Sazuna/UAT_keywords huggingface dataset:
A Tendency Toward Alignment in Single-star Warm-Jupiter Systems. The distribution of spin-orbit angles for systems with wide-separation, tidally detached exoplanets offers a unique constraint on the prevalence of dynamically violent planetary evolution histories. Tidally detached planets provide a relatively unbiased view of the primordial stellar obliquity distribution, as they cannot tidally realign within the system lifetime. We present the third result from our Stellar Obliquities in Long-period Exoplanet Systems (SOLES) survey: a measurement of the Rossiter-McLaughlin effect across two transits of the tidally detached warm Jupiter TOI-1478 b with the WIYN/NEID and Keck/HIRES spectrographs, revealing a sky-projected spin-orbit angle $\lambda ={6.2}_{-5.5}^{+5.9^\circ} $ . Combining this new measurement with the full set of archival obliquity measurements, including two previous constraints from the SOLES survey, we demonstrate that, in single-star systems, tidally detached warm Jupiters are preferentially more aligned than closer-orbiting hot Jupiters. This finding has two key implications: (1) planets in single-star systems tend to form within aligned protoplanetary disks, and (2) warm Jupiters form more quiescently than hot Jupiters, which, in single-star systems, are likely perturbed into a misaligned state through planet-planet interactions in the post-disk-dispersal phase. We also find that lower-mass Saturns span a wide range of spin-orbit angles, suggesting a prevalence of planet-planet scattering and/or secular mechanisms in these systems.

Keywords: Exoplanet dynamics, Planetary theory, Exoplanets, Planetary alignment, Hot Jupiters, Exoplanet systems, Exoplanet astronomy, Exoplanet evolution, Protoplanetary disks, Star-planet interactions, Planetary dynamics
Gap Opening and Inner Disk Structure in the Strongly Accreting Transition Disk of DM Tau. Large inner dust gaps in transition disks are frequently posited as evidence of giant planets sculpting gas and dust in the disk, or the opening of a gap by photoevaporative winds. Although the former hypothesis is strongly supported by the observations of planets and deep depletions in gas within the gap in some disks, many T Tauri stars hosting transition disks accrete at rates typical for an undepleted disk, raising the question of how gap opening occurs in these objects. We thus present an analysis of the structure of the transition disk around the T Tauri star DM Tau, which is strongly accreting (~10-8.3 M ⊙ yr-1) and turbulent (α = 0.078 ± 0.02). Using the Dust And LInes thermochemical code, we fit disk models to simultaneously reproduce the accretion rate, high level of turbulence, the gas traced by ALMA Band 6 observations of 12CO, 13CO, and C18O J = 2-1 lines, and the observed dust emission from the millimeter continuum and spectral energy distribution. We find a shallow depletion in gas surface density of ~10 relative to the outer disk and a gas-rich inner disk that is consistent with the observations. The planet mass of &lt;1 M Jup implied by the gap depth is in tension with predictions for dust trapping in a highly viscous disk, which requires a more massive planet of ~10 M Jup. Photoevaporative models including a dead zone can qualitatively reproduce some features of the DM Tau disk, but still struggle to explain the high accretion rates and the observed millimeter-continuum flux.

Keywords: Planetary-disk interactions, Millimeter astronomy, Astrochemistry, Planetary system formation, Star formation, Protoplanetary disks, Stellar accretion disks, Planet formation
Inhomogeneity within Local Interstellar Clouds. Analysis of interstellar absorption lines observed in high-resolution Hubble Space Telescope spectra of nearby stars provides temperatures, turbulent velocities, and kinetic properties of warm interstellar clouds. A new analysis of 97 interstellar-velocity components reveals a wide range of temperatures and turbulent velocities within the Local Interstellar Cloud (LIC) and the nearby Cluster of Interstellar Clouds (CLIC). These variations appear to be random with Gaussian distributions. We find no trends of these properties with stellar distance or angles from the Galactic Center, magnetic field, the main source of extreme-UV radiation (the star ϵ CMa), the center of the LIC, or the direction of inflowing interstellar matter into the heliosphere. The spatial scale for temperature variations in the LIC is likely smaller than 5100 au, a distance that the Sun will traverse in 1000 yr. Essentially all velocity components align with known warm clouds. We find that within 4 pc of the Sun, space is completely filled with partially ionized clouds, but at larger distances space is only partially filled with partially ionized clouds. We find that the neutral hydrogen number density in the LIC and likely other warm clouds in the CLIC is about 0.10 cm-3 rather than the 0.20 cm-3 density that may be representative of only the immediate environment of the LIC. The ≤3000-12,000 K temperature range for the gas is wider than the predictions of thermal equilibrium theoretical models of the warm neutral medium and warm ionized medium, and the high degree of inhomogeneity within clouds argues against simple theoretical models. *All of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute. The specific observations analyzed can be accessed via https://doi.org/10.17909/gabn-m136. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support to MAST for these data is provided by the NASA office of Space Science via grant No. NAG5-7584 and by other grants and contracts.

Keywords: Interstellar magnetic fields, Ultraviolet sources, Interstellar clouds, Interstellar dynamics
Reduced Variations in Earth's and Mars' Orbital Inclination and Earth's Obliquity from 58 to 48 Myr ago due to Solar System Chaos. The dynamical evolution of the solar system is chaotic with a Lyapunov time of only ~5 Myr for the inner planets. Due to the chaos it is fundamentally impossible to accurately predict the solar system's orbital evolution beyond ~50 Myr based on present astronomical observations. We have recently developed a method to overcome the problem by using the geologic record to constrain astronomical solutions in the past. Our resulting optimal astronomical solution (called ZB18a) shows exceptional agreement with the geologic record to ~58 Ma (Myr ago) and a characteristic resonance transition around 50 Ma. Here we show that ZB18a and integration of Earth's and Mars' spin vector based on ZB18a yield reduced variations in Earth's and Mars' orbital inclination and Earth's obliquity (axial tilt) from ~58 to ~48 Ma-the latter being consistent with paleoclimate records. The changes in the obliquities have important implications for the climate histories of Earth and Mars. We provide a detailed analysis of solar system frequencies (g and s modes) and show that the shifts in the variation in Earth's and Mars' orbital inclination and obliquity around 48 Ma are associated with the resonance transition and caused by changes in the contributions to the superposition of s modes, plus g-s mode interactions in the inner solar system. The g-s mode interactions and the resonance transition (consistent with geologic data) are unequivocal manifestations of chaos. Dynamical chaos in the solar system hence not only affects its orbital properties but also the long-term evolution of planetary climate through eccentricity and the link between inclination and axial tilt.

Keywords: Solar system, Celestial mechanics, Planetary climates, Orbital theory, Dynamical evolution
Solar Coronal Mass Ejections Plasma Diagnostics Expressed as Potential Stellar CME Signatures. Solar coronal mass ejections (CMEs) have a strong association with solar flares that is not fully understood. This characteristic of our Sun's magnetic activity may also occur on other stars, but the lack of successfully detected stellar CMEs makes it difficult to perform statistical studies that might show a similar association between CMEs and flares. Because of the potentially strong association, the search for stellar CMEs often starts with a successful search for superflares on magnetically active stars. Regardless of the flare's presence, we emphasize the utility of searching for CME-specific spectroscopic signatures when attempting to find and confirm stellar CME candidates. We use solar CMEs as examples of why a multitude of ultraviolet emission lines, when detected simultaneously, can substantially improve the credibility of spectroscopically discovered stellar CME candidates. We make predictions on how bright CME-related emission lines can be if they are derived from distant stars. We recommend the use of three emission lines in particular (C IV 1550 Å, O VI 1032 Å, and C III 977 Å) due to their potentially bright signal and convenient diagnostic capabilities that can be used to confirm if an observational signature truly derives from a stellar CME.

Keywords: Stellar phenomena, Solar coronal mass ejections, Stellar coronal mass ejections
Gemini-LIGHTS: Herbig Ae/Be and Massive T Tauri Protoplanetary Disks Imaged with Gemini Planet Imager. We present the complete sample of protoplanetary disks from the Gemini- Large Imaging with the Gemini Planet Imager Herbig/T Tauri Survey, which observed bright Herbig Ae/Be stars and T Tauri stars in near-infrared polarized light to search for signatures of disk evolution and ongoing planet formation. The 44 targets were chosen based on their near- and mid-infrared colors, with roughly equal numbers of transitional, pre-transitional, and full disks. Our approach explicitly did not favor well-known, "famous" disks or those observed by the Atacama Large Millimeter/submillimeter Array, resulting in a less-biased sample suitable to probe the major stages of disk evolution during planet formation. Our optimized data reduction allowed polarized flux as low as 0.002% of the stellar light to be detected, and we report polarized scattered light around 80% of our targets. We detected point-like companions for 47% of the targets, including three brown dwarfs (two confirmed, one new), and a new super-Jupiter-mass candidate around V1295 Aql. We searched for correlations between the polarized flux and system parameters, finding a few clear trends: the presence of a companion drastically reduces the polarized flux levels, far-IR excess correlates with polarized flux for nonbinary systems, and systems hosting disks with ring structures have stellar masses &lt;3 M☉. Our sample also included four hot, dusty "FS CMa" systems, and we detected large-scale ( &gt;100 au) scattered light around each, signs of extreme youth for these enigmatic systems. Science-ready images are publicly available through multiple distribution channels using a new FITS file standard that has been jointly developed with members of the Very Large Telescope Spectro-polarimetric High-contrast Exoplanet Research team.

Keywords: Herbig Ae/Be stars, Exoplanets, Direct imaging, Protoplanetary disks, Circumstellar dust
AU Microscopii in the Far-UV: Observations in Quiescence, during Flares, and Implications for AU Mic b and c. High-energy X-ray and ultraviolet (UV) radiation from young stars impacts planetary atmospheric chemistry and mass loss. The active ~22 Myr M dwarf AU Mic hosts two exoplanets orbiting interior to its debris disk. Therefore, this system provides a unique opportunity to quantify the effects of stellar X-ray and UV irradiation on planetary atmospheres as a function of both age and orbital separation. In this paper, we present over 5 hr of far-UV (FUV) observations of AU Mic taken with the Cosmic Origins Spectrograph (COS; 1070-1360 Å) on the Hubble Space Telescope (HST). We provide an itemization of 120 emission features in the HST/COS FUV spectrum and quantify the flux contributions from formation temperatures ranging from 104 to 107 K. We detect 13 flares in the FUV white-light curve with energies ranging from 1029 to 1031 erg s. The majority of the energy in each of these flares is released from the transition region between the chromosphere and the corona. There is a 100× increase in flux at continuum wavelengths λ &lt; 1100 Å in each flare, which may be caused by thermal Bremsstrahlung emission. We calculate that the baseline atmospheric mass-loss rate for AU Mic b is ~108 g s-1, although this rate can be as high as ~1014 g s-1 during flares with ${L}_{\mathrm{flare}}\simeq {10}^{33}$ erg s-1. Finally, we model the transmission spectra for AU Mic b and c with a new panchromatic spectrum of AU Mic and motivate future JWST observations of these planets.

Keywords: M dwarf stars, Hubble Space Telescope, Stellar activity, Ultraviolet astronomy, Stellar flares, Exoplanet atmospheres
Analytic Light Curve for Mutual Transits of Two Bodies Across a Limb-darkened Star. We present a solution for the light curve of two bodies mutually transiting a star with polynomial limb darkening. The term "mutual transit" in this work refers to a transit of the star during which overlap occurs between the two transiting bodies. These could be an exoplanet with an exomoon companion, two exoplanets, an eclipsing binary and a planet, or two stars eclipsing a third in a triple-star system. We include analytic derivatives of the light curve with respect to the positions and radii of both bodies. We provide code that implements a photodynamical model for a mutual transit. We include two dynamical models, one for hierarchical systems in which a secondary body orbits a larger primary (e.g., an exomoon system) and a second for confocal systems in which two bodies independently orbit a central mass (e.g., two planets in widely separated orbits). Our code is fast enough to enable inference with Markov Chain Monte Carlo algorithms, and the inclusion of derivatives allows for the use of gradient-based inference methods such as Hamiltonian Monte Carlo. While applicable to a variety of systems, this work was undertaken primarily with exomoons in mind. It is our hope that making this code publicly available will reduce barriers for the community to assess the detectability of exomoons, conduct searches for exomoons, and attempt to validate existing exomoon candidates. We also anticipate that our code will be useful for studies of planet-planet transits in exoplanetary systems, transits of circumbinary planets, and eclipses in triple-star systems.

Keywords: Exoplanet dynamics, Multiple stars, Natural satellites (Extrasolar), Binary stars, Exoplanets, Exoplanet systems, Exoplanet astronomy, Planet hosting stars, Exoplanet detection methods, Trinary stars
Mass-Velocity Dispersion Relation by Using the Gaia Data and Its Effect on Interpreting Short-duration and Degenerate Microlensing Events. Gravitational microlensing, the lensing of stars in the Milky Way with other stars, has been used for exploring compact dark matter objects, exoplanets, and black holes. The duration of microlensing events, the so-called Einstein crossing time, is a function of distance, mass, and velocities of lens objects. Lenses with different ages and masses might have various characteristic velocities inside the Galaxy and this might lead to our misinterpretation of microlensing events. In this work, we use the Gaia archived data to find a relation between the velocity dispersion and mass, and the age of stars. This mass-velocity dispersion relation confirms the known age-velocity relation for early-type and massive stars, and additionally reveals a dependence of stellar velocity dispersion on the mass for low-mass and late-type stars at a 2σ-3σ level. By considering this correlation, we simulate short-duration microlensing events due to brown dwarfs. From this simulation, we conclude that lens masses are underestimated by ~2.5%-5.5% while modeling short-duration and degenerate microlensing events with the Bayesian analysis.

Keywords: Gravitational microlensing, Gravitational microlensing exoplanet detection, Stellar types
A Taxonomy for the Configurations of Quadruply Lensed Quasars. A simple, novice-friendly scheme for classifying the image configurations of quadruply lensed quasars is proposed. With only six classes, it is intentionally coarse grained. It focuses on the kitelikeness and circularity of these configurations, or the absence thereof. Other features are deliberately ignored, their importance to professional astronomers notwithstanding. Readers are invited to test drive the scheme on a sample of 12 quadruply lensed quasar systems. The theoretical underpinnings of the scheme are described in a technical appendix.

Keywords: Strong gravitational lensing, Quasars
The Infrared Medium-deep Survey. IX. Discovery of Two New z   6 Quasars and Space Density Down to M <SUB>1450</SUB>   -23.5 mag. We present the result of the Infrared Medium-deep Survey (IMS) z ~ 6 quasar survey, using the combination of the IMS near-infrared images and the Canada-France-Hawaii Telescope Legacy Survey optical images. The traditional color selection method results in 25 quasar candidates over 86 deg2. We introduce the corrected Akaike information criterion (AICc) with the high-redshift quasar and late-type star models to prioritize the candidates efficiently. Among the color-selected candidates, seven plausible candidates finally passed the AICc selection, of which three are known quasars at z ~ 6. The follow-up spectroscopic observations for the remaining four candidates were carried out, and we confirmed that two out of four are z ~ 6 quasars. With this complete sample, we revisited the quasar space density at z ~ 6 down to M 1450 ~ -23.5 mag. Our result supports the low quasar space density at the luminosity where the quasar's ultraviolet ionizing emissivity peaks, favoring a minor contribution of quasars to the cosmic reionization.

Keywords: Observational astronomy, Early universe, Sky surveys, Quasars, Active galactic nuclei, Reionization
TESS Hunt for Young and Maturing Exoplanets (THYME). VII. Membership, Rotation, and Lithium in the Young Cluster Group-X and a New Young Exoplanet. The public, all-sky surveys Gaia and TESS provide the ability to identify new young associations and determine their ages. These associations enable study of planetary evolution by providing new opportunities to discover young exoplanets. A young association was recently identified by Tang et al. and Fürnkranz et al. using astrometry from Gaia (called "Group-X" by the former). In this work, we investigate the age and membership of this association, and we validate the exoplanet TOI 2048 b, which was identified to transit a young, late G dwarf in Group-X using photometry from TESS. We first identified new candidate members of Group-X using Gaia EDR3 data. To infer the age of the association, we measured rotation periods for candidate members using TESS data. The clear color-period sequence indicates that the association is the same age as the 300 ± 50 Myr old NGC 3532. We obtained optical spectra for candidate members that show lithium absorption consistent with this young age. Further, we serendipitously identify a new, small association nearby Group-X, which we call MELANGE-2. Lastly, we statistically validate TOI 2048 b, which is a 2.1 ± 0.2 R ⊕ radius planet on a 13.8-day orbit around its 300 Myr old host star.

Keywords: Stellar rotation, Young star clusters, Exoplanets
A Search for Radio Technosignatures at the Solar Gravitational Lens Targeting Alpha Centauri. Stars provide an enormous gain for interstellar communications at their gravitational focus, perhaps as part of an interstellar network. If the Sun is part of such a network, there should be probes at the gravitational foci of nearby stars. If there are probes within the solar system connected to such a network, we might detect them by intercepting transmissions from relays at these foci. Here, we demonstrate a search across a wide bandwidth for interstellar communication relays beyond the Sun's innermost gravitational focus at 550 au using the Green Bank Telescope (GBT) and Breakthrough Listen (BL) backend. As a first target, we searched for a relay at the focus of the Alpha Centauri AB system while correcting for the parallax due to Earth's orbit around the Sun. We searched for radio signals directed at the inner solar system from such a source in the L and S bands. Our analysis, utilizing the turboSETI software developed by BL, did not detect any signal indicative of a non-human-made artificial origin. Further analysis excluded false negatives and signals from the nearby target HD 13908. Assuming a conservative gain of 103 in the L band and roughly 4 times that in the S band, a ~1 m directed transmitter would be detectable by our search above 7 W at 550 au or 23 W at 1000 au in the L band, and above 2 W at 550 au or 7 W at 1000 au in the S band. Finally, we discuss the application of this method to other frequencies and targets.

Keywords: Technosignatures, Gravitational lensing, Radio astronomy
Searching the SETI Ellipsoid with Gaia. The search for extraterrestrial intelligence (SETI) Ellipsoid is a geometric method for prioritizing technosignature observations based on the strategy of receiving signals synchronized to conspicuous astronomical events. Precise distances to nearby stars from Gaia makes constraining Ellipsoid crossing times possible. Here we explore the utility of using the Gaia Catalog of Nearby Stars to select targets on the SN 1987A SETI Ellipsoid, as well as the Ellipsoids defined by 278 classical novae. Less than 8% of stars within the 100 pc sample are inside the SN 1987A SETI Ellipsoid, meaning the vast majority of nearby stars are still viable targets for monitoring over time. We find an average of 734 stars per year within the 100 pc volume will intersect the Ellipsoid from SN 1987A, with ~10% of those having distance uncertainties from Gaia better than 0.1 lyr.

Keywords: Search for extraterrestrial intelligence, Technosignatures
Constraining the Planet Occurrence Rate around Halo Stars of Potentially Extragalactic Origin. The search for planets orbiting other stars has recently expanded to include stars from galaxies outside the Milky Way. With the Transiting Exoplanet Survey Satellite (TESS) and Gaia surveys, photometric and kinematic information can be combined to identify transiting planet candidates of extragalactic origin. Here, 1080 low-luminosity red-giant branch stars observed by Gaia and TESS with kinematics suggesting a high likelihood of extragalactic origin were searched for planet transits. Transit injection-recovery tests were performed to measure the sensitivity of the TESS data and completeness of the transit search. Injected signals of planets larger than Jupiter with orbital periods of 10 days or less were recovered in ≈44% of cases. Although no planet transits were detected in this sample, we find an upper limit on planet occurrence of 0.52% for hot Jupiters, consistent with previous studies of planet occurrence around similar host stars. As stars in the halo tend to be lower metallicity, and short-period giant planet occurrence tends to be strongly correlated with stellar metallicity, we predict that relative to the Galactic disk population, a smaller fraction of halo stars will host planets detectable by transit surveys. Thus, applying the known planet occurrence trends to potential planet detection around halo stars, we predict ≳13,000 stars must be searched with similar cadence and precision as the stars studied here before a detection of a planet of extragalactic origin is likely. This may be possible with future data releases from the TESS and Gaia missions.

Keywords: Halo stars, Exoplanets, Red giant stars