Sazuna/UAT_keywords huggingface dataset:
Atmospheric Distribution and Escape of Odd Nitrogen on Mars. The total nitrogen budget in the Martian upper atmosphere is significantly contributed by the presence of odd nitrogen, mainly in the form of NO and ground-state or excited-state N. The distribution of these species can be effectively probed by airglow emission on Mars, and understanding such a distribution is crucial for unveiling the thermal balance in the Martian upper atmosphere. In this study, we construct a sophisticated 1D photochemical model that also incorporates vertical diffusion and photoelectron production and transport. Such a model is used for obtaining the atmospheric distribution of both NO and different electronic states of atomic N on the dayside of Mars. Our study reproduces well the available measurements of relevant species in the combined Martian upper atmosphere and ionosphere, disentangling various chemical pathways in their contributions to odd nitrogen production and destruction. In addition, the photochemical model is combined with a Monte Carlo kinetic model to derive the dayside total N escape rate to be 3.3 × 1023 s‑1 driven by photochemistry. This study corroborates previous findings that N2 photolysis and N  dissociative recombination are the main contributors to the photochemical escape of N on Mars. Moreover, it underscores the significant role of photochemistry in shaping the long-term evolution of the Martian atmosphere.

Keywords: Planetary ionospheres, Mars, Planetary atmospheres, Solar system terrestrial planets, Atmospheric composition
TESS Giants Transiting Giants. VII. A Hot Saturn Orbiting an Oscillating Red Giant Star. We present the discovery of TOI-7041 b (TIC 201175570b), a hot Saturn transiting a red giant star with measurable stellar oscillations. We observe solar-like oscillations in TOI-7041 with a frequency of maximum power of  218.50±2.23 μHz and a large frequency separation of ∆ν = 16.5282±0.0186 μHz. Our asteroseismic analysis indicates that TOI-7041 has a mass of 1.07±0.05(stat)±0.02(sys) M⊙ and a radius of 4.10 ± 0.06(stat)±0.05(sys) R⊙, making it one of the largest stars around which a transiting planet has been discovered with the Transiting Exoplanet Survey Satellite (TESS), and the mission's first oscillating red giant with a transiting planet. TOI-7041 b has an orbital period of 9.691±0.006 days and a low eccentricity of e = 0.04 ± 0.04. We measure a planet radius of 1.02 ± 0.03 RJup with TESS photometry, and a planet mass of 0.36±0.16 MJup (114±51 M⊕) with ground-based radial velocity measurements. TOI-7041 b appears less inflated than similar systems receiving equivalent incident flux, and its circular orbit indicates that it is not undergoing tidal heating due to circularization. The asteroseismic analysis of the host star provides some of the tightest constraints on the stellar properties of a TESS planet host and enables precise characterization of the hot Saturn. This system joins a small number of TESS-discovered exoplanets orbiting stars that exhibit clear stellar oscillations and indicates that extended TESS observations of evolved stars will similarly provide a path to improved exoplanet characterization. *This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Keywords: Hot Jupiters, Late stellar evolution, Exoplanets, Red giant stars, Exoplanet detection methods, Transit photometry, Asteroseismology, Stellar evolution
Demographics of M Dwarf Binary Exoplanet Hosts Discovered by TESS. M dwarfs have become increasingly important in the detection of exoplanets and the study of Earth-sized planets and their habitability. However, 20%─30% of M dwarfs have companions that can impact the formation and evolution of planetary systems. We use high-resolution imaging and Gaia astrometry to detect stellar companions around M dwarf exoplanet hosts discovered by TESS and determine the projected separation and estimated stellar masses for each system. We find 47 companions around 216 M dwarfs and a multiplicity rate of 19.4% ± 2.7% that is consistent with field M dwarfs. The binary projected separation distribution is shifted to larger separations, confirming the lack of close binaries hosting transiting exoplanets seen in previous studies. We correct the radii of planets with nearby companions and examine the properties of planets in M dwarf multistar systems. We also note three multiplanet systems that occur in close binaries (≲50 au) where planet formation is expected to be suppressed.

Keywords: M dwarf stars, Low mass stars, Binary stars, Exoplanet systems
SDSS J100711.74+193056.2: A Candidate Common Motion Substellar Companion to the Nearest B-type Star Regulus. The L9 dwarf SDSS J100711.74+193056.2 is situated 7 5 north of the nearest B-type star Regulus (d = 24.3 ± 0.2 pc), part of a stellar quadruplet. The object is at similar distance (d = 21.9 ± 1.0 pc) as Regulus, with a 3D separation of   pc (~1.6 tidal radii from Regulus), and shares tangential motion within 2 km s‑1, hinting at a physical connection. Near-infrared spectroscopy with Keck/NIRES finds that SDSS J100711.74+193056.2 also has a comparable radial velocity as Regulus A and B, a metallicity similar to Regulus B, and a spectral morphology consistent with the estimated 1–2 Gyr total age of Regulus's close pre-white-dwarf companion. Taken together, these observations indicate that SDSS J100711.74+193056.2 is a very widely separated and potentially physically bound companion to Regulus, with a binding energy and mass ratio comparable to other wide star-brown dwarf systems. It joins a growing list of brown dwarfs at the L-dwarf/T-dwarf transition with independent constraints on physical properties such as age and metallicity.

Keywords: Wide binary stars, Multiple stars, L dwarfs, T dwarfs
Predicting Interstellar Object Chemodynamics with Gaia. The interstellar object (ISO) population of the Milky Way is a product of its stars. However, what is in fact a complex structure in the solar neighborhood has traditionally in ISO studies been described as smoothly distributed. Using a debiased stellar population derived from the Gaia Data Release 3 stellar sample, we predict that the velocity distribution of ISOs is far more textured than a smooth Gaussian. The moving groups caused by Galactic resonances dominate the distribution. 1I/'Oumuamua and 2I/Borisov have entirely normal places within these distributions; 1I is within the noncoeval moving group that includes the Matariki (Pleiades) cluster, and 2I within the Coma Berenices moving group. We show that for the composition of planetesimals formed beyond the ice line, these velocity structures also have a chemodynamic component. This variation will be visible on the sky. We predict that this richly textured distribution will be differentiable from smooth Gaussians in samples that are within the expected discovery capacity of the Vera C. Rubin Observatory. Solar neighborhood ISOs will be of all ages and come from a dynamic mix of many different populations of stars, reflecting their origins from all around the Galactic disk.

Keywords: Galaxy dynamics, Interstellar objects, Milky Way Galaxy
Detecting Planetary Oblateness in the Era of JWST: A Case Study of Kepler-167e. Planets may be rotationally flattened, and their oblateness thus provides useful information on their formation and evolution. Here, we develop a new algorithm that can compute the transit light curve due to an oblate planet very efficiently and use it to study the detectability of planet oblateness (and spin obliquity) with the James Webb Space Telescope (JWST). Using the Jupiter analog, Kepler-167e, as an example, we show that observations of a single transit with JWST are able to detect a Saturn-like oblateness (f = 0.1) with high confidence, or set a stringent upper limit on the oblateness parameter, as long as the planetary spin is slightly misaligned (≳20°) with respect to its orbital direction. Based on known obliquity measurements and theoretical arguments, it is reasonable to believe that this level of misalignment may be common. We estimate the sensitivity limit of JWST in oblateness detections and highlight the importance of better characterizations of cold planets in planning future JWST transit observations. The potential to detect rings, moons, and atmospheric species of the cold giants with JWST is also discussed.

Keywords: Transit photometry, Oblateness, Exoplanets
Mon R2: A Hub─Filament System with an Infrared Bubble at the Hub Center. A multiwavelength, multiscale study of the Mon R2 hub─filament system (HFS) reveals a spiral structure, with the central hub containing more mass than its filaments. C18O(1─0) emission detected by the Atacama Large Millimeter/submillimeter Array (ALMA) reveals several accreting filaments connected to a molecular ring (size ∼0.18 pc × 0.26 pc). The molecular ring surrounds the infrared (IR) ring (size ~0.12 pc × 0.16 pc), which is not usually observed. The IR ring encircles IR-quiet regions and a population of embedded near-IR sources, including the massive stars IRS 1 and IRS 2. ALMA HNC(3─2) line data reveal a mirrored B-shaped feature (extent ∼19,000 au × 39,000 au) toward the eastern part of the molecular ring, suggesting expansion at ~2.25 km s−1. Distinct HNC substructures in both redshifted and blueshifted velocity components are investigated toward the B-shaped feature. The presence of these braid-like substructures in each velocity component strongly suggests instability in photon-dominated regions. A dusty shell-like feature (extent ~0.04 pc × 0.07 pc; mass ~7 M⊙) hosting IRS 1 is identified in the ALMA 1.14 mm continuum map, centered toward the base of the B-shaped feature. The IR and dense molecular rings are likely shaped by feedback from massive stars, driven by high pressures of between 10−8 and 10−10 dyn cm−2, observed within a 1 pc range of the B0 zero-age main-sequence star powering the ultracompact H II region. Overall, these outcomes support the idea that the Mon R2 HFS transitioned from IR-quiet to IR-bright, driven by the interaction between gas accretion and feedback from massive stars.

Keywords: Interstellar dust extinction, Pre-main sequence stars, Star formation, Interstellar medium, H II regions
On the Age Calibration of Open Clusters Using Red Clump Stars. In this study, we extend the dust-independent Hatzidimitriou relation between cluster age and dB‑R color difference between the red giant branch (RGB) and red clump to younger cluster ages. We perform membership analysis on 14 galactic open clusters using Gaia DR3 astrometry, then compute the difference in color of the RGB and red clump dB‑R using Gaia photometry. We also compute dB‑R for five fields surrounding Small Magellanic Cloud clusters. We find that the trend derived from older clusters does not extrapolate to younger ages and becomes double valued. We confirm that dB‑R is independent of metallicity. Current stellar evolutionary isochrones do not quantitatively reproduce the trend and furthermore predict an increased color gap with a decrease in metallicity that is not echoed in the data. Integrated light models based on current isochrones exaggerate the color change over the ‑0.5 &lt; [Fe/H] &lt; 0 interval at the few-percent level.

Keywords: Hertzsprung Russell diagram, Red giant branch, Stellar ages, Red giant clump, Open star clusters
Lessons from the High-resolution Spectroscopy of AW UMa and ϵ CrA: Is the Lucy Model Valid?. A re-examination of high-resolution spectral monitoring of the W UMa─type binaries AW UMa and ϵ CrA casts doubt on the widely utilized L. B. Lucy model of contact binaries. The detection of the very faint profile of the secondary component in AW UMa leads to a new spectroscopic determination of the mass ratio, qsp = 0.092 ± 0.007, which is close to the previous, medium-resolution spectroscopic result of T. Pribulla &amp; S. M. Rucinski, qsp = 0.101 ± 0.006, and remains substantially different from a cluster of generally accepted photometric results by several authors, concentrated around qph = 0.080 ± 0.005. A survey of binaries with the best-determined values of the mass ratio shows a common tendency for qph &lt; qsp. The tendency for systematically smaller values of qph may result from the overfilling of the primary lobe and underfilling of the secondary lobe relative to the Roche model geometry, as predicted by the K. Stȩpień model. Despite the observed moderate inter-systemic velocities, the photometric Lucy model may remain useful in providing approximate, though biased, results for the mass ratio. A complicating factor in detailed spectral analysis may be the occurrence of Enhanced Spectral-line Perturbations (ESPs) projected over the secondary profiles, appearing in different numbers in the two studied binaries. The ESPs are tentatively identified within the Stȩpień model as collision fronts or fountains of primary-component gas from the circumbinary, energy-carrying flow.

Keywords: Contact binary stars
Eighteen Exoplanet Host Stars from the NPOI Data Archive. During the course of publishing angular diameters from the Navy Precision Optical Interferometer data archive, we found we had data on 17 confirmed exoplanet host stars and 1 exoplanet candidate (HD 20902/α Per). Here, we update our previously published stellar radii with more precise Gaia parallaxes when available, and use our radius and effective temperature measurements to fit each star's mass and age using MIST models. The mass changed by more than 10% for 9 of the 18 stars. Combining our updated masses, radii, and temperatures, we present refined planetary masses as well as habitable zone calculations.

Keywords: Fundamental parameters of stars, Exoplanet astronomy, Optical interferometry, High angular resolution
Hydroxyl Lines and Moonlight: A High Spectral Resolution Investigation of Near-infrared Skylines from Maunakea to Guide Near-infrared Spectroscopic Surveys. Subtracting the changing sky contribution from the near-infrared (NIR) spectra of faint astronomical objects is challenging and crucial to a wide range of science cases such as estimating the velocity dispersions of dwarf galaxies, studying the gas dynamics in faint galaxies, measuring accurate redshifts, and any spectroscopic study of faint targets. Since the sky background varies with time and location, NIR spectral observations, especially those employing fiber spectrometers and targeting extended sources, require frequent sky-only observations for calibration. However, sky subtraction can be optimized with sufficient a priori knowledge of the sky's variability. In this work, we explore how to optimize sky subtraction by analyzing 1075 high-resolution NIR spectra from the Canada─France─Hawaii Telescope's SPIRou on Maunakea, and we estimate the variability of 481 hydroxyl (OH) lines. These spectra were collected during two sets of three nights dedicated to obtaining sky observations every 5.5 minutes. During the first set, we observed how the Moon affects the NIR, which has not been accurately measured at these wavelengths. We suggest accounting for the Moon contribution at separation distances less than 10° when (1) reconstructing the sky using principal component analysis, (2) observing targets at YJHK magnitudes fainter than ∼15, and (3) attempting a sky subtraction better than 1%. We also identified 126 spectral doublets, or OH lines that split into at least two components, at SPIRou's resolution. In addition, we used Lomb─Scargle periodograms and Gaussian process regression to estimate that most OH lines vary on similar timescales, which provides a valuable input for IR spectroscopic survey strategies. The data (https://zenodo.org/records/13363061) and code (https://github.com/FDauphin/spirou-sky-subtraction) developed for this study are publicly available.

Keywords: Calibration, Infrared spectroscopy, Time series analysis, Night sky brightness
Photometric and Spectroscopic Investigations of Three Large Amplitude Contact Binaries. We performed photometric and spectroscopic studies of three large amplitude contact binaries: NSVS 2418361, ATLAS J057.1170+31.2384, and NSVS 7377875. The amplitudes of these three systems' light curves are more than 0.7 mag. We analyzed the light curves using the Wilson─Devinney code to yield physical parameters. The photometric solutions suggested that NSVS 7377875 belongs to an A-subtype contact binary, while the others are classified as W-subtype ones. Furthermore, the mass ratio of NSVS 7377875 is higher than 0.72, so it belongs to H-subtype contact binaries. Since their light curves have unequal height at two maxima, which is called the O'Connell effect, a dark spot on the primary component for each target was required to get a better fit of the light curves. The orbital period investigation shows that the period of NSVS 2418361 is increasing, indicating a mass transfer from the the less massive component to the more massive one, while the other targets exhibit no long-term variation. Our spectral subtraction analysis of LAMOST spectra revealed excess emissions in the Hα line, indicating chromospheric activity in all the three targets. The Gaia distance was applied to estimate the absolute parameters of the three targets, and we obtained their evolutionary state. The relationships between the energy transfer parameter of 76 H-subtype contact binaries and their bolometric luminosity ratios, as well as their contact degree, were presented. We discovered that H-subtype systems have less efficient energy transfer rate, which corresponds to the conclusion proposed by Csizmadia &amp; Klagyivik.

Keywords: Fundamental parameters of stars, Close binary stars, Mass ratio, Eclipsing binary stars, Stellar evolution
JWST-TST DREAMS: A Precise Water Abundance for Hot Jupiter WASP-17b from the NIRISS SOSS Transmission Spectrum. Water has proven to be ubiquitously detected in near-infrared (NIR) transmission spectroscopy observations of hot Jupiter atmospheres, including WASP-17b. However, previous analyses of WASP-17b's atmosphere based upon Hubble Space Telescope (HST) and Spitzer data could not constrain the water abundance, finding that subsolar, supersolar, and bimodal posterior distributions were all statistically valid. In this work, we observe one transit of the hot Jupiter WASP-17b using JWST's Near Infrared Imager and Slitless Spectrograph (NIRISS) Single Object Slitless Spectroscopy (SOSS) mode. We analyze our data using three independent data analysis pipelines, finding excellent agreement between results. Our transmission spectrum shows multiple H2O absorption features and a flatter slope towards the optical than seen in previous HST observations. We analyze our spectrum using both PICASO + Virga forward models and free retrievals. POSEIDON retrievals provide a well-constrained supersolar log(H2O) abundance (−2.96 ), breaking the degeneracy from the previous HST + Spitzer analysis. We verify our POSEIDON results with petitRADTRANS retrievals. Additionally, we constrain the abundance of log(H−), −10.19 , finding that our model including H− is preferred over our model without H− to 5.1 σ. Furthermore, we constrain the log(K) abundance (−8.07 ) in WASP-17b's atmosphere for the first time using space-based observations. Our abundance constraints demonstrate the power of NIRISS SOSS's increased resolution, precision, and wavelength range to improve upon previous NIR space-based results. This work is part of a series of studies by our JWST Telescope Scientist Team (JWST-TST), in which we use Guaranteed Time Observations to perform Deep Reconnaissance of Exoplanet Atmospheres through Multi-instrument Spectroscopy (DREAMS).

Keywords: Exoplanet atmospheric composition , Infrared spectroscopy, Hot Jupiters, Astronomy data analysis, Transmission spectroscopy, James Webb Space Telescope, Exoplanet atmospheres, Near infrared astronomy
Kinematics of Cataclysmic Variables in the Solar Neighborhood in the Gaia Era. Using high-precision astrometric data from Gaia DR3 and updated systemic velocities from the literature, the kinematical properties of cataclysmic variables (CVs) were investigated. By constraining the data according to the total space velocity error and Galactic population class, a reliable sample of data was obtained. Nonmagnetic CVs located in the thin disk have been found to have a total space velocity dispersion of σν = 46.33 ± 4.23 km s−1, indicating that the thin disk CVs with a mean kinematical age of τ = 3.95 ± 0.75 Gyr are much younger than the local thin disk of the Galaxy with τ ~ 6─9 Gyr. Total space velocity dispersions of nonmagnetic CVs belonging to the thin disk component of the Galaxy were found to be σν = 47.67 ± 3.94 and σν = 44.43 ± 4.33 km s−1 for the systems below and above the orbital period gap, respectively, corresponding to kinematical ages of τ = 4.19 ± 0.71 and τ = 3.61 ± 0.74 Gyr. γ velocity dispersions of the thin disk CVs below and above the gap were obtained σγ = 27.52 ± 2.28 and σγ = 25.65 ± 2.44 km s−1, respectively. This study also shows that the orbital period is decreasing with increasing age, as expected from the standard theory. The age-orbital period relation for nonmagnetic thin disk CVs was obtained as dP/dt = −2.09( ± 0.22) × 10−5 s yr−1. However, a significant difference could not be found between the γ velocity dispersions of the systems below and above the gap, which were calculated to be σγ = 27.52 ± 2.28 and σγ = 25.65 ± 2.44 km s−1, respectively.

Keywords: Stellar kinematics, Cataclysmic variable stars, Solar neighborhood
An Ultrafast Image Simulation Technique with Spatially Variable Point-spread Functions. Simulated images are essential in algorithm development and instrument testing for optical telescopes. During real observations, images obtained by optical telescopes are affected by spatially variable point-spread functions (PSFs), a crucial effect requiring accurate simulation. Traditional methods segment images into patches, convolve patches with individual PSFs, and reassemble them as a whole image. Although widely used, these approaches suffer from slow convolution processes and reduced image fidelity due to abrupt PSF transitions between different patches. This paper introduces a novel method for generating simulated images with spatial continuously varying PSFs. Our approach first decomposes original images into PSF basis derived with the principal component analysis method. The entire image is then convolved with this PSF basis to create image basis. Finally, we multiply the coefficients of image basis by the corresponding PSF basis for each pixel and add the multiplication results along each pixel to obtain the final simulated image. Our method could generate high-fidelity simulated images with spatially variable PSFs without boundary artifacts. The method proposed in this paper significantly improves the speed of astronomical image simulation, potentially advancing observational astronomy and instrumental development.

Keywords: Optical telescopes, Astronomical simulations, Neural networks