Sazuna/UAT_keywords huggingface dataset:
Validation of a Third Earth-sized Planet in the TOI-2267 Binary System. We report the validation of a third terrestrial exoplanet in the nearby (22 pc) TOI-2267 system. TOI-2267 is a binary system with stellar components TOI-2267A (M5, 3030 K) and TOI-2267B (M6, 2930 K), with an on-sky separation of 0 .″ 384 (8 au projected separation). TOI-2267 hosts two Earth-sized planets (TOI-2267 b, 1.00 ± 0.11R⊕, and TOI-2267 c, 1.14 ± 0.13R⊕, if orbiting the primary star; or 1.22 ± 0.29R⊕and 1.36 ± 0.33R⊕, respectively, if orbiting the secondary star) with orbital periods of 2.3 and 3.5 days. This system also contains a third Earth-sized planet candidate with an orbital period of 2.0 days that was previously identified as a likely planet with a low false-positive probability, but could not be firmly validated due to the lack of independent observations beyond TESS data. We combine two new transit observations from the 5.1 m Hale Telescope at Palomar Observatory with archival TESS data and high-resolution imaging to statistically validate the planetary nature of TOI-2267 d (0.98 ± 0.09R⊕ if orbiting the primary star, or 1.77 ± 0.43R⊕ if orbiting the secondary star) using the updated TRICERATOPS+ pipeline. We attempt to determine the host star for TOI-2267 d using a transit shape stellar density analysis, but are unable to conclusively assign a host. Our validation of TOI-2267 d suggests that TOI-2267 either is the first known double-transiting M-dwarf binary system or hosts three planets in an extremely compact orbital configuration.

Keywords: Extrasolar rocky planets, M dwarf stars, Binary stars
Condensation Clouds in Substellar Atmospheres with Virga. Here we present an open-source cloud model for substellar atmospheres, called Virga. The Virga-v0 series has already been widely adopted in the literature. It is written in Python and has heritage from the A. S. Ackerman &amp; M. S. Marley model (often referred to as eddysed), used to study clouds on both exoplanets and brown dwarfs. In the development of the official Virga-v1 we have retained all the original functionality of eddysed and updated/expanded several components, including the back-end optical constant data, calculations of the Mie properties, available condensate species, saturation vapor pressure curves, and formalism for fall speed calculations. Here we benchmark Virga by reproducing key results in the literature, including the SiO2 cloud detection in WASP-17 b and the brown dwarf Sonora Diamondback model series. Development of Virga is ongoing, with future versions already planned and ready for release. We encourage community feedback and collaborations within the GitHub code repository.

Keywords: Atmospheric clouds, Brown dwarfs, Exoplanet atmospheres
From Earths to Super-Earths: Five New Small Planets Transiting M Dwarf Stars. Earth-sized planets transiting M dwarf stars present one of the best opportunities with current facilities for studying the atmospheric and bulk compositions of terrestrial worlds. Here, we statistically validate five new transiting Earth and super-Earth sized planets orbiting M dwarf stars using a combination of light curves from the Transiting Exoplanet Survey Satellite, multicolor observations from Palomar and Las Cumbres Observatory, high-resolution imaging, and stellar spectroscopy. The sample includes TOI-5716 b, an Earth-sized planet (Rp = 0.96 ± 0.05 R⊕) with a 6.766 day orbit around a metal-poor thin-disk star ([Fe/H] = −0.54 ± 0.10); TOI-5728 b, a super-Earth (Rp = 1.31 ± 0.05 R⊕) on an 11.497 day orbit; and TOI-5736 b, a larger planet (Rp = 1.56 ± 0.07 R⊕) with an ultrashort period of just 0.649 days. We also statistically validate a multiplanet system, TOI-5489, hosting two similarly sized super-Earths: TOI-5489 b (Rp = 1.40 ± 0.05 R⊕) and TOI-5489 c (Rp = 1.28 ± 0.07 R⊕) with orbital periods of 3.152 and 4.921 days, respectively. Due to their longer orbital periods, TOI-5716 b and TOI-5728 b both have equilibrium temperatures ≤ 400 K, making them useful test cases for studies of atmospheric mass loss. If TOI-5728 b is confirmed to have an Earth-like bulk composition, it would join the very small sample of rocky planets orbiting mid-to-late M dwarfs that lie below the cosmic shoreline and therefore may have retained high mean molecular weight atmospheres.

Keywords: Extrasolar rocky planets, Transits, Infrared photometry
Synthesis Imaging with a Lunar Orbit Array. I. Global Sky Map and Its Systematics. Ground-based radio astronomical observation at frequencies below 30 MHz is hampered by the Ionosphere and radio frequency interference. The Discovering Sky at the Longest wavelength mission, also known as the Hongmeng mission, employs a linear array of satellites on a circular orbit around the Moon to make interferometric observations in this band. Though vastly different from the usual ground-based arrays, the interferometric visibility data collected by such an array are linearly related to the sky map, and the reconstruction is, in principle, an inversion problem of linear mapping. In this paper, we investigate a number of issues in the algorithm of global map reconstruction, focusing on the impact of subpixel noise induced by the finite pixelization of the sky and errors due to regularization. We find that in the reconstruction process, if one builds up the beam matrix, which relates the sky pixels to the visibilities, by naively evaluating its elements at each of the pixel centers, then the subpixel noise can give rise to a significant aliasing effect. However, this effect can be effectively mitigated by a simple pixel-averaging method. Based on the evaluation of the image quality using the correlation coefficient between the input and reconstructed map, and the signal-to-noise ratio, we discuss the selection strategy of the regularization parameter, and show that the sky can be well reconstructed with a reasonable choice of the regularization parameter.

Keywords: Aperture synthesis, Galactic radio sources, Interstellar absorption, Radio interferometry, Radio astronomy
Characterization of an Optical Transfer Function─based Phasing Technique for India's Large Segmented Mirror Telescope. The upcoming 10 m class large Indian telescope is proposed to be built using segmented mirror technology. To achieve diffraction-limited image quality with a segmented mirror telescope, it is important to phase mirror segments with very high precision. We have explored an optical transfer function (OTF)─based technique for segment phasing. The major advantage of this approach is that it enables highly accurate phase measurements over a large capture range without requiring dedicated complex optics or mechanisms. Through extensive simulations and laboratory experiments, we have tested the feasibility of using this technique for the proposed large telescope. From extensive simulations, we found that by using optical filters of different bandwidths, the modulation transfer function allows a measurement of piston errors as large as 50─100 μm and can reduce this down to 25─30 nm. Another advantage of using the OTF is that it inherently allows simultaneous measurement of phase errors in a large number of mirror segments without the use of any specialized optical elements. In this paper we present our results from simulations and laboratory experiments in relation to the proposed 10 m class segmented mirror telescope.

Keywords: Optical telescopes, Astronomical optics, Astronomical instrumentation
WIYN Open Cluster Study. XCVII. An Extended Radial-velocity Survey and Spectroscopic Binary Orbits in the Open Cluster NGC 188. We present 35 new spectroscopic-binary orbits from our extended radial-velocity (RV) survey of the old (6.4 ± 0.2 Gyr) open cluster NGC 188. Using data from the WIYN Open Cluster Study (WOCS) and APOGEE-2, this work nearly doubles the temporal baseline of the previous RV study of NGC 188. We obtain orbital solutions within a stellar sample that spans a magnitude range of 10.8 ≤ G ≤ 16.5 (0.9─1.2 M⊙). With revised membership determinations using Gaia DR3 proper motions and parallaxes, we reassess the cluster binary frequency and period-eccentricity distribution. The incompleteness-corrected binary frequency is 33.1% ± 3.8% for periods less than 104 days, and the tidal-circularization period is  14.4−0.11+0.14  days. We find evidence that giants are deficient in short-period orbits and suggest that the missing giants may have undergone mass transfer and in part formed the population of blue straggler stars (BSSs) and blue lurkers. Among the binaries of note, we highlight WOCS 3953 as a blue lurker candidate, WOCS 5020 and WOCS 4945 as very long-period eccentric BSSs, and WOCS 4230 as a BSS with a very close WD companion.

Keywords: Binary stars, Radial velocity, Spectroscopic binary stars, Open star clusters, Roche lobe overflow, Blue straggler stars, Orbit determination
Metrics for Optimizing Searches for Orbital Precession and Tidal Decay via Transit Timing and Occultation Timing. Short-period exoplanets may exhibit orbital precession driven by several different processes, including tidal interactions with their host stars and secular interactions with additional planets. This motion manifests as periodic shifts in the timing between transits, which may be detectable via high-precision and long-baseline transit- and occultation-timing measurements. Detecting precession and attributing it to a particular process may constrain the tidal responses of planets and point to the presence of otherwise undetected perturbers. However, over relatively short timescales, orbital decay driven by the same tidal interactions can induce transit-timing signals similar to the precession signal, and distinguishing between the two processes requires robust assessment of the model statistics. In this context, occultation observations can help distinguish the two signals, but determining the precision and scheduling of observations sufficient to meaningfully contribute can be complicated. In this study, we expand on earlier work focused on searches for tidal decay to map out simple metrics that facilitate detection of precession and how to distinguish it from tidal decay. We discuss properties for a short-period exoplanet system that can maximize the likelihood for detecting such signals and prospects for contributions from citizen-science observations.

Keywords: Exoplanet dynamics, Star-planet interactions, Timing variation methods, Transit timing variation method
Discovery of a Double-core Dwarf Galaxy in a Major Wet Merger: MCG+08-16-005. I present the discovery of a dwarf galaxy with double cores, MCG+08-16-005, observed by an Integral Field Unit. Based on photometric and spatially resolved spectroscopic analyses, the galaxy is suggested as an ongoing dwarf-dwarf merger. MCG+08-16-005 is a galaxy pair embedded in a large-scale filament, located at a distance of 31.2 Mpc, with Mr = − 17.39 mag, g − r = 0.37 mag, and a stellar mass of 8.3 × 108 M⊙. The double cores are clearly shown in grz-band images, with a projected separation of about 6″ (902 pc). The cores exhibit blue colors, while the outer regions appear red, consistent with the colors of dwarf elliptical galaxies found in the Virgo cluster. The estimated mass ratio of the expected progenitors is about 1.75, suggesting that this is a major dwarf-dwarf merger. Spatially resolved spectroscopy reveals rotational motions in both the stellar and gaseous components. The star-formation rates of the cores are 0.046 and 0.029 M⊙ yr−1, indicating that the galaxy is undergoing a gas-rich wet merger. The gas-phase abundances in the cores are characterized by lower O/H and higher N/O ratios compared to the surrounding regions, suggesting that pristine gas is processed during the merger. The cores are expected to be merged in about 81 Myr. Through this wet major dwarf-dwarf merger, MCG+08-16-005 exhibits properties consistent with those of a quiescent blue compact dwarf galaxy in terms of HI content and star-formation activity. MCG+08-16-005 is likely in a transitional phase in its internal kinematics, between Sm and dE galaxies.

Keywords: Blue compact dwarf galaxies, Galaxy chemical evolution, Stellar kinematics, Star formation, Galaxy evolution, Galaxy mergers
JWST TRAPPIST-1 e/b Program: Motivation and First Observations. One of the forefront goals in the field of exoplanets is the detection of an atmosphere on a temperate terrestrial exoplanet, and among the best suited systems to do so is TRAPPIST-1. However, JWST transit observations of the TRAPPIST-1 planets show significant contamination from stellar surface features that we are unable to confidently model. Here, we present the motivation and first observations of our JWST multicycle program of TRAPPIST-1 e, which utilize close transits of the airless TRAPPIST-1 b to model-independently correct for stellar contamination, with the goal of determining whether TRAPPIST-1 e has an Earth-like mean molecular weight atmosphere containing CO2. We present our simulations, which show that with 15 close transit observations, we will be able to detect this atmosphere on TRAPPIST-1 e at  ∆lnZ=5  or greater confidence assuming we are able to correct for stellar contamination using the close transit observations. We also show the first three observations of our program. We find that our ability to correct for stellar contamination can be inhibited when strong stellar flares are present, as flares can break the assumption that the star does not change meaningfully between planetary transits. The cleanest observation demonstrates the removal of stellar contamination contribution through an increased preference for a flat line over the original TRAPPIST-1 e spectrum, but highlights how minor data analysis assumptions can propagate significantly when searching for small atmospheric signals. This is amplified when using the signals from multiple planets, which is important to consider as we continue our atmospheric search.

Keywords: Exoplanet astronomy, Exoplanets, Exoplanet atmospheres, Extrasolar rocky planets
ELFO: A Python Package for Emission Line Fitting Optimization in Integral Field Spectroscopy Data. Integral field spectroscopy (IFS) provides spatially resolved spectra, enabling detailed studies that address the physical and kinematic properties of the interstellar medium. A critical step in analyzing IFS data is the decomposition of emission lines, where different velocity components are often modeled with Gaussian profiles. However, conventional fitting methods that treat each spectrum independently often yield spatial discontinuities in the fitting results. Here, we present Emission Line Fitting Optimization (ELFO), a Python package for IFS spectral fitting. ELFO uses the results of neighboring spectra to determine multiple initial guesses and selects the result that exhibits spatial smoothness. We tested ELFO on IFS data of two quasars obtained from the Multi-Unit Spectroscopic Explorer, where it successfully corrected anomalous fits, revealed previously unresolved substructures, and made large-scale kinematic structures more evident. With minor modifications, this method can also be easily adapted to other IFS data and different emission lines.

Keywords: Open source software, Quasars
Background Intensity Estimation for Cassini─ISS Image Using Deep-learning-based Diffusion Model. Accurate background intensity estimation is crucial for precise astrometric measurements in astronomical imaging, particularly in complex scenarios such as those encountered in Cassini Imaging Science Subsystem (ISS) observations of Saturn's ring system. Traditional methods such as polynomial fitting and statistical methods often fail in non-uniform conditions, such as those caused by Saturn's rings or scattered light, due to mismatched assumptions and reliance on prior knowledge. This results in biased estimates and poor generalizability. We propose a deep learning framework based on the Denoising Diffusion Probabilistic Model (DDPM) to address these challenges. By learning noise patterns and iteratively reconstructing backgrounds, DDPM improves background intensity estimation in ring─gap regions of ISS images by up to 62% relative to polynomial fitting. Additionally, when applied to centroiding of unresolved satellites in ring-gap region, DDPM-based background estimation enhances positional precision by about 14% in the line direction and 15% in the sample direction. The framework autonomously captures spatial correlations, requires no manual parameter tuning, and generalizes across diverse backgrounds. These characteristics make it a promising, assumption-light solution for background estimation tasks in astrometry, photometry, and source detection, with potential applications to exoplanet transit imaging, deep-field surveys, and future missions.

Keywords: Computational astronomy, Neural networks, Astrometry, Astronomical methods, Astronomy image processing
A Search for Late-type Brown Dwarfs in the Euclid Quick Data Release 1. We present the identification and characterization of 15 mid-to-late T dwarf candidates in the Euclid Quick Release 1 (Q1) data set, based on a combined photometric and spectroscopic analysis. Candidates were initially selected via color-based cuts in the Euclid YE − JE and JE − HE color─color space, targeting the region occupied by ultracool dwarfs (UCDs) in synthetic photometry from the A. Sanghi et al. sample. From an initial pool of 38,845 sources, we extracted low-resolution near-infrared spectra from the Euclid Near-Infrared Spectrometer and Photometer instrument and applied a two-stage validation procedure that included spectral template fitting followed by visual inspection. Eight of the 15 validated candidates are newly identified objects with no prior literature association. We examined their morphological and photometric properties, and compared them with established spectral standards. Photometric distances were derived using band-averaged distance modulus estimates. We discuss the limitations and promise of the Euclid survey for UCD studies, and demonstrate the potential for discovering substellar populations beyond the reach of current wide-field surveys.

Keywords: Near infrared astronomy, Broad band photometry, Brown dwarfs, T dwarfs
Orbits of Twelve Multiple Stars. Inner and outer orbits in 12 hierarchical stellar systems are determined using high-resolution speckle imaging, radial velocities, or both. Masses and fluxes of the components are estimated. The Hipparcos numbers of the main stars are 7111, 12912, 17895, 20375, 42424, 68717, 77439, 79076, 90253, 97922, and 102855; the faint triple WDS J10367+1522 has no Hipparcos number. Four systems are quadruples of the 3 + 1 hierarchy; the rest are triple. Two triples with low-mass M-type components are approximately planar, with moderately eccentric orbits and near-unit mass ratios. The shortest inner period of 0.27 day is found in the newly identified contact eclipsing pair belonging to the misaligned quadruple HIP 97922. The compact system HIP 102855 (periods 15.4 and 129 days) identified by Gaia is confirmed here and has an additional companion at 6″. This work contributes new data for the study of diverse architectures of stellar hierarchies in the field.

Keywords: Spectroscopic binary stars, Multiple stars, Binary stars, Visual binary stars
Modeling the Impact of Unresolved Stellar Companions on Detection Sensitivity in Kepler's Small-planet Occurrence Rates. Unresolved stellar companions can cause both underestimations in the radii of transiting planets and overestimations of their detectability, affecting our ability to reliably measure planet occurrence rates. To quantify the latter, we identified a control sample of 198 Kepler stars with sensitivity to Earth-like planets if they were single stars, and imaged them with adaptive optics. In 20% of systems, we detected stellar companions that were close enough to go unresolved in Kepler observations. We calculated the distribution of planet radius correction factors needed to adjust for these observed companions, along with simulations of undetected companions to which our observations were not sensitive. We then used these correction factors to optimize an occurrence rate model for small, close-in planets while correcting Kepler's detection efficiency for the presence of unresolved companions, and quantified how this correction affects occurrence estimates. Median occurrence rates for small planets between 2 and 100 days increased by an average factor of 1.08─1.19 (depending on statistical treatments), with the largest differences found for smaller planets at larger orbital periods. We found that the frequency of Earth-sized planets in the habitable zone (η⊕) increased by a factor of  1.18−0.66+0.43 ─ 1.46−0.83+0.53  when accounting for the effect of unresolved companions on Kepler's detection sensitivity.

Keywords: Multiple stars, Habitable zone, Exoplanets
A Deep Learning─Based Approach for Dielectric Permittivity Inversion of RIMFAX Ground-penetrating Radar Data. The dielectric permittivity is a crucial parameter in planetary ground-penetrating radar (GPR) missions, such as the RIMFAX radar onboard the Mars 2020 Perseverance rover. It characterizes subsurface materials and enables depth interpretation of radargrams. In this study, we develop a deep learning─based approach for inverting dielectric permittivity from Radar Imager for Mars' Subsurface Experiment (RIMFAX) GPR data. The architecture integrates a convolutional neural network, Bi-LSTM, and a self-attention mechanism, providing a principled framework for leveraging the sequential nature of GPR echoes, capturing long-range subsurface dependencies, and enhancing both the robustness and accuracy of inversions. The input is 1D processed GPR data, and the output is the corresponding 1D dielectric permittivity profile. By combining multiple 1D dielectric permittivity profiles, complex 2D profiles can be constructed. A large volume of synthetic data is used to train the model, allowing it to directly capture the intrinsic relationship between GPR data and dielectric permittivity. The approach is validated on the test set and then applied to the RIMFAX GPR data acquired by the Perseverance rover on Sols 389 and 770. The prediction results effectively reveal key characteristics of the subsurface sedimentary structure, including the number of layers, thicknesses, and the geometry of their contacts. It is broadly consistent with findings reported in prior research, demonstrating the great potential and promising applicability of the approach for dielectric permittivity inversion. However, in such complex planetary radar data, the true dielectric permittivity remains uncertain, and caution is therefore required when using permittivity estimates to infer subsurface structure.

Keywords: Deep space probes, Mars, Radar observations