Sazuna/UAT_keywords huggingface dataset:
Searching for GEMS: Confirmation of TOI-5573 b, a Cool, Saturn-like Planet Orbiting an M Dwarf. We present the confirmation of TOI-5573 b, a Saturn-sized exoplanet on an 8.79 days orbit around an early M dwarf (3790 K, 0.59 R⊙, 0.61 M⊙, 12.30 Jmag). TOI-5573 b has a mass of  112‑19+18  M⊕(0.35 ± 0.06 MJup) and a radius of 9.75 ± 0.47 R⊕(0.87 ± 0.04 RJup), resulting in a density of  0.66‑0.13+0.16  g cm‑3, akin to that of Saturn. The planet was initially discovered by the Transiting Exoplanet Survey Satellite (TESS) and confirmed using a combination of 11 transits from four TESS Sectors (20, 21, 47, and 74), ground-based photometry from the Red Buttes Observatory, and high-precision radial velocity data from the Habitable-zone Planet Finder and NN-EXPLORE Exoplanet Investigations with Doppler spectrographs, achieving a 5σ precision on the planet's mass. TOI-5573 b is one of the coolest Saturn-like exoplanets discovered around an M-dwarf, with an equilibrium temperature of only 528 ± 10 K, making it a valuable target for atmospheric characterization. Saturn-like exoplanets around M dwarfs likely form through core accretion, with increased disk opacity slowing gas accretion and limiting their mass. The host star's supersolar metallicity supports core accretion, but uncertainties in M-dwarf metallicity estimates complicate definitive conclusions. Compared to other GEMS (Giant Exoplanets around M-dwarf Stars) orbiting metal-rich stars, TOI-5573 b aligns with the observed pattern that giant planets preferentially form around M-dwarfs with supersolar metallicity. Further high-resolution spectroscopic observations are needed to explore the role of stellar metallicity in shaping the formation and properties of giant exoplanets like TOI-5573 b. *Based on observations obtained with the Hobby–Eberly Telescope (HET), which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximillians-Universitaet Muenchen, and Georg-August Universitaet Goettingen. The HET is named in honor of its principal benefactors, William P. Hobby and Robert E. Eberly

Keywords: M dwarf stars, Transits, Exoplanets, Exoplanet systems, Planet hosting stars, Radial velocity, Exoplanet formation
A 70 pc Diameter Nova Superremnant Surrounding the Recurrent Nova RS Ophiuchi. Recurrent novae undergo thermonuclear-powered eruptions separated by less than 100 yr, enabled by subgiant or red giant donors transferring hydrogen-rich matter at very high rates onto their massive white dwarf companions. The most rapidly moving parts of envelopes ejected in successive recurrent nova events are predicted to overtake and collide with the slowest ejecta of the previous eruption, leading to the buildup of vast (∼10–100 pc) superremnants surrounding all recurrent novae, but only three examples are currently known. We report deep narrowband imaging and spectroscopy, which have revealed a ∼70 pc diameter shell surrounding the frequently recurring nova RS Ophiuchi. We estimate the superremnant mass to be ∼20–200 M⊙, expanding at a few tens of km/s, with an age of order 50–100 kyr. Its extremely low surface brightness and large angular size help explain the hitherto surprising absence of nova superremnants. Our results support the prediction that all recurrent novae are surrounded by similar extended structures.

Keywords: Recurrent novae
Interstellar Polarization Survey. V. Galactic Magnetic Field Tomography of the Spiral Arms Using Optical and Near-infrared Starlight Polarization. Interstellar linear polarization occurs when starlight passes through elongated dust grains aligned by interstellar magnetic fields. The observed polarization can come from different dust structures along the line of sight (LOS). By combining polarization measurements with stellar distances, we can study the plane-of-sky Galactic magnetic field (GMF) between the observer and the star and separate the contributions of clouds with different GMF properties. We used optical and near-infrared (NIR) polarization data from three regions in the Galactic plane (∣b∣ &lt; 1° and 19 .° 8 &lt; l &lt; 25 .° 5) to perform a polarization decomposition across the Galactic arms. A comparison between the optical and NIR data showed an optical-to-NIR polarization ratio of two to three along the LOS and a consistent polarization angle across both wavelengths in all studied regions, within the measurement uncertainties. We applied the Bayesian Inference of Starlight Polarization in one dimension and the Gaussian mixture model methods to decompose the polarization in the three regions. The optical and NIR observations complemented each other, consistently identifying nearby (d ≲ 143 pc), intermediate (0.47 kpc &lt; d &lt; 1.2 kpc), and distant (1.5 kpc &lt; d &lt; 2.5 kpc) polarizing clouds, in agreement with previous findings of the Local Bubble wall, the Local Arm, and Sagittarius Arm dust structures. The results from both polarization decomposition methods agree and complement each other. Polarization tomography revealed significant LOS variations in the plane-of-sky magnetic field orientation in two of the three regions. The relative alignment between the magnetic fields traced by starlight polarization and Planck's polarized thermal dust emission at 353 GHz reaffirmed these variations.

Keywords: Milky Way magnetic fields, Galaxy structure, Interstellar magnetic fields, Starlight polarization, Interstellar medium
Five New Sirius-like White Dwarf–Main-sequence Star Systems with MagAO-X. Most known white dwarfs in multiple systems with main-sequence stars have been discovered with M-type companions, because the white dwarf causes detectable UV excess and bluer colors than expected from a single M star. Surveys have shown that the number of white dwarfs in Sirius-like systems within 100 pc of the Sun is lower than expected, suggesting that white dwarfs are being missed in the glare of their main-sequence companions. In this work we have leveraged the angular resolution and high-contrast capabilities, as well as optimization for visible wavelengths, of the extreme adaptive optics (ExAO) instrument MagAO-X to detect new white dwarf companions to AFGK stars. We present the first results of our survey with the ExAO instrument MagAO-X, called The ExAO Pup Search, of 18 targets with seven new candidate companions, five of which are confirmed to be white dwarfs. We discuss the new detections in the context of previous surveys and other detection metric sensitivities and show that we are sensitive to a region not probed by other surveys. Finally we discuss the future of the Pup Search in light of developing technologies.

Keywords: Binary stars, White dwarf stars, Detached binary stars, DA stars, Wide binary stars, Visual binary stars
The CHILES Continuum and Polarization Survey. I. Survey Design and Noise Characterization. We introduce and describe the CHILES Continuum and Polarisation (CHILES Con Pol) Survey, a 1000 hr 1.4 GHz wideband full polarization radio continuum deepfield with the Very Large Array, commensurate with the CHILES H I deepfield. We describe the observational configuration, outline the calibration of the data, and discuss the effect of radio frequency interference on different observing epochs. In addition, we present a novel radio continuum imaging strategy, using well-known baseline subtraction techniques in radio spectral data, and discuss the applications to the removal of artifacts from sources far from the field center. Additionally, we discuss the nature of a low-level image-wide offset, the so-called "negative bowl," and simulate our observations in order that we may both properly understand and correct for this artifact. Using these techniques, we present the first total intensity image of the data which achieves an rms noise of 1.3 μJy beam−1 with a synthesized beam of 4 .″ 5 × 4 .″ 0, the most sensitive L-band image ever taken at this resolution. We then place this image into the broader context of 1.4 GHz radio continuum surveys in the literature, in terms of image sensitivity and fidelity, and μJy level source counts and P(D) analysis.

Keywords: Radio continuum emission, Extragalactic radio sources, Radio interferometry
The CHILES Continuum and Polarization Survey. II. Radio Continuum Source Catalog and Radio Properties. The COSMOS H I Large Extragalactic Survey (CHILES) Continuum and Polarization survey is an ultradeep continuum imaging study of the COSMOS field conducted using the Karl G. Jansky Very Large Array. We obtained 1000 hr of L-band (λ = 20 cm) observations across four spectral windows (SPWs; 1.063–1.831 GHz) in a single pointing and produced a confusion-limited image with an apparent rms noise of 1.67 μJy beam‑1 with a synthesized beam of 5 .″ 5 × 5 .″ 0. This paper reports a 1.4 GHz radio continuum source catalog containing 1678 sources detected above 7σ (flux densities greater than 11.7 μJy), identified using two independent source extraction programs applied to the Stokes I image. Resolved sources dominate at flux density S1.4GHz ≥ 42 μJy. The radio spectral index for each source was derived using a power-law fit across the four SPWs, and we found that a robust spectral index measurement requires a total signal-to-noise ratio of at least 20. Comparisons with previous 1.4 GHz radio continuum surveys show good overall consistency, but evidence for a high degree of catalog incompleteness and the effects of source confusion are evident for some of the earlier studies.

Keywords: Surveys, Extragalactic radio sources, Radio continuum emission
A Panchromatic Characterization of the Evening and Morning Atmosphere of WASP-107 b: Composition and Cloud Variations, and Insight into the Effect of Stellar Contamination. Limb-resolved transmission spectroscopy has the potential to transform our understanding of exoplanetary atmospheres. By separately measuring the transmission spectra of the evening and morning limbs, these atmospheric regions can be individually characterized, shedding light into the global distribution and transport of key atmospheric properties from transit observations alone. In this work, we follow up the recent detection of limb asymmetry on the exoplanet WASP-107 b by reanalyzing literature observations of WASP-107 b using all of James Webb Space Telescope's science instruments (Near Infrared Imager and Slitless Spectrograph (NIRISS), Near-Infrared Camera, Near Infrared Spectrograph (NIRSpec), and Mid-Infrared Instrument) to measure its limb transmission spectra from ∼1 to 12 μm. We confirm the evening–morning temperature difference inferred previously and find that it is qualitatively consistent with predictions from global circulation models. We find evidence for evening–morning variation in SO2 and CO2 abundance, and significant cloud coverage only on WASP-107 b's morning limb. We find that the NIRISS and NIRSpec observations are potentially contaminated by occulted starspots, which we leverage to investigate stellar contamination's impact on limb asymmetry measurements. We find that starspot crossings can significantly bias the inferred evening and morning transmission spectra depending on when they occur during the transit, and develop a simple correction model which successfully brings these instruments' spectra into agreement with the uncontaminated observations.

Keywords: Exoplanet atmospheric composition , Exoplanet atmospheric dynamics, Exoplanet atmospheric variability, Exoplanet atmospheres, Exoplanet atmospheric structure
ELemental Abundances of Planets and Brown Dwarfs Imaged around Stars (ELPIS). II. The Jupiter-like Inhomogeneous Atmosphere of the First Directly Imaged Planetary-mass Companion 2MASS 1207 b. 2MASS 1207 b, the first directly imaged planetary-mass companion, has been instrumental in advancing our understanding of exoplanets and brown dwarfs over the past 20 yr. We have performed extensive atmospheric retrieval analyses of 2MASS 1207 b's JWST/NIRSpec spectrum using petitRADTRANS and a new atmospheric inhomogeneity framework, which characterizes homogeneous atmospheres, patchy clouds, cloud-free hot spots, or the combination of patchy clouds and spots. Among 24 retrieval runs with various assumptions, the most statistically preferred model corresponds to the patchy cloud scheme, with  Teff=1174‑3+4  K,  log(g)=3.62‑0.02+0.03  dex, and  R=1.399‑0.010+0.008  RJup, along with near-solar atmospheric compositions of [M/H] = ‑0.05 ± 0.03 dex and C/O = 0.440 ± 0.012. This model suggests ∼9% of 2MASS 1207 b's atmosphere is covered by thin iron and silicate clouds, producing L-dwarf-like spectra, while the remaining 91% consists of thick iron and silicate clouds, emitting blackbody-like spectra. These thin-cloud patches and thick-cloud regions resemble Jupiter's belts and zones, respectively, and this scenario is consistently supported by other retrieval runs incorporating inhomogeneous atmospheres. We demonstrate that the weak CO absorption of 2MASS 1207 b can be explained by the veiling effects of patchy thick clouds; the absence of 3.3 μm CH4 absorption is attributed to its hot thermal structure, which naturally leads to a CO-dominant, CH4-deficient atmosphere. The retrieved atmospheric models also match the observed variability amplitudes of 2MASS 1207 b. Our analysis reveals that the inferred atmospheric properties show significant scatter in less statistically preferred retrieval runs but converge to consistent values among the preferred ones. This underscores the importance of exploring diverse assumptions in retrievals to avoid biased interpretations of atmospheric properties and formation pathways.

Keywords: Atmospheric composition, Atmospheric clouds, L dwarfs, Exoplanet atmospheres
Updated Mass, Eccentricity, and Tidal Heating Constraints for the Earth-sized Planet LP 791-18 d. LP 791-18 d is a temperate Earth-sized planet (RP = 1.03 R⊕, P = 2.76 days) orbiting a late M dwarf, with an interior super-Earth (LP 791-18 b, RP = 1.2 R⊕, P = 0.95 days) and an exterior sub-Neptune (LP 791-18 c, RP = 2.5 R⊕, P = 4.99 days). Dynamical interactions between LP 791-18 d and c produce transit timing variations (TTVs) that can be used to constrain the planet masses and eccentricities. These interactions can also force a non-zero eccentricity for LP 791-18 d, which raises its internal temperature through tidal heating and could drive volcanic outgassing. We present three new transit observations of LP 791-18 c with Palomar/WIRC, including the most precise TTV measurements (&lt;6 s uncertainty) of this planet to date. We fit these times with a TTV model to obtain updated constraints on the mass, eccentricity, and tidal heat flux of LP 791-18 d. We reduce the mass uncertainty by more than a factor of two (Md = 0.91 ±0.19 M⊕). We perform an updated fit assuming tidally damped free eccentricities and find  ed=0.0011‑0.0008+0.0010  and ec = 0.0001 ± 0.0001, consistent with circular orbits. We find that the observed TTVs are not sensitive to e ≤ ∼0.01. Without a tidally damped eccentricity prior,  ed=0.056‑0.014+0.015 , much higher than the eccentricity predicted by n-body simulations incorporating the effects of dynamical excitation and tidal damping. We predict the timing offset relative to the prediction for a circular orbit of upcoming JWST secondary eclipse observations for LP 791-18 d ( Δt=‑0.2‑2.7+2.0  minutes and  Δt=‑117‑47+41  minutes for the damped and undamped eccentricity cases, respectively), which could tightly constrain the eccentricity and tidal quality factor of this Earth-sized exoplanet.

Keywords: Exoplanet dynamics, Transits, Exoplanet tides, Transit timing variation method, Eccentricity
StarFlow: Leveraging Normalizing Flows for Stellar Age Estimation in SDSS-V DR19. Understanding the ages of stars is crucial for unraveling the formation history and evolution of our Galaxy. Traditional methods for estimating stellar ages from spectroscopic data often struggle with providing appropriate uncertainty estimations and are severely constrained by the parameter space. In this work, we introduce a new approach using normalizing flows—a type of deep generative model—to estimate stellar ages for evolved stars with improved accuracy and robust uncertainty characterization. The model is trained on stellar masses for evolved stars derived from asteroseismology and predicts the relationship between the carbon and nitrogen abundances of a given star and its age. Unlike standard neural network techniques, normalizing flows enable the recovery of full likelihood distributions for individual stellar ages, offering a richer and more informative perspective on uncertainties. Our method yields age estimations for 378,720 evolved stars and achieves a typical absolute age uncertainty of approximately 2 Gyr. By intrinsically accounting for the coverage and density of the training data, our model ensures that the resulting uncertainties reflect both the inherent noise in the data and the completeness of the sampled parameter space. Applying this method to data from the fifth-generation Sloan Digital Sky Survey Milky Way Mapper, we have produced the largest stellar age catalog for evolved stars to date.

Keywords: Stellar astronomy, Galactic archaeology, Stellar ages
The JDISC Survey: Linking the Physics and Chemistry of Inner and Outer Protoplanetary Disk Zones. Mid-infrared spectroscopy of protoplanetary disks provides a chemical inventory of gas within a few astronomical unit, where planets are readily detected around older stars. With the James Webb Space Telescope (JWST) Disk Infrared Spectral Chemistry Survey, we explore demographic trends among 31 disks observed with MIRI (MRS) and with previous Atacama Large Millimeter/submillimeter Array millimeter continuum imaging at high angular resolution (5─10 au). With these signal-to-noise ratio of ∼200─450 spectra, we report emission from H2O, OH, CO, C2H2, HCN, CO2, [Ne II], [Ne III], and [Ar II]. Emission from H2O, OH, and CO is nearly ubiquitous for low-mass stars, and detection rates of all molecules are higher than for similar disks observed with Spitzer-IRS. Slab model fits to the molecular emission lines demonstrate that emission from C2H2, HCN, and possibly CO2 is optically thin; thus since column densities and emitting radii are degenerate, observations are actually sensitive to the total molecular mass. C2H2 and HCN emission also typically originate in a hotter region ( 920−130+70 ,  820−130+70  K, respectively) than CO2 ( 600−160+200  K). The HCN to cold H2O luminosity ratios are generally smaller in smooth disks, consistent with more efficient water delivery via icy pebbles in the absence of large dust substructures. The molecular emission-line luminosities are also correlated with mass accretion rates and infrared spectral indices, similar to trends reported from Spitzer-IRS surveys. This work demonstrates the power of combining multiwavelength observations to explore inner disk chemistry as a function of outer disk and stellar properties, which will continue to grow as the sample of observed Class II systems expands in the coming JWST observation cycles.

Keywords: Infrared spectroscopy, Planetary system formation, James Webb Space Telescope, Protoplanetary disks, Small molecules
Eleven New Transiting Brown Dwarfs and Very-low-mass Stars from TESS. We present the discovery of 11 new transiting brown dwarfs (BDs) and low-mass M dwarfs from NASA's Transiting Exoplanet Survey Satellite (TESS) mission: TOI-2844, TOI-3122, TOI-3577, TOI-3755, TOI-4462, TOI-4635, TOI-4737, TOI-4759, TOI-5240, TOI-5467, and TOI-5882. They consist of five BD companions and six very-low-mass stellar companions ranging in mass from 25 MJ to 128 MJ. We used a combination of photometric time-series, spectroscopic, and high-resolution imaging follow-up as a part of the TESS Follow-up Observing Program (or TFOP) to characterize each system. With over 50 transiting BDs confirmed, we now have a large enough sample to directly test different formation and evolutionary scenarios. We provide a renewed perspective on the transiting "brown dwarf desert" and its role in differentiating between planetary and stellar formation mechanisms. Our analysis of the eccentricity distribution for the transiting BD sample does not support previous claims of a transition between planetary and stellar formation at ∼42 MJ. We also contribute a first look into the metallicity distribution of transiting companions in the range 7─150 MJ, showing that this does not support a ∼42 MJ transition too. Finally, we also detect a significant lithium absorption feature in one of the BD hosts (TOI-5882). However, we determine that the host star is likely old based on rotation, kinematic, and photometric mdeasurements. We therefore claim that TOI-5882 may be a candidate for planetary engulfment.

Keywords: M dwarf stars, Brown dwarfs, Transits, Exoplanets, Radial velocity
A Detailed Investigation of HD 209458 b HST and JWST Transmission Spectra with SANSAR. HD 209458 b is the first exoplanet on which an atmosphere was detected. Since then, its atmosphere has been investigated using multiple telescopes and instruments. However, many of its atmospheric constraints remain debatable. While Hubble Space Telescope (HST) observations suggested a highly subsolar metallicity, recent JWST NIRCam observations by Q. Xue et al. constrained a supersolar metallicity with highly subsolar C/O. In this work, we show a detailed investigation of HD 209458 b transmission spectra observations from JWST and HST using SANSAR, a newly developed planetary atmosphere modeling framework, with free, equilibrium chemistry and self-consistent grid retrievals. The overall best-fitting model with free retrievals ( χred2  = 1.21) constrains its metallicity and C/O to be highly subsolar, while equilibrium chemistry and grid retrievals ( χred2  = 1.27 and 1.30, respectively) are consistent with solar values using Space Telescope Imaging Spectrograph (STIS)+WFC3+NIRCam observations. The retrieved abundances of H2O and CO2 are almost 3 orders of magnitude lower (highly subsolar) with STIS+WFC3+NIRCam compared to just NIRCam, using free retrievals. NIRCam observations alone also result in misleading constraints on metallicity and C/O, with equilibrium chemistry and grid retrieval. We find that the model choice of varying C/H or O/H to vary the C/O in equilibrium chemistry retrievals leads to different metallicity constraints with NIRCam, but similar constraints with STIS+WFC3+NIRCam. We conclude that NIRCam observations alone can lead to overestimation of abundances for exoplanet atmospheres and, therefore, should be used in combination with UV/optical and near-infrared observations to obtain robust constraints on abundances, C/O, and metallicity. In particular, even though we can detect the CO2 feature with just NIRCam, we cannot constrain its abundances robustly without the optical baseline.

Keywords: Hot Jupiters, Exoplanet atmospheres, Transmission spectroscopy