Sazuna/UAT_keywords huggingface dataset:
Evidence for the Late Arrival of Hot Jupiters in Systems with High Host-star Obliquities. It has been shown that hot Jupiters systems with massive, hot stellar primaries exhibit a wide range of stellar obliquities. On the other hand, hot Jupiter systems with low-mass, cool primaries often have stellar obliquities close to zero. Efficient tidal interactions between hot Jupiters and the convective envelopes present in lower-mass main-sequence stars have been a popular explanation for these observations. If this explanation is accurate, then aligned systems should be older than misaligned systems. Likewise, the convective envelope mass of a hot Jupiter's host star should be an effective predictor of its obliquity. We derive homogeneous stellar parameters-including convective envelope masses-for hot Jupiter host stars with high-quality sky-projected obliquity inferences. Using a thin-disk stellar population's Galactic velocity dispersion as a relative age proxy, we find that hot Jupiter host stars with larger-than-median obliquities are older than hot Jupiter host stars with smaller-than-median obliquities. The relative age difference between the two populations is larger for hot Jupiter host stars with smaller-than-median fractional convective envelope masses and is significant at the 3.6σ level. We identify stellar mass, not convective envelope mass, as the best predictor of stellar obliquity in hot Jupiter systems. The best explanation for these observations is that many hot Jupiters in misaligned systems arrived in the close proximity of their host stars long after their parent protoplanetary disks dissipated. The dependence of observed age offset on convective envelope mass suggests that tidal realignment contributes to the population of aligned hot Jupiters orbiting stars with convective envelopes.

Keywords: Exoplanet dynamics, Stellar ages, Exoplanets, Stellar kinematics, Exoplanet systems, Exoplanet evolution, Exoplanet tides, Star-planet interactions, Tidal interaction
Transit Timing Variations for AU Microscopii b and c. We explore the transit timing variations (TTVs) of the young (22 Myr) nearby AU Mic planetary system. For AU Mic b, we introduce three Spitzer (4.5 μm) transits, five TESS transits, 11 LCO transits, one PEST transit, one Brierfield transit, and two transit timing measurements from Rossiter-McLaughlin observations; for AU Mic c, we introduce three TESS transits. We present two independent TTV analyses. First, we use EXOFASTv2 to jointly model the Spitzer and ground-based transits and obtain the midpoint transit times. We then construct an O - C diagram and model the TTVs with Exo-Striker. Second, we reproduce our results with an independent photodynamical analysis. We recover a TTV mass for AU Mic c of ${10.8}_{-2.2}^{+2.3}$ M ⊕. We compare the TTV-derived constraints to a recent radial velocity (RV) mass determination. We also observe excess TTVs that do not appear to be consistent with the dynamical interactions of b and c alone or due to spots or flares. Thus, we present a hypothetical nontransiting "middle-d" candidate exoplanet that is consistent with the observed TTVs and candidate RV signal and would establish the AU Mic system as a compact resonant multiplanet chain in a 4:6:9 period commensurability. These results demonstrate that the AU Mic planetary system is dynamically interacting, producing detectable TTVs, and the implied orbital dynamics may inform the formation mechanisms for this young system. We recommend future RV and TTV observations of AU Mic b and c to further constrain the masses and confirm the existence of possible additional planet(s).

Keywords: Exoplanet astronomy, Exoplanets
Nova Sagittarii 1943 (V1148 Sgr): A Luminous Red Nova?. Nova Sagittarii 1943 (V1148 Sgr) was an eighth magnitude optical transient that was unusual in having a late-type spectrum during its outburst, in striking contrast to the normal high-excitation spectra seen in classical novae. Unfortunately, only an approximate position was given in the discovery announcement, hampering follow-up attempts to observe its remnant. We have identified the nova on two photographic plates in the Harvard archive, allowing us to determine a precise astrometric position. Apart from these two plates, obtained in 1943 and 1944, none of the photographs in the Harvard collection, from 1897 to 1950, show V1148 Sgr to limits as faint as g ≃ 18.3. Modern deep images show a candidate remnant at i ≃ 19.2, lying only 0.″26 from the site of the nova. V1148 Sgr may have been a luminous red nova (LRN), only the sixth one known in the Milky Way. However, it lacks the near- and mid-infrared excesses, and millimeter-wave emission, seen in other LRNe, leaving its nature uncertain. We urge spectroscopy of the candidate remnant.

Keywords: Variable stars, Transient sources, Stellar mergers, Novae
Improved Orbital Constraints and Hα Photometric Monitoring of the Directly Imaged Protoplanet Analog HD 142527 B. Companions embedded in the cavities of transitional circumstellar disks have been observed to exhibit excess luminosity at Hα, an indication that they are actively accreting. We report 5 yr (2013-2018) of monitoring of the position and Hα excess luminosity of the embedded, accreting low-mass stellar companion HD 142527 B from the MagAO/VisAO instrument. We use pyklip, a Python implementation of the Karhunen-Loeve Image Processing algorithm, to detect the companion. Using pyklip forward modeling, we constrain the relative astrometry to 1-2 mas precision and achieve sufficient photometric precision (±0.2 mag, 3% error) to detect changes in the Hα contrast of the companion over time. In order to accurately determine the relative astrometry of the companion, we conduct an astrometric calibration of the MagAO/VisAO camera against 20 yr of Keck/NIRC2 images of the Trapezium cluster. We demonstrate agreement of our VisAO astrometry with other published positions for HD 142527 B, and use orbitize! to generate a posterior distribution of orbits fit to the relative astrometry of HD 142527 B. Our data suggest that the companion is close to periastron passage, on an orbit significantly misaligned with respect to both the wide circumbinary disk and the recently observed inner disk encircling HD 142527 A. We translate observed Hα contrasts for HD 142527 B into mass accretion rate estimates on the order of 4-9 × 10-10 M ☉ yr-1. Photometric variation in the Hα excess of the companion suggests that the accretion rate onto the companion is variable. This work represents a significant step toward observing accretion-driven variability onto protoplanets, such as PDS 70 b&amp;c.

Keywords: Accretion, Direct imaging, Star formation, Stellar accretion, Orbit determination
The Hubble PanCET Program: A Featureless Transmission Spectrum for WASP-29b and Evidence of Enhanced Atmospheric Metallicity on WASP-80b. We present a uniform analysis of transit observations from the Hubble Space Telescope and Spitzer Space Telescope of two warm gas giants orbiting K-type stars-WASP-29b and WASP-80b. The transmission spectra, which span 0.4-5.0 μm, are interpreted using a suite of chemical equilibrium PLATON atmospheric retrievals. Both planets show evidence of significant aerosol opacity along the day-night terminator. The spectrum of WASP-29b is flat throughout the visible and near-infrared, suggesting the presence of condensate clouds extending to low pressures. The lack of spectral features hinders our ability to constrain the atmospheric metallicity and C/O ratio. In contrast, WASP-80b shows a discernible, albeit muted H2O absorption feature at 1.4 μm, as well as a steep optical spectral slope that is caused by fine-particle aerosols and/or contamination from unocculted spots on the variable host star. WASP-80b joins the small number of gas-giant exoplanets that show evidence for enhanced atmospheric metallicity: the transmission spectrum is consistent with metallicities ranging from ~30-100 times solar in the case of cloudy limbs to a few hundred times solar in the cloud-free scenario. In addition to the detection of water, we infer the presence of CO2 in the atmosphere of WASP-80b based on the enhanced transit depth in the Spitzer 4.5 μm bandpass. From a complementary analysis of Spitzer secondary eclipses, we find that the dayside emission from WASP-29b and WASP-80b is consistent with brightness temperatures of 937 ± 48 and 851 ± 14 K, respectively, indicating relatively weak day-night heat transport and low Bond albedo.

Keywords: Exoplanet atmospheric composition , Exoplanet atmospheres, Transmission spectroscopy
Optical Linear Polarization Study toward Czernik 3 Open Cluster at Different Spatial Scales. We present the optical linear polarization observation of stars toward the core of the Czernik 3 cluster in the Sloan i band. The data were obtained using the EMPOL instrument on the 1.2 m telescope at Mount Abu Observatory. We study the dust distribution toward this cluster by combining the results from our polarization observations with the data from Gaia EDR3, WISE, and the H I, 12CO surveys. In addition, we use the polarimetric data of previously studied clusters within 15° of Czernik 3 to understand the large-scale dust distribution. The observational results of Czernik 3 show a large range in the degree of polarization, indicating that the dust is not uniformly distributed over the plane of the sky, even on a small scale. The distance to Czernik 3 is constrained to 3.6 ± 0.8 kpc using the member stars in the core region identified from Gaia EDR3 astrometry. This makes it one of the most distant clusters observed for optical polarization so far. The variation of observed degree of polarization and extinction toward this cluster direction suggests the presence of at least two dust layers along this line of sight at distances of ~1 and ~3.4 kpc. There is an indication of the presence of dust in the center of the cluster as seen from an increase in the degree of polarization and WISE W4 flux. The large-scale distribution of dust reveals the presence of a region of low dust content between the Local Arm and the Perseus arm.

Keywords: Interstellar dust extinction, Milky Way disk, Starlight polarization, Interstellar medium, Open star clusters
New Photometric Calibration of the Wide Field Camera 3 Detectors. We present a new photometric calibration of the WFC3-UVIS and WFC3-IR detectors based on observations collected from 2009 to 2020 for four white dwarfs-namely, GRW +70 5824, GD 153 , GD 71 , G191B2B-and a G-type star, P330E. These calibrations include recent updates to the Hubble Space Telescope primary standard white dwarf models and a new reference flux for Vega. Time-dependent inverse sensitivities for the two WFC3-UVIS chips, UVIS1 and UVIS2, were calculated for all 42 full-frame filters after accounting for temporal changes in the observed count rates with respect to a reference epoch in 2009. We also derived new encircled energy values for a few filters and improved sensitivity ratios for the two WFC3-UVIS chips by correcting for sensitivity changes with time. Updated inverse sensitivity values for the 20 WFC3-UVIS quad filters and 15 WFC3-IR filters were derived by using the new models for the primary standards, the new Vega reference flux, and, in the case of the IR detector, new flat fields. However, these values do not account for any sensitivity changes with time. The new calibration provides a photometric internal precision better than 0.5% for the wide-, medium-, and narrowband WFC3-UVIS filters; 5% for the quad filters; and 1% for the WFC3-IR filters. As of 2020 October 15, an updated set of photometric keywords were populated in the WFC3 image headers.

Keywords: CCD photometry, Photometric systems, Hubble Space Telescope, HST photometry, Flux calibration, Astronomical instrumentation, Spectrophotometric standards
The POKEMON Speckle Survey of Nearby M Dwarfs. I. New Discoveries. M dwarfs are favorable targets for exoplanet detection with current instrumentation, but stellar companions can induce false positives and inhibit planet characterization. Knowledge of stellar companions is also critical to our understanding of how binary stars form and evolve. We have therefore conducted a survey of stellar companions around nearby M dwarfs, and here we present our new discoveries. Using the Differential Speckle Survey Instrument at the 4.3 m Lowell Discovery Telescope, and the similar NN-EXPLORE Exoplanet Stellar Speckle Imager at the 3.5 m WIYN telescope, we carried out a volume-limited survey of M-dwarf multiplicity to 15 parsecs, with a special emphasis on including the later M dwarfs that were overlooked in previous surveys. Additional brighter targets at larger distances were included for a total sample size of 1070 M dwarfs. Observations of these 1070 targets revealed 26 new companions; 22 of these systems were previously thought to be single. If all new discoveries are confirmed, then the number of known multiples in the sample will increase by 7.6%. Using our observed properties, as well as the parallaxes and 2MASS K magnitudes for these objects, we calculate the projected separation, and estimate the mass ratio and component spectral types, for these systems. We report the discovery of a new M-dwarf companion to the white dwarf Wolf 672 A, which hosts a known M-dwarf companion as well, making the system trinary. We also examine the possibility that the new companion to 2MASS J13092185-2330350 is a brown dwarf. Finally, we discuss initial insights from the POKEMON survey.

Keywords: M dwarf stars, Binary stars, Close binary stars, White dwarf stars, Low mass stars, Speckle interferometry, Visual binary stars, High angular resolution
The Interferometric Binary ϵ Cnc in Praesepe: Precise Masses and Age. We observe the brightest member of the Praesepe cluster, ϵ Cnc, to precisely measure the characteristics of the stars in this binary system, en route to a new measurement of the cluster's age. We present spectroscopic radial velocity measurements and interferometric observations of the sky-projected orbit to derive the masses, which we find to be M 1/M ⊙ = 2.420 ± 0.008 and M 2/M ⊙ = 2.226 ± 0.004. We place limits on the color-magnitude positions of the stars by using spectroscopic and interferometric luminosity ratios while trying to reproduce the spectral energy distribution of ϵ Cnc. We reexamine the cluster membership of stars at the bright end of the color-magnitude diagram using Gaia data and literature radial velocity information. The binary star data are consistent with an age of 637 ± 19 Myr, as determined from MIST model isochrones. The masses and luminosities of the stars appear to select models with the most commonly used amount of convective core overshooting.

Keywords: White dwarf stars, Spectroscopic binary stars, Long baseline interferometry, Open star clusters, Stellar evolution
SPORK That Spectrum: Increasing Detection Significances from High-resolution Exoplanet Spectroscopy with Novel Smoothing Algorithms. Spectroscopic studies of planets outside of our own solar system provide some of the most crucial information about their formation, evolution, and atmospheric properties. In ground-based spectroscopy, the process of extracting the planets signal from the stellar and telluric signal has proven to be the most difficult barrier to accurate atmospheric information. However, with novel normalization and smoothing methods, this barrier can be minimized and the detection significance dramatically increased over existing methods. In this paper, we take two examples of CRIRES emission spectroscopy taken of HD 209458 b and HD 179949 b, and apply SPORK (SPectral cOntinuum Refinement for telluriKs) and iterative smoothing to boost the detection significance from 5.78 to 9.71σ, and from 4.38σ to 6.89σ, respectively. These methods, which largely address systematic quirks introduced by imperfect detectors or reduction pipelines, can be employed in a wide variety of scenarios, from archival data sets to simulations of future spectrographs.

Keywords: High resolution spectroscopy, Exoplanet atmospheres, Hot Jupiters
USNO Bright Star Catalog, Version 1. The USNO Bright Star Catalog (UBSC) is a new astrometric catalog of the 1423 brightest stars covering the entire sky, which is published online. It is nearly complete to V = 3 mag except for three stellar systems. A combined astrometric solution of the Hipparcos Intermediate Astrometry Data and two dedicated ground-based campaigns in 2013-2020 is the basis for this catalog. The astrometric parameters for each star include position coordinates, parallax, and proper motion components, and their covariances on the Hipparcos mean epoch 1991.25. 64% of the catalog are flagged as known or suspected double or binary stars. UBSC lists 68 stars missing in Gaia EDR3 and another 114 stars without Gaia parallaxes or proper motions. The formal precision achieved for proper motions is comparable to that of Gaia.

Keywords: Trigonometric parallax, Astrometric binary stars, Astrometry, Proper motions, Catalogs
Precise Positions of Five Major Uranian Satellites During 2008-2014 Based on Gaia EDR3. The five major Uranian satellites (Ariel, Umbriel, Titania, Oberon, and Miranda) were observed by a 1.56 m telescope at Sheshan Station of Shanghai Astronomical Observatory during 2008-2014 and a total of 1915 positions of these five satellites were presented in this paper. Since all five satellites are close to Uranus, their positions are affected by the uneven background, which is caused by the halo of Uranus. The median filtering method is used to remove the influence of the halo of the bright Uranus, which also made the rate of target detection increase by 30%-100%, especially for Miranda. Gaia EDR3 is used as the reference catalog when calculating positions of the five satellites. A comparison between our positions with the theoretical positions of the satellites from IMCCE is given. Such precise positions over a long time will be very helpful to improve the orbit parameters of the five major Uranian satellites. * Released on 2021 March 1st.

Keywords: Uranian satellites
Cupid is not Doomed Yet: On the Stability of the Inner Moons of Uranus. Some of the small inner moons of Uranus have very closely-spaced orbits. Multiple numerical studies have found that the moons Cressida and Desdemona, within the Portia subgroup, are likely to collide in less than 100 Myr. The subsequent discovery of three new moons (Cupid, Perdita, and Mab) made the system even more crowded. In particular, it has been suggested that the Belinda group (Cupid, Belinda, and Perdita) will become unstable in as little as 105 yr. Here we revisit the issue of the stability of the inner moons of Uranus using updated orbital elements and considering tidal dissipation. We find that the Belinda group can be stable on 108 yr timescales due to an orbital resonance between Belinda and Perdita. We find that tidal evolution cannot form the Belinda-Perdita resonance, but convergent migration could contribute to the long-term instability of the Portia group. We propose that Belinda captured Perdita into the resonance during the last episode of disruption and reaccretion among the inner moons, possibly hundreds of Myr ago.

Keywords: Uranian satellites
The Airborne Infrared Spectrometer: Development, Characterization, and the 2017 August 21 Eclipse Observation. On 2017 August 21, the Airborne Infrared Spectrometer (AIR-Spec) observed the total solar eclipse at an altitude of 14 km from aboard the NSF/NCAR Gulfstream V research aircraft. The instrument successfully observed the five coronal emission lines that it was designed to measure: Si X 1.431 μm, S XI 1.921 μm, Fe IX 2.853 μm, Mg VIII 3.028 μm, and Si IX 3.935 μm. Characterizing these magnetically sensitive emission lines is an important first step in designing future instruments to monitor the coronal magnetic field, which drives space weather events, as well as coronal heating, structure, and dynamics. The AIR-Spec instrument includes an image stabilization system, feed telescope, grating spectrometer, and slit-jaw imager. This paper details the instrument design, optical alignment method, image processing, and data calibration approach. The eclipse observations are described and the available data are summarized.

Keywords: Total eclipses, Solar E corona, Solar coronal lines, Spectrometers, Solar instruments
Searching for Variable Stars in the Open Cluster NGC 2355 and Its Surrounding Region. We have investigated the variable stars in the field surrounding NGC 2355 based on the time-series photometric observation data. More than 3000 CCD frames were obtained in the V band spread over 13 nights with the Nanshan One-meter Wide-field Telescope. We have detected 88 variable stars, containing 72 new variable stars and 16 known variable stars. By analyzing these light curves, we classified the variable stars as follows: 26 eclipsing binaries, 52 pulsating stars, four rotating variables, and six unclear type-variable stars for which their periods are much longer than the time baseline chosen. Employing Gaia DR2 parallax, kinematics, and photometry, the cluster memberships of these variable stars were also analyzed for NGC 2355. In addition to the 11 variable members reported by Cantat-Gaudin et al. (2018), we identify four more variable member candidates located at the outer region of NGC 2355 and showed homogeneity in space positions and kinematic properties with the cluster members. The main physical parameters of NGC 2355 estimated from the two-color and color-magnitude diagrams are log(age/yr) = 8.9, E(B - V) = 0.24 mag, and [Fe/H] = -0.07 dex.

Keywords: Open star clusters, Astronomy data analysis, Variable stars
Influence of the Gaia-Sausage-Enceladus on the Density Shape of the Galactic Stellar Halo Revealed by Halo K Giants from the LAMOST Survey. We present a study of the influence of the Gaia-Sausage-Enceladus (GSE) on the density shape of the Galactic stellar halo using 11,624 K giants from the LAMOST survey. Every star is assigned a probability of being a member of the GSE based on its spherical velocities and metallicity by a Gaussian mixture model. We divide the stellar halo into two parts by the obtained probabilities, of which one is composed of the GSE members and defined as the GSE-related halo, and the other one is referred to as the GSE-removed halo. Using a nonparametric method, the radial number density profiles of the two stellar halos can be well described by a single power law with a variable flattening q ( $r=\sqrt{{R}^{2}+{\left[(Z/q(r))\right]}^{2}},\nu ={\nu }_{0}{r}^{-\alpha }$ r=R2+(Z/q(r))2,ν=ν0r-α ). The index α is 4.92 ± 0.12 for the GSE-related halo and 4.25 ± 0.14 for the GSE-removed halo. Both of the stellar halos are vertically flattened at smaller radii but become more spherical at larger radii. We find that the GSE-related halo is less vertically flattened than the GSE-removed halo, and the difference of q between the two stellar halos ranges from 0.07 to 0.15. However, after the consideration of the bias, it is thought to be within 0.08 at most of the radii. Finally, we compare our results with two Milky Way analogs that experience a significant major merger in the TNG50 simulation. The study of the two analogs also shows that the major merger-related stellar halo has a smaller ellipticity than the major merger-removed stellar halo.

Keywords: Milky Way Galaxy physics, Milky Way stellar halo, Milky Way formation, Galaxy mergers