Sazuna/UAT_keywords huggingface dataset:
PEPSI Investigation, Retrieval, and Atlas of Numerous Giant Atmospheres (PIRANGA). I. The Ubiquity of Fe I Emission and Inversions in Ultrahot Jupiter Atmospheres. We present high-resolution optical emission spectroscopy observations of the ultrahot Jupiters (UHJs) TOI-1431 b and TOI-1518 b using the PEPSI spectrograph on the LBT. We detect emission lines from Fe I with a significance of 5.68σ and 7.68σ for TOI 1431 b and TOI-1518 b, respectively. We also tentatively detect Cr I emission from TOI-1431 b at 4.32σ. For TOI-1518 b, we tentatively detect Ni I, Fe II, and Mg I at significance levels ranging from 3─4σ. Detection of emission lines indicates that both planets possess temperature inversions in their atmospheres, providing further evidence of the ubiquity of stratospheres among UHJs. By analyzing the population of hot Jupiters, we compare models that predict the distribution of planets in the temperature-gravity space, and find a recent global circulation model suite from A. Roth et al. provides a reasonable match to the observed onset of inversions at Teq ∼ 2000 K. The ubiquity of strong Fe I emission lines among UHJs, together with the paucity of detections of TiO, suggest that atomic iron is the dominant optical opacity source in their atmospheres and can be responsible for the inversions.

Keywords: Exoplanet atmospheric composition , Extrasolar gaseous giant planets, Exoplanet atmospheres, Exoplanet atmospheric structure
Deconvolving X-Ray Galaxy Cluster Spectra Using a Recurrent Inference Machine. Recent advances in machine learning algorithms have unlocked new insights in observational astronomy by allowing astronomers to probe new frontiers. In this article, we present a methodology to disentangle the intrinsic X-ray spectrum of galaxy clusters from the instrumental response function. Employing state-of-the-art modeling software and data mining techniques of the Chandra data archive, we construct a set of 100,000 mock Chandra spectra. We train a Recurrent Inference Machine (RIM) to take in the instrumental response and mock observation and output the intrinsic X-ray spectrum. The RIM can recover the mock intrinsic spectrum below the 1σ error threshold; moreover, the RIM reconstruction of the mock observations is indistinguishable from the observations themselves. To further test the algorithm, we deconvolve extracted spectra from the central regions of the galaxy group NGC 1550, known to have a rich X-ray spectrum, and the massive galaxy clusters A1795. Despite the RIM reconstructions consistently remaining below the 1σ noise level, the recovered intrinsic spectra did not align with modeled expectations. This discrepancy is likely attributable to the RIM's method of implicitly encoding prior information within the neural network. This approach holds promise for unlocking new possibilities in accurate spectral reconstructions and advancing our understanding of complex X-ray cosmic phenomena.

Keywords: Galaxy clusters, Galactic and extragalactic astronomy
[PK2008] HalphaJ115927 and IGR J14091-6108: Two New Intermediate Polars Above the Period Gap. This study presents a detailed timing analyses of two cataclysmic variables (CVs), [PK2008] HalphaJ115927 and IGR J14091-6108, utilizing the optical data from the Transiting Exoplanet Survey Satellite. Periods of 7.20 ± 0.02 hr, 1161.49 ± 0.14 s, and 1215.99 ± 0.15 s are presented for [PK2008] HalphaJ115927, and are interpreted as the probable orbital, spin, and beat periods of the system, respectively. The presence of multiple periodic variations suggests that it likely belongs to the intermediate polar (IP) category of magnetic CVs. Interestingly, [PK2008] HalphaJ115927 exhibits a unique and strong periodic modulation at 5.66 ± 0.29 days, which may result from the precession of an accretion disk, similar to the IP TV Col. The detection of a spin signal of 576.63 ± 0.03 s and inferred orbital signal of ∼15.84 hr supports the classification of IGR J14091-6108 as an IP. The identification of such a long orbital period adds a new example to the limited population of long-period IPs. The observed dominant signal at the second harmonic of the orbital frequency also suggests ellipsoidal modulation of the secondary in this system. The observed double-peaked spin pulse profile in [PK2008] HalphaJ115927 likely results from two-pole accretion, where both poles contribute to the spin modulation, and their geometry allows equal visibility of both accreting poles. In contrast, IGR J14091-6108 exhibits a single-peaked sinusoidal like spin pulse, attributed to the changing visibility of the accretion curtains due to a relatively low dipole inclination. The present observations indicate that accretion in both systems occurs predominantly through a disk.

Keywords: Cataclysmic variable stars
Deep Learning-based Identification of CP1 and CP2 Stars from LAMOST DR11. Chemically peculiar (CP) stars, particularly CP1 (metallic-line) and CP2 (magnetic Ap/Bp) stars, are crucial for studying microscopic processes in stellar atmospheres, such as atomic diffusion and magnetic interactions. In this study, we present ODCNNnet, a deep learning-based classification model designed to identify CP1 and CP2 stars from low-resolution spectra. The model achieves an accuracy of 99.81% and a recall of 99.43% for CP1 stars, and an accuracy of 98.82% with a recall of 99.41% for CP2 stars. Applying ODCNNnet to B- to early F-type stars in LAMOST DR11, we identified 33,049 CP1 stars and 5901 CP2 stars, including 5287 newly identified CP1 stars and 1153 newly identified CP2 stars, validated through cross matching with the MKCLASS tool. We further analyzed the stellar parameters of CP stars. The effective temperature (Teff) of CP1 stars ranges from 6000 K to 9000 K, peaking at 7500 K, while CP2 stars span 6000 K to 13,000 K, with peaks near 8900 K and 11,900 K. The surface gravity ( log g) of CP1 stars is concentrated between 3.4 and 4.6 dex, peaking at 3.9 dex, while CP2 stars range from 3.5 to 4.6 dex. The [Fe/H] of CP1 stars is generally between −1.0 and 0.8 dex, peaking around −0.1 dex, whereas CP2 stars exhibit a broader distribution from −1.5 dex to 1.0 dex, with peaks around −0.25 dex and 0.75 dex. This study provides a valuable data set for investigating the physical properties of CP stars and their underlying formation mechanisms.

Keywords: Am stars, Ap stars, Chemically peculiar stars
Simulating Chemical Abundances in the Circumstellar Nebula of the Late Stage Binary RY Scuti. RY Scuti, thought to be a Wolf–Rayet (WR) progenitor, is a massive post-main-sequence binary star system undergoing Roche-lobe overflow (RLOF). SOFIA (+FORCAST) spectroscopy of the inner, ionized region of RY Scuti's double ringed toroidal nebula affirms the previous detection of the well-studied 12.81 μm Ne II forbidden transition and reveals four distinct emission lines, including three previously undetected transitions, S III, Fe III, and S III. Cloudy photoionization modeling of the four neon, sulfur, and iron lines was performed to derive fractional abundances (log( )) of neon at ‑3.19 ± 0.0251, sulfur at ‑3.76 ± 0.0487, and iron at ‑2.23 ± 0.0286. All three species are overabundant with respect to fiducial solar chemical abundances, especially iron. Our analysis suggests that the outer envelope of the primary star in the RY Scuti system is being stripped away via RLOF, leaving helium-rich and hydrogen-poor material visible to observation. This material also exhibits elevated neon, sulfur, and iron fractional abundances, consistent with RY Scuti evolving toward a WR object.

Keywords: Binary stars, Chemical abundances, Stellar atmospheres
A Heliocentric-orbiting Objects Processing System (HOPS) for the Wide Field Survey Telescope: Architecture, Processing Workflow, and Preliminary Results. Wide-field surveys have markedly enhanced the discovery and study of solar system objects. The 2.5 m Wide Field Survey Telescope (WFST) represents the foremost facility dedicated to optical time-domain surveys in the Northern Hemisphere. To fully exploit WFST's capabilities for solar system object detection, we have developed a heliocentric-orbiting objects processing system (HOPS) tailored for identifying these objects. HOPS integrates HelioLinC3D, an algorithm well suited for the WFST survey cadence, characterized by revisiting the same sky field twice on the majority of nights. In this paper, we outline the architecture and processing flow of HOPS. The application of HOPS to the WFST pilot survey data collected between 2024 March and May demonstrates exceptional performance in terms of both temporal efficiency and completeness. A total of 658,489 observations encompassing 38,520 known asteroids have been documented, and 241 newly discovered asteroids have been assigned provisional designations. In particular, 27% of these new discoveries were achieved using merely two observations per night on three nights. The preliminary results not only illuminate the effectiveness of integrating HelioLinC3D within HOPS, but also emphasize the considerable potential contributions of WFST to the field of solar system science.

Keywords: Sky surveys, Small Solar System bodies, Asteroids, Astronomy data analysis, Heliocentric orbit
TOI-2005b: An Eccentric Warm Jupiter in Spin-orbit Alignment. We report the discovery and characterization of TOI-2005 b, a warm Jupiter on an eccentric (e ∼ 0.59), 17.3 days orbit around a Vmag = 9.867 rapidly rotating F-star. The object was detected as a candidate by Transiting Exoplanet Survey Satellite and the planetary nature of TOI-2005 b was then confirmed via a series of ground-based photometric, spectroscopic, and diffraction-limited imaging observations. The planet was found to reside in a low sky-projected stellar obliquity orbit (λ =   degrees) via a transit spectroscopic observation using the Magellan Magellan Inamori Kyocera Echelle spectrograph. TOI-2005 b is one of a few planets known to have a low-obliquity high-eccentricity orbit, which may be the result of high-eccentricity coplanar migration. The planet has a periastron equilibrium temperature of ∼2100 K, similar to some highly irradiated hot Jupiters where atomic metal species have been detected in transmission spectroscopy, and varies by almost 1000 K during its orbit. Future observations of the atmosphere of TOI-2005b can inform us about its radiative timescales thanks to the rapid heating and cooling of the planet.

Keywords: Exoplanet astronomy, Exoplanets
Refractory and Volatile Species in the UV-to-IR Transmission Spectrum of Ultra-hot Jupiter WASP-178b with HST and JWST. The atmospheres of ultra-hot Jupiters are unique compared to other planets because of the presence of both refractory and volatile gaseous species, enabling a new lens to constrain a planet's composition, chemistry, and formation. WASP-178b is one such ultra-hot Jupiter that was recently found to exhibit enormous near-UV absorption between 0.2 and 0.4 μm from some combination of Fe+, Mg, and SiO. Here, we present new IR observations of WASP-178b with the Hubble Space Telescope (HST) WFC3 and JWST NIRSpec G395H, providing novel measurements of the volatile species H2O and CO in WASP-178b's atmosphere. Atmospheric retrievals find a range of compositional interpretations depending on which data set is retrieved, the type of chemistry assumed, and the temperature structure parameterization used due to the combined effects of thermal dissociation, the lack of volatile spectral features besides H2O and CO, and the relative weakness of H2O and CO themselves. Taken together with a new state-of-the-art characterization of the host star, our retrieval analyses suggests a solar to supersolar [O/H] and [Si/H], but subsolar [C/H], perhaps suggesting rock-laden atmospheric enrichment near the H2O ice line. To obtain meaningful abundance constraints for this planet, it was essential to combine the JWST IR data with short-wavelength HST observations, highlighting the ongoing synergy between the two facilities.

Keywords: Exoplanet atmospheric composition , Stellar ages, Hot Jupiters, Exoplanet astronomy, Infrared astronomy, Exoplanet formation, Exoplanet atmospheres
The Lyα Sky as Observed by New Horizons at 57 au. During 2023 September the Alice ultraviolet spectrograph on the New Horizons (NH) spacecraft was used to map diffuse Lyα emission over most of the sky, at a range of ∼56.9 au from the Sun. At that distance, models predict that the interplanetary medium Lyα emissions result from comparable amounts of resonant backscattering of the solar Lyα line by interstellar hydrogen atoms (H I) passing through the solar system, in addition to an approximately isotropic background of ∼50 ± 20 R from the local interstellar medium (LISM). The NH observations show no strong correlations with nearby cloud structures of the LISM or with expected structures of the heliosphere, such as a hydrogen wall associated with the heliopause. To explain the relatively bright and uniform Lyα of the LISM, we propose that hot, young stars within the Local Hot Bubble shine on its interior walls, photoionizing H I atoms there. Recombination of these ions can account for the observed ∼50 R Lyα background, after amplification of the diffuse Lyα by resonant scattering, although sophisticated (i.e., 3D) radiative transfer models should be used to confirm this conjecture. Future observations of the diffuse Lyα, with instruments capable of resolving the line profile, could provide a new window on H I populations in the LISM and heliosphere. The NH Alice all-sky Lyα observations presented here may be repeated at some point in the future, if resources allow, and the two maps could be combined to provide a significant increase in angular resolution.

Keywords: Interstellar scattering, Interstellar line emission, Interstellar medium
Solar, Dust, and Tidal Effects on Martian Dayside Exospheric Temperature: An Empirical Model Based on a Decadal MAVEN/IUVS Data Set. The Martian exospheric temperature, Texo, is a fundamental parameter that regulates atmospheric escape from Mars to space. Previous studies have shown that this parameter varies significantly in response to both solar forcing and atmospheric dynamics. Accurately quantifying and modeling exospheric temperature is essential for understanding Mars' long-term climate evolution. Using a decadal data set of Lyα airglow emission observed by the Imaging Ultraviolet Spectrograph on the Mars Atmosphere and Volatile EvolutioN mission, we derived the Martian dayside exospheric temperature under varying solar and atmospheric conditions during 2014─2023. Our analysis indicates that the Martian dayside exospheric temperature varies from ∼140 to 300 K over the past decade. Long-term variations are primarily driven by solar forcing, with a sensitivity of ∼45 K mW−1 m2 to the solar Lyα flux measured at Mars. Short-term variations are influenced by dust activity and atmospheric tides. On average, the Martian dayside exospheric temperature is enhanced by ∼20.1 K during large-scale dust storms, and atmospheric tides lead to longitudinal variations with magnitudes of ∼10─15 K and ∼10─30 K near aphelion and perihelion, respectively. We developed an empirical model of the Martian dayside exospheric temperature through multidimensional least-squares fitting, which is capable of capturing the combined effects of solar, dust, and tidal forces. This model offers a valuable tool for estimating the Martian exospheric variability under diverse conditions.

Keywords: Solar cycle, Exosphere, Mars, Planetary atmospheres, Atmospheric tides, Solar activity
A Moderate Albedo from Reflecting Aerosols on the Dayside of WASP-80 b Revealed by JWST/NIRISS Eclipse Spectroscopy. Secondary eclipse observations of exoplanets at near-infrared wavelengths enable the detection of thermal emission and reflected stellar light, providing insights into the thermal structure and aerosol composition of their atmospheres. These properties are intertwined as aerosols influence the energy budget of the planet. WASP-80 b is a warm gas giant with an equilibrium temperature of 825 K orbiting a bright late-K/early-M dwarf, and for which the presence of aerosols in its atmosphere has been suggested from previous Hubble Space Telescope and Spitzer observations. We present an eclipse spectrum of WASP-80 b obtained with JWST NIRISS/SOSS, spanning 0.68–2.83 μm, which includes the first eclipse measurements below 1.1 μm for this exoplanet, extending our ability to probe light reflected by its atmosphere. When a reflected light geometric albedo is included in the atmospheric retrieval, our eclipse spectrum is best explained by a reflected light contribution of ∼30 ppm at short wavelengths, although further observations are needed to statistically confirm this preference. We measure a dayside brightness temperature of   K and constrain the reflected light geometric albedo across the SOSS wavelength range to  , allowing us to estimate a 1σ range for the Bond albedo of 0.148 ≲ AB ≲ 0.383. By comparing our spectrum with aerosol models, we find that manganese sulfide and silicate clouds are disfavored, while cloud species with weak-to-moderate near-infrared reflectance, along with soots or low formation-rate tholin hazes, are consistent with our eclipse spectrum.

Keywords: Exoplanet atmospheric composition , Hot Jupiters, Exoplanets, Extrasolar gaseous giant planets, Exoplanet atmospheres
The Local Ultraviolet to Infrared Treasury. II. Refining Star Formation Histories of 10 Metal-poor Dwarf Galaxies with Simultaneous UV-optical Two-CMD Fitting. We present the star formation histories (SFHs) of 10 metal-poor (≲12% Z⊙), star-forming dwarf galaxies from the Local Ultraviolet to Infrared Treasury survey. The derived SFHs exhibit significant variability, consistent with the irregular star formation expected for dwarf galaxies. Using synthetic near-ultraviolet (UV) and optical color–magnitude diagrams (CMDs) with various yet targeted configurations for dust and input SFHs, we quantitatively demonstrate that simultaneous modeling of the UV and optical CMDs ("UVopt" case) improves the precision of SFH measurements in recent time bins up to ∼1 Gyr, compared to the classical single optical CMD modeling ("Opt-only" case). The UVopt case reduces uncertainties relative to the Opt-only case by ∼4%–8% over the past 10 Myr, ∼8%–20% over 100 Myr, and ∼8%–14% over 1 Gyr, across various dust configurations and input SFHs. Additionally, we demonstrate discrepancies in stellar models for blue core helium-burning (BHeB) stars at the low-metallicity regime. This discrepancy can artificially inflate star formation rate (SFR) estimates in younger age bins by misinterpreting the evolved BHeB stars as reddened upper main-sequence (MS) stars. Incorporating UV data improves BHeB-MS separation and mitigates the limitations of current low-metallicity stellar models. Comparisons of the UVopt SFHs with Hα and far-UV (FUV)-based SFRs reconfirm that Hα is an unreliable tracer over its nominal 10 Myr timescale for low-SFR galaxies, while FUV provides a more reliable tracer but yields SFRFUV values up to twice those of CMD-based &lt;SFR&gt;100 Myr. Our findings underscore the importance of UV data in refining recent SFHs in low-metallicity environments.

Keywords: Dwarf irregular galaxies, Multi-color photometry, Stellar populations, Star formation, Hertzsprung Russell diagram
Early r-process Enrichment and Hierarchical Assembly Across the Sagittarius Dwarf Galaxy. Dwarf galaxies like Sagittarius (Sgr) provide a unique window into the early stages of galactic chemical evolution, particularly through their metal-poor stars. By studying the chemical abundances of stars in the Sgr core and tidal streams, we can gain insights into the assembly history of this galaxy and its early heavy element nucleosynthesis processes. We efficiently selected extremely metal-poor candidates in the core and streams for high-resolution spectroscopic analysis using metallicity-sensitive photometry from SkyMapper DR2 and Gaia DR3 XP spectra, and proper motions. We present a sample of 37 Sgr stars with detailed chemical abundances, of which we identify 10 extremely metal-poor ([Fe/H] ≤ −3.0) stars, 25 very metal-poor ([Fe/H] ≤ −2.0) stars, and two metal-poor ([Fe/H] ≤ −1.0) stars. This sample increases the number of extremely metal-poor Sgr stars analyzed with high-resolution spectroscopy by a factor of 5. Of these stars, 15 are identified as members of the Sgr tidal stream, while the remaining 22 are associated with the core. We derive abundances for up to 20 elements and identify no statistically significant differences between the element abundance patterns across the core and stream samples. Intriguingly, we identify stars that may have formed in ultrafaint dwarf galaxies that accreted onto Sgr, in addition to patterns of C and r-process elements distinct from the Milky Way halo. Over half of the sample shows a neutron-capture element abundance pattern consistent with the scaled solar pure r-process pattern, indicating early r-process enrichment in the Sgr progenitor. *This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Keywords: Galaxy chemical evolution, Stellar abundances, Galactic archaeology, R-process, Chemical enrichment, Sagittarius dwarf spheroidal galaxy
Many Elements Matter: Detailed Abundance Patterns Reveal Star Formation and Enrichment Differences among Milky Way Structural Components. Many nucleosynthetic channels create the elements, but two-parameter models characterized by α and Fe nonetheless predict stellar abundances in the Galactic disk to accuracies of 0.02–0.05 dex for most measured elements, near the level of current abundance uncertainties. It is difficult to make individual measurements more precise than this to investigate lower-amplitude nucleosynthetic effects, but population studies of mean abundance patterns can reveal more subtle abundance differences. Here, we look at the detailed abundances for 67,315 stars from the Apache Point Observatory Galactic Evolution Experiment (or APOGEE) Data Release 17, but in abundance residuals away from a best-fit two-parameter, data-driven nucleosynthetic model. We find that these residuals show complex structures with respect to age, guiding radius, and vertical action that are not random and are also not strongly correlated with sources of systematic error such as  , Teff, and radial velocity. The residual patterns, especially in Na, C+N, Mn, and Ce, trace kinematic structures in the Milky Way, such as the inner disk, thick disk, and flared outer disk. A principal component analysis suggests that most of the observed structure is low-dimensional and can be explained by a few eigenvectors. We find that some, but not all, of the effects in the low-α disk can be explained by dilution with fresh gas, so that the abundance ratios resemble those of stars with higher metallicity. The patterns and maps we provide can be combined with accurate forward models of nucleosynthesis, star formation, and gas infall to provide a more detailed picture of star and element formation in different Milky Way components.

Keywords: Stellar ages, Galaxy chemical evolution, Stellar abundances, Milky Way disk, Galaxy kinematics, Galaxy evolution