration of the host star and enables precise dynamical masses. We publish true masses for three planets whose measurements were previously entangled with their inclinations, four stellar masses with ≲1% relative precision, and improved orbital solutions for all seven systems, including the first for HD 24496 AB. These solutions not only agree with previous estimates, but also improve their fidelity. We also explore each system for evidence of periodic signals in the residuals around our best-fit models, and discuss the potential that the three planetary systems have for being directly imaged. With dynamical mass estimates and reliable orbit ephemerides, these seven star systems represent promising benchmarks for future stellar and planetary characterization efforts, and are amenable for further improvement with the upcoming release of Gaia epoch astrometry.

Keywords: Exoplanet astronomy, Radial velocity, Binary stars, Astrometry
A VLBI Software Correlator for Fast Radio Transients. One major goal in fast radio burst science is to detect fast radio bursts (FRBs) over a wide field of view without sacrificing the angular resolution required to pinpoint them to their host galaxies. Wide-field detection and localization capabilities have already been demonstrated using connected-element interferometry; the CHIME/FRB Outriggers project will push this further using widefield cylindrical telescopes as widefield outriggers for very long baseline interferometry (VLBI). This paper describes an offline VLBI software correlator written in Python for the CHIME/FRB Outriggers project. It includes features well-suited to modern widefield instruments like multibeaming/multiple phase center correlation, pulse gating including coherent dedispersion, and a novel correlation algorithm based on the quadratic estimator formalism. This algorithm mitigates sensitivity loss that arises in instruments where the windowing and channelization is done outside the VLBI correlator at each station, which accounts for a 30% sensitivity drop away from the phase center. Our correlation algorithm recovers this sensitivity on both simulated and real data. As an end-to-end check of our software, we have written a preliminary pipeline for VLBI calibration and single-pulse localization, which we use in Lanman et al. to verify the astrometric accuracy of the CHIME/FRB Outriggers array.

Keywords: Open source software, Very long baseline interferometry, Radio astrometry, Interferometric correlation, Radio transient sources, Radio pulsars
The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. VII. Long-period Variable Stars in the Nearest Starburst Dwarf Galaxy, IC 10. To identify long-period variable (LPV) stars in IC 10—the nearest starburst galaxy of the Local Group—we conducted an optical monitoring survey using the 2.5 m Isaac Newton Telescope with the wide-field camera (WFC) in the i band and V band from 2015 to 2017. We created a photometric catalog for 53,579 stars within the area of CCD4 of WFC (∼0.07 deg2 corresponding to 13.5 kpc2 at the distance of IC 10), of which we classified 536 and 380 stars as LPV candidates, mostly asymptotic giant branch (AGBs) stars and red supergiants, within CCD4 and two half-light radii of IC 10, respectively. By comparing our output catalog to the catalogs from Pan-STARRS, Spitzer Space Telescope, Hubble Space Telescope (HST), and carbon stars from the Canada─France─Hawai'i Telescope survey, we determined the success of our detection method. We recovered ∼73% of Spitzer's sources in our catalog and demonstrated that our survey successfully identified 43% of the variable stars found with Spitzer, and also retrieved 40% of the extremely dusty AGB stars among the Spitzer variables. In addition, we successfully identified ∼70% of HST variables in our catalog. Furthermore, we found all the confirmed LPVs that Gaia DR3 detected in IC 10 among our identified LPVs. This paper is the first in a series on IC 10, presenting the variable star survey methodology and the photometric catalog, available to the public through the Centre de Données Astronomiques de Strasbourg.

Keywords: Local Group, Asymptotic giant branch stars, Stellar populations