Sazuna/UAT_keywords huggingface dataset:
Multiwavelength Photometry Derived from Monochromatic Kepler Data. The Kepler mission has provided a wealth of data, revealing new insights in time-domain astronomy. However, Kepler's single bandpass has limited studies to a single wavelength. In this work we build a data-driven, pixel-level model for the pixel response function (PRF) of Kepler targets, modeling the image data from the spacecraft. Our model is sufficiently flexible to capture known detector effects, such as nonlinearity, intrapixel sensitivity variations, and focus change. In theory, the shape of the Kepler PRF should also be weakly wavelength-dependent, due to optical chromatic aberration and a wavelength-dependent detector response functions. We are able to identify these predicted changes in shape of the PRF using the residuals between Kepler data and our model. In this work, we show that these PRF changes correspond to wavelength variability in Kepler targets using a small sample of eclipsing binaries. Using our model, we demonstrate that pixel-level light curves of eclipsing binaries show variable eclipse depths, ellipsoidal modulation, and limb darkening. These changes at the pixel level are consistent with multiwavelength photometry. Our work suggests that each pixel in the Kepler data of a single target has a different effective wavelength, ranging from ≈550 to 750 nm. In this proof of concept, we demonstrate our model, and discuss possible uses for the wavelength-dependent PRF of Kepler. These uses include characterizing variable systems, and vetting exoplanet discoveries at the pixel level. The chromatic PRF of Kepler is due to weak wavelength dependence in the optical systems and detector of the telescope, and similar chromatic PRFs are expected in other similar telescopes, notably the NASA TESS telescope.

Keywords: Multi-color photometry, Time series analysis, Astronomical instrumentation
Protoplanetary Disk Rings as Sites for Planetesimal Formation. Axisymmetric dust rings are a ubiquitous feature of young protoplanetary disks. These rings are likely caused by pressure bumps in the gas profile; a small bump can induce a traffic-jam-like pattern in the dust density, while a large bump may halt radial dust drift entirely. The resulting increase in dust concentration may trigger planetesimal formation by the streaming instability (SI), as the SI itself requires some initial concentration of dust. Here we present the first 3D simulations of planetesimal formation in the presence of a pressure bump modeled specifically after those seen by Atacama Large Millimeter/submillimeter Array. We place a pressure bump at the center of a large 3D shearing box, along with an initial solid-to-gas ratio of Z = 0.01, and we include both particle back-reaction and particle self-gravity. We consider millimeter-sized and centimeter-sized particles separately. For simulations with centimeter-sized particles, we find that even a small pressure bump leads to the formation of planetesimals via the SI; a pressure bump does not need to fully halt radial particle drift for the SI to become efficient. Furthermore, pure gravitational collapse via concentration in pressure bumps (such as would occur at sufficiently high concentrations and without the SI) is not responsible for planetesimal formation. For millimeter-sized particles, we find tentative evidence that planetesimal formation does not occur. If this result is confirmed at higher resolution, it could put strong constraints on where planetesimals can form. Ultimately, our results show that for centimeter-sized particles planetesimal formation in pressure bumps is extremely robust.

Keywords: Planetary system formation, Protoplanetary disks, Planet formation, Planetesimals
TOI-811b and TOI-852b: New Transiting Brown Dwarfs with Similar Masses and Very Different Radii and Ages from the TESS Mission. We report the discovery of two transiting brown dwarfs (BDs), TOI-811b and TOI-852b, from NASA's Transiting Exoplanet Survey Satellite mission. These two transiting BDs have similar masses but very different radii and ages. Their host stars have similar masses, effective temperatures, and metallicities. The younger and larger transiting BD is TOI-811b at a mass of Mb = 59.9 ± 13.0MJ and radius of Rb = 1.26 ± 0.06RJ, and it orbits its host star in a period of P = 25.16551 ± 0.00004 days. We derive the host star's age of ${93}_{-29}^{+61}$ Myr from an application of gyrochronology. The youth of this system, rather than external heating from its host star, is why this BD's radius is relatively large. This constraint on the youth of TOI-811b allows us to test substellar mass-radius evolutionary models at young ages where the radius of BDs changes rapidly. TOI-852b has a similar mass at Mb = 53.7 ± 1.4MJ but is much older (4 or 8 Gyr, based on bimodal isochrone results of the host star) and is also smaller with a radius of Rb = 0.83 ± 0.04RJ. TOI-852b's orbital period is P = 4.94561 ± 0.00008 days. TOI-852b joins the likes of other old transiting BDs that trace out the oldest substellar mass-radius evolutionary models where contraction of the BD's radius slows and approaches a constant value. Both host stars have a mass of M⋆ = 1.32M⊙ ± 0.05 and differ in their radii, Teff, and [Fe/H], with TOI-811 having R⋆ = 1.27 ± 0.09R⊙, Teff = 6107 ± 77 K, and [Fe/H] = + 0.40 ± 0.09 and TOI-852 having R⋆ = 1.71 ± 0.04R⊙, Teff = 5768 ± 84 K, and [Fe/H] = + 0.33 ± 0.09. We take this opportunity to examine how TOI-811b and TOI-852b serve as test points for young and old substellar isochrones, respectively.

Keywords: Brown dwarfs, Substellar companion stars, Photometry, Spectroscopy, Radial velocity, Transit photometry
The Mass-loss History of the Red Hypergiant VY CMa. Imaging and spectroscopy of the knots, clumps, and extended arcs in the complex ejecta of VY CMa confirm a record of high mass-loss events over the past few hundred years. Hubble Space Telescope/Space Telescope Imaging Spectrograph spectroscopy of numerous small knots close to the star allow us to measure their radial velocities from the strong K emission and determine their separate motions, spatial orientations, and time since ejecta. Their ages concentrate around 70, 120, 200, and 250 yr ago. A K emission knot only 50 mas from the star ejected as recently as 1985-1995 may coincide with an H2O maser. Comparison with VY CMa's historic light curve from 1800 to the present shows several knots with ejection times that correspond with extended periods of variability and deep minima. The similarity of this correspondence in VY CMa with the remarkable recent dimming of Betelgeuse and an outflow of gas is apparent. The evidence for similar outflows from the surface of a more typical red supergiant suggests that discrete ejections are more common and surface or convective activity is a major source of mass loss for red supergiants. * Based on observations made with the NASA/ESA Hubble Space Telescope which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Keywords: Circumstellar matter, Massive stars, Red supergiant stars, Stellar mass loss
Space Weathering within C-complex Main Belt Asteroid Families. Using data from the Sloan Digital Sky Survey Moving Object Catalog, we study color as a function of size for C-complex families in the main asteroid belt to improve our understanding of space weathering of carbonaceous materials. We find two distinct spectral slope trends: Hygiea type and Themis type. The Hygiea-type families exhibit a reduction in spectral slope with increasing object size until a minimum slope value is reached and the trend reverses with increasing slope with increasing object size. The Themis family shows an increase in spectral slope with increasing object size until a maximum slope is reached and the spectral slope begins to decrease slightly or plateaus for the largest objects. Most families studied show the Hygiea-type trend. The processes responsible for these distinct changes in spectral slope affect several different taxonomic classes within the C-complex and appear to act quickly to alter the spectral slopes of the family members.

Keywords: Main belt asteroids, Asteroids, Hirayama families, Solar system astronomy
An Intermediate-age Alpha-rich Galactic Population in K2. We explore the relationships between the chemistry, ages, and locations of stars in the Galaxy using asteroseismic data from the K2 mission and spectroscopic data from the Apache Point Galactic Evolution Experiment survey. Previous studies have used giant stars in the Kepler field to map the relationship between the chemical composition and the ages of stars at the solar circle. Consistent with prior work, we find that stars with high [α/Fe] have distinct, older ages in comparison to stars with low [α/Fe]. We provide age estimates for red giant branch (RGB) stars in the Kepler field, which support and build upon previous age estimates by taking into account the effect of α-enrichment on opacity. Including this effect for [α/Fe]-rich stars results in up to 10% older ages for low-mass stars relative to corrected solar mixture calculations. This is a significant effect that Galactic archeology studies should take into account. Looking beyond the Kepler field, we estimate ages for 735 RGB stars from the K2 mission, mapping age trends as a function of the line of sight. We find that the age distributions for low- and high-[α/Fe] stars converge with increasing distance from the Galactic plane, in agreement with suggestions from earlier work. We find that K2 stars with high [α/Fe] appear to be younger than their counterparts in the Kepler field, overlapping more significantly with a similarly aged low-[α/Fe] population. This observation may suggest that star formation or radial migration proceeds unevenly in the Galaxy.

Keywords: Galaxy formation, Stellar ages, Milky Way formation, Surveys, Stellar abundances, Galaxy stellar content, Galaxy evolution, Red giant stars, Asteroseismology
A Comprehensive Analysis of NGC 2158 in the Gaia Era: Photometric Parameters, Apex, and Orbit. We present an investigation of NGC 2158 using Gaia DR2 data. We identified 800 most likely cluster members with membership probability higher than 90%. The mean proper motions of this object are determined as (μx = -0.203 ± 0.003, μy = -1.99 ± 0.004) mas yr-1. The limiting radius, log(age), and distance of the cluster are obtained as 23.5 arcmin, 9.38 ± 0.04 Gyr, and 4.69 ± 0.22 kpc, respectively. The overall mass function slope (0.93 ± 0.14) is flatter than the Salpeter value (1.35) within the mass range of 1.17-1.44 M⊙. This cluster also shows the mass-segregation effect and our study demonstrates that NGC 2158 is a dynamically relaxed open cluster. Using the apex diagram (AD), the apex coordinates of the cluster are obtained in different ways and are examined using the (μU,μT) diagram. The best value of the apex coordinates is determined as A = 87°24 ± 1°60, D = -36°61 ± 5°30. We also determined the orbit of the cluster and found that NGC 2158 moves almost in the solar antapex direction. The resulting spatial velocity of NGC 2158 is 51 km s-1. A significant oscillation along the Z-coordinate up to 529 pc is detected. Various scenarios regarding the origin of this cluster are also discussed.

Keywords: Stellar kinematics, Open star clusters, Apex, Astrometry, S stars, Hertzsprung Russell diagram, Orbit determination
Astrometric and Photometric Investigation of Three Old Age Open Clusters in the Gaia Era: Berkeley 32, Berkeley 98, and King 23. Using the photometric and kinematical data from Gaia Data Release 2, three old open clusters namely Berkeley 32 (Be 32), Berkeley 98 (Be 98), and King 23 are investigated. The latter two of these clusters are poorly studied in the literature. The numbers of the most probable cluster members are 563, 260, and 114 for Be 32, Be 98, and King 23, respectively, with membership probabilities higher than 80% and lying within the clusters' limiting radii. Mean proper motions (PMs; ${\mu }_{\alpha }\cos \delta $ and μδ) of the clusters are determined as (-0.34 ± 0.008, -1.60 ± 0.006), (-1.34 ± 0.007, -3.22 ± 0.008), and (-0.46 ± 0.009, -0.87 ± 0.012) mas yr-1. The errors mentioned in the PMs are the Gaussian fitting errors. The blue straggler stars (BSS) in all three old clusters were found to exhibit centralized radial distribution. The clusters' radii are determined as 9'4, 12'95, and 6'6 for Be 32, Be 98, and King 23 using radial density profiles. Ages of the clusters determined by isochrone fitting are 4.90 ± 0.22, 3.23 ± 0.15, and 1.95 ± 0.22 Gyr. The errors given in the clusters' ages are the internal errors. The mass function slopes are found to be flatter than Salpeter's value for all three clusters. All three clusters are found to be dynamically relaxed. Galactic orbits are derived for these clusters, which demonstrate that the studied clusters follow a circular path around the Galactic center.

Keywords: Initial mass function, Open star clusters, Hertzsprung Russell diagram, Orbit determination, Star clusters
Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey. I. Confirmation of an Eccentric, Cool Jupiter with an Interior Earth-sized Planet Orbiting Kepler-1514. Despite the severe bias of the transit method of exoplanet discovery toward short orbital periods, a modest sample of transiting exoplanets with orbital periods greater than 100 days is known. Long-term radial velocity (RV) surveys are pivotal to confirming these signals and generating a set of planetary masses and densities for planets receiving moderate to low irradiation from their host stars. Here we conduct RV observations of Kepler-1514 from the Keck I telescope using the High Resolution Echelle Spectrometer. From these data, we measure the mass of the statistically validated giant (1.108 ± 0.023 RJ) exoplanet Kepler-1514 b with a 218-day orbital period as 5.28 ± 0.22 MJ. The bulk density of this cool (∼390 K) giant planet is ${4.82}_{-0.25}^{+0.26}$ g cm-3, consistent with a core supported by electron degeneracy pressure. We also infer an orbital eccentricity of ${0.401}_{-0.014}^{+0.013}$ from the RV and transit observations, which is consistent with planet-planet scattering and disk cavity migration models. The Kepler-1514 system contains an Earth-size, Kepler Object of Interest on a 10.5-day orbit that we statistically validate against false-positive scenarios, including those involving a neighboring star. The combination of the brightness (V = 11.8) of the host star and the long period, low irradiation, and high density of Kepler-1514 b places this system among a rare group of known exoplanetary systems and as one that is amenable to continued study. * Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Keywords: Exoplanets, Direct imaging, Radial velocity, Transit photometry, Extrasolar gaseous giant planets
Contrast and Temperature Dependence of Multi-epoch High-resolution Cross-correlation Exoplanet Spectroscopy. While high-resolution cross-correlation spectroscopy (HRCCS) techniques have proven effective at characterizing the atmospheres of transiting and nontransiting hot Jupiters, the limitations of these techniques are not well understood. We present a series of simulations of one HRCCS technique, which combines the cross-correlation functions from multiple epochs, to place temperature and contrast limits on the accessible exoplanet population for the first time. We find that planets approximately Saturn-sized and larger within ∼0.2 au of a Sun-like star are likely to be detectable with current instrumentation in the L band, a significant expansion compared with the previously studied population. Cooler (Teq ≤ 1000 K) exoplanets are more detectable than suggested by their photometric contrast alone as a result of chemical changes that increase spectroscopic contrast. The L-band CH4 spectrum of cooler exoplanets enables robust constraints on the atmospheric C/O ratio at Teq ∼ 900 K, which have proven difficult to obtain for hot Jupiters. These results suggest that the multi-epoch approach to HRCCS can detect and characterize exoplanet atmospheres throughout the inner regions of Sun-like systems with existing high-resolution spectrographs. We find that many epochs of modest signal-to-noise ratio (S/Nepoch ∼ 1500) yield the clearest detections and constraints on C/O, emphasizing the need for high-precision near-infrared telluric correction with short integration times.

Keywords: Exoplanet detection methods, Hot Jupiters, Exoplanet atmospheres
The JPL Planetary and Lunar Ephemerides DE440 and DE441. The planetary and lunar ephemerides called DE440 and DE441 have been generated by fitting numerically integrated orbits to ground-based and space-based observations. Compared to the previous general-purpose ephemerides DE430, seven years of new data have been added to compute DE440 and DE441, with improved dynamical models and data calibration. The orbit of Jupiter has improved substantially by fitting to the Juno radio range and Very Long Baseline Array (VLBA) data of the Juno spacecraft. The orbit of Saturn has been improved by radio range and VLBA data of the Cassini spacecraft, with improved estimation of the spacecraft orbit. The orbit of Pluto has been improved from use of stellar occultation data reduced against the Gaia star catalog. The ephemerides DE440 and DE441 are fit to the same data set, but DE441 assumes no damping between the lunar liquid core and the solid mantle, which avoids a divergence when integrated backward in time. Therefore, DE441 is less accurate than DE440 for the current century, but covers a much longer duration of years -13,200 to +17,191, compared to DE440 covering years 1550-2650.

Keywords: Orbital motion, Solar system planets, Orbits, The Sun, Solar system, The Moon, Celestial mechanics, Pluto, Earth-moon system, Solar system astronomy
The McDonald Accelerating Stars Survey (MASS): White Dwarf Companions Accelerating the Sun-like Stars 12 Psc and HD 159062. We present the discovery of a white dwarf companion to the G1 V star 12 Psc found as part of a Keck adaptive optics imaging survey of long-term accelerating stars from the McDonald Observatory Planet Search Program. Twenty years of precise radial-velocity monitoring of 12 Psc with the Tull Spectrograph at the Harlan J. Smith telescope reveals a moderate radial acceleration (≈10 m s-1 yr -1), which together with relative astrometry from Keck/NIRC2 and the astrometric acceleration between Hipparcos and Gaia DR2 yields a dynamical mass of MB = ${0.605}_{-0.022}^{+0.021}$ M⊙ for 12 Psc B, a semimajor axis of ${40}_{-4}^{+2}$ au, and an eccentricity of 0.84 ± 0.08. We also report an updated orbital fit of the white dwarf companion to the metal-poor (but barium-rich) G9 V dwarf HD 159062 based on new radial-velocity observations from the High-Resolution Spectrograph at the Hobby-Eberly Telescope and astrometry from Keck/NIRC2. A joint fit of the available relative astrometry, radial velocities, and tangential astrometric acceleration yields a dynamical mass of MB = ${0.609}_{-0.011}^{+0.010}$ M⊙ for HD 159062 B, a semimajor axis of ${60}_{-7}^{+5}$ au, and preference for circular orbits (e &lt; 0.42 at 95% confidence). 12 Psc B and HD 159062 B join a small list of resolved Sirius-like benchmark white dwarfs with precise dynamical mass measurements which serve as valuable tests of white dwarf mass-radius cooling models and probes of AGB wind accretion onto their main-sequence companions.

Keywords: Binary stars, White dwarf stars, Astrometric binary stars, Direct imaging, Radial velocity, Orbit determination
The ANTARES Astronomical Time-domain Event Broker. We describe the Arizona-NOIRLab Temporal Analysis and Response to Events System (ANTARES), a software instrument designed to process large-scale streams of astronomical time-domain alerts. With the advent of large-format CCDs on wide-field imaging telescopes, time-domain surveys now routinely discover tens of thousands of new events each night, more than can be evaluated by astronomers alone. The ANTARES event broker will process alerts, annotating them with catalog associations and filtering them to distinguish customizable subsets of events. We describe the data model of the system, the overall architecture, annotation, implementation of filters, system outputs, provenance tracking, system performance, and the user interface.

Keywords: Astronomical methods, Computational methods, Time domain astronomy, Astronomy software
Are There Transit Timing Variations for the Exoplanet Qatar-1b?. Motivated by the unsettled conclusion on whether there are any transit timing variations (TTVs) for the exoplanet Qatar-1b, 10 new transit light curves are presented and a TTV analysis with a baseline of 1400 epochs is performed. Because the linear model provides a good fit with a reduced chi-square of ${\chi }_{\mathrm{red}}^{2}=2.59$ and the false-alarm probabilities of the possible TTV frequencies are as large as 35%, our results are consistent with a null-TTV model. Nevertheless, a new ephemeris with a reference time of T0 = 2455647.63360 ± 0.00008 (BJD) and a period of P = 1.4200236 ± 0.0000001 (day) is obtained. In addition, the updated orbital semimajor axis and planetary radius in units of stellar radius are provided, and the lower limit of the modified stellar tidal quality factor is also determined.

Keywords: Exoplanet astronomy, Transit photometry
DRAGraces: A Pipeline for the GRACES High-resolution Spectrograph at Gemini. This paper describes the software Data Reduction and Analysis for GRACES (DRAGRACES), which is a pipeline reducing spectra from Gemini Remote Access to the CFHT ESPaDOnS Spectrograph (GRACES) at the Gemini North Telescope. The code is written in the IDL language. It is designed to find all the GRACES frames in a given directory, automatically determine the list of bias, flat, arc, and science frames, and perform the whole reduction and extraction within a few minutes. We compare the output from DRAGRACES with that of the Open source Pipeline for ESPaDOnS Reduction and Analysis (OPERA), a pipeline developed at the Canada-France-Hawaii Telescope (CFHT) that also can extract GRACES spectra. Both pipelines were developed completely independently, yet they give very similar extracted spectra. They both have their advantages and disadvantages. For instance, DRAGRACES is more straightforward and easy to use and is less likely to be derailed by a parameter that needs to be tweaked, while OPERA offers a more careful extraction that can be significantly superior when the highest resolution is required and when the signal-to-noise ratio is low. One should compare both before deciding which one to use for their science. Yet, both pipelines deliver a fairly comparable resolution power (R ∼ 52.8k and 36.6k for DRAGRACES and R ∼ 58k and 40k for OPERA in high- and low-resolution spectral modes, respectively), wavelength solution, and signal-to-noise ratio per resolution element. * First released on 2016 September 20.

Keywords: Software documentation, High resolution spectroscopy, Astronomy data reduction