Sazuna/UAT_keywords huggingface dataset:
A Spatially-resolved Large Cavity of the J0337 Protoplanetary Disk in Perseus. We present Keck/NIRC2 K p L p high-contrast imaging observations of a J0337 protoplanetary disk. The data discover the spatially-resolved large cavity, which is the second report among protoplanetary disks in the Perseus star-forming region after the LkHα 330 system. Our data and forward modeling using RADMC-3D suggests ~80 au for the cavity radius. There is discrepancy between J0337's spectral energy distribution (SED) and the modeled SED at ~10 μm and this suggests an unseen inner disk. We also searched for companions around J0337 but did not detect any companion candidates at separations between 0.″1 and 2.″5. The L p-band detection limit corresponds to ~20M Jup at 60 au, ~9-10M Jup at 90 au, and ~3M Jup at &gt;120 au. Compared with other young systems with large cavities such as PDS 70 and RX J1604, multiple Jovian planets, a single eccentric Jovian planet, or a massive brown dwarf at an inner separation could exist within the cavity.

Keywords: Protoplanetary disks, Planet formation
Multiwavelength Mitigation of Stellar Activity in Astrometric Planet Detection. Astrometry has long been a promising technique for exoplanet detection. At the theoretical limits, astrometry would allow for the detection of smaller planets than previously seen by current exoplanet search methods, but stellar activity may make these theoretical limits unreachable. Astrometric jitter of a Sun-like star due to magnetic activity in its photosphere induces apparent variability in the photocenter of order 0.5 mR ⊙. This jitter creates a fundamental astrophysical noise floor preventing detection of lower-mass planets in a single spectral band. By injecting planet orbits into simulated solar data at five different passbands, we investigate mitigation of this fundamental astrometric noise using correlations across passbands. For a true solar analog and a planet at 1 au semimajor axis, the 6σ detection limit set by stellar activity for an ideal telescope at the best single passband is 0.01 Earth masses. We found that pairs of passbands with highly correlated astrometric jitter due to stellar activity, but with less motion in the redder band, enable higher-precision measurements of the common signal from the planet. Using this method improves detectable planet masses at 1 au by up to a factor of 10, corresponding to at best 0.005 Earth masses for a Sun-like star with a perfect telescope. Given these results, we recommend that future astrometry missions consider proceeding with two or more passbands to reduce noise due to stellar activity.

Keywords: Solar faculae, Exoplanet detection methods, Sunspots, Astrometry
Stacked Periodograms as a Probe of Exoplanetary Populations. Ongoing, extreme-precision Doppler radial-velocity (RV) surveys seek planets with masses less than several M ⊕; population-level studies to determine the distribution of planetary masses, however, remain difficult due to the required observational time investment, as well as challenges associated with robustly detecting the lowest-mass planets. We outline a novel approach that leverages extensive, existing RV data sets to constrain masses of exoplanet populations: stacking periodograms of RV time series across many targets. We show that an exoplanet population may be statistically identifiable in the stacked periodogram, even when individual planets do not pass the threshold of detection. We discuss analytical, statistical properties of the stacked periodogram, perform simulations to demonstrate the efficacy of the method, and investigate the influence of semistructured window functions and stellar activity. Analysis of the Lick-Carnegie Exoplanet Survey data set reveals a marginally significant (1.6σ) signal consistent with a population of exoplanets occupying 3-7 days periods with typical K between 1.6-5.1 m s-1. More detailed investigation of signals associated with stellar activity and yearly systematics may be necessary to confirm this result or detect other underlying Keplerian contributions.

Keywords: Exoplanet detection methods, Radial velocity, Lomb-Scargle periodogram
A Possible Alignment Between the Orbits of Planetary Systems and their Visual Binary Companions. Astronomers do not have a complete picture of the effects of wide-binary companions (semimajor axes greater than 100 au) on the formation and evolution of exoplanets. We investigate these effects using new data from Gaia Early Data Release 3 and the Transiting Exoplanet Survey Satellite mission to characterize wide-binary systems with transiting exoplanets. We identify a sample of 67 systems of transiting exoplanet candidates (with well-determined, edge-on orbital inclinations) that reside in wide visual binary systems. We derive limits on orbital parameters for the wide-binary systems and measure the minimum difference in orbital inclination between the binary and planet orbits. We determine that there is statistically significant difference in the inclination distribution of wide-binary systems with transiting planets compared to a control sample, with the probability that the two distributions are the same being 0.0037. This implies that there is an overabundance of planets in binary systems whose orbits are aligned with those of the binary. The overabundance of aligned systems appears to primarily have semimajor axes less than 700 au. We investigate some effects that could cause the alignment and conclude that a torque caused by a misaligned binary companion on the protoplanetary disk is the most promising explanation.

Keywords: Exoplanet evolution, Circumstellar disks, Wide binary stars, Star-planet interactions, Visual binary stars
WASP-35 and HAT-P-30/WASP-51: Reanalysis using TESS and Ground-based Transit Photometry. High-precision transit observations provide excellent opportunities for characterizing the physical properties of exoplanetary systems. These physical properties supply many pieces of information for unvealing the internal structure, external atmosphere, and dynamical history of the planets. We present revised properties of the transiting systems WASP-35 and HAT-P-30/WASP-51 through analyzing newly available TESS photometry and ground-based observations obtained at the 1 m telescope of the Yunnan Observatories as well as from the literature. The improved system parameters are consistent with previous results. Furthermore, we find that the transits of HAT-P-30b/WASP-51b show possible timing variation that cannot be explained by a decaying orbit due to tidal dissipation and the Rømer effect, while both apsidal precession and an additional perturbing body could reproduce this signal according to our comprehensive dynamical simulations. Because both systems are valuable targets that are suitable for transmission spectroscopy, we make some predictions for the atmospheric properties of WASP-35b and HAT-P-30b/WASP-51b based on the newly derived system parameters.

Keywords: Exoplanet systems, Transit timing variation method, Gaussian Processes regression, Markov chain Monte Carlo, Transit photometry
HEALPix Alchemy: Fast All-Sky Geometry and Image Arithmetic in a Relational Database for Multimessenger Astronomy Brokers. Efficient searches for electromagnetic counterparts to gravitational wave, high-energy neutrino, and gamma-ray burst events demand rapid processing of image arithmetic and geometry set operations in a database to cross-match galaxy catalogs, observation footprints, and all-sky images. Here we introduce HEALPix Alchemy, an open-source, pure Python implementation of a set of methods that enables rapid all-sky geometry calculations. HEALPix Alchemy is built upon HEALPix, a spatial indexing strategy that is widely used in astronomical databases as well as the native format of LIGO-Virgo-KAGRA gravitational-wave sky localization maps. Our approach leverages new multirange types built into the PostgreSQL 14 database engine. This enables fast all-sky queries against probabilistic multimessenger event localizations and telescope survey footprints. Questions such as "What are the galaxies contained within the 90% credible region of an event?" and "What is the rank-ordered list of the fields within an observing footprint with the highest probability of containing the event?" can be performed in less than a few seconds on commodity hardware using off-the-shelf cloud-managed database implementations without server-side database extensions. Common queries scale roughly linearly with the number of telescope pointings. As the number of fields grows into the hundreds or thousands, HEALPix Alchemy is orders of magnitude faster than other implementations. HEALPix Alchemy is now used as the spatial geometry engine within SkyPortal, which forms the basis of the Zwicky Transient Facility transient marshal, called Fritz.

Keywords: Astronomy databases, Cloud computing, Gravitational wave astronomy, Virtual observatories, Time domain astronomy
New CCD Astrometric Observations of Himalia Using Gaia DR2 in 2015-2021. The long arc and high-quality astrometric measurements of outer irregular satellites are prerequisites for improving their orbital theories and increasing the precision of their ephemerides. In order to obtain good astrometric positions of Himalia, the largest irregular satellite of Jupiter, we have processed and reduced 911 ground-based CCD frames obtained between 2015 and 2021 by three telescopes (including 1 and 2.4 m telescopes at Yunnan Observatory, and 0.8 m telescope at Purple Mountain Observatory) over 61 nights. Subtracting off the companion star of our target by constructing an effective point-spread function (ePSF) model in some CCD frames, the ePSF-subtracted technique is used to reduce the centering error. Some additional techniques are applied in data reduction to further improve positional accuracy and precision of Himalia. This includes geometric distortion correction, weighted polynomial plate models, and the precision-premium effect, since their relative positional measurements have better precision when two objects are very near (e.g., less than 60″). The star catalog Gaia DR2 is used for astrometric calibration, and theoretical positions of Himalia are retrieved from JPL Horizons ephemeris, including the satellite ephemeris Jup344 and the newest planetary ephemeris DE441. Our results show the mean (O - C)s (observed minus computed) of the positional residuals of Himalia are -0."004 and 0.″005 in R.A. and decl., respectively, and their corresponding standard deviations are about 0.″020 in each direction.

Keywords: Observational astronomy, Astronomical techniques
Stability Analysis of Earth Co-orbital Objects. In this paper, we investigate the stability of Earth co-orbital objects (ECOs) based on the torus structure. The Hamiltonian value is an index to evaluate co-orbital stability. According to topological characters of tadpole (TP), horseshoe (HS), quasi-satellite (QS), and critical compound surfaces in the torus space, the co-orbital area is divided into several regions in detail. We select 221 potential ECOs as representative samples. Numerical integration in the Sun-Earth system illustrates that most of objects above the collision line are short- or long-term stable ECOs in the QS-HS and QS-TP motions, and most of objects in the unstable region are unstable ones, which is in agreement with our semi-analytical conclusions. The stability of an ECO with a larger Hamiltonian value could be stronger. An efficient method to determine the long-term co-orbital stability of a potential ECO is proposed without long-term numerical integration. Numerical integration in the multiplanet model demonstrates that our stability analysis is still applicable for the real solar system. As an application of our stability analysis, two well-determined QS-HS ECOs above the collision line are identified and analyzed for the first time. For instance, the QS-HS state of 2019 VL5 can be sustained for more than 3000 yr, and its current HS state will be sustained for at least 800 yr.

Keywords: Small Solar System bodies, Asteroid dynamics, Orbital resonances, Close encounters, N-body simulations
The Many-faceted Light Curves of Young Disk-bearing Stars in Taurus as Seen by K2. We present a comprehensive study of the variability properties of young disk-bearing stars in the Taurus star-forming region, paralleling our previous investigation in ρ Oph and Upper Sco. A sample of 99 confirmed Taurus association members is placed in the diagnostic Q - M plane of flux asymmetry (M) and (Q), which guides our assignment of variability classes. We find a similar proportion of flux-symmetric variables in Taurus, but more bursters and fewer dippers relative to Upper Sco. The regions also differ in that the amplitudes for periodic and sources are larger in Taurus relative to the more evolved Upper Sco star/disk systems. The relationship between photometric variability patterns at optical wavelengths, which arise in the inner disk and at the stellar surface, are assessed relative to available disk inclination measurements.

Keywords: Classical T Tauri stars, Young stellar objects, Pre-main sequence stars, Protoplanetary disks, Stellar accretion, Circumstellar disks, Variable stars, Time domain astronomy
Size Distribution of Small Jupiter Trojans in the L<SUB>5</SUB> Swarm. We present an analysis of survey observations of the trailing L5 Jupiter Trojan swarm using the wide-field Hyper Suprime-Cam CCD camera on the 8.2 m Subaru Telescope. We detected 189 L5 Trojans from our survey that covered about 15 deg2 of sky with a detection limit of m  r  = 24.1 mag, and selected an unbiased sample consisting of 87 objects with absolute magnitude 14 ≲ H  r  ≤ 17 corresponding to diameter 2 km ≲ D ≲ 10 km for analysis of size distribution. We fit their differential magnitude distribution to a single-slope power law with an index α = 0.37 ± 0.01, which corresponds to a cumulative size distribution with an index of b = 1.85 ± 0.05. Combining our results with data for known asteroids, we obtained the size distribution of L5 Jupiter Trojans over the entire size range for 9 ≲ H  V  ≤ 17, and found that the size distributions of the L4 and L5 swarms agree well with each other for a wide range of sizes. This is consistent with the scenario that asteroids in the two swarms originated from the same primordial population. Based on the above results, the ratio of the total number of asteroids with D ≥ 2 km in the two swarms is estimated to be N L4/N L5 = 1.40 ± 0.15, and the total number of L5 Jupiter Trojans with D ≥ 1 km is estimated to be 1.1 × 105 by extrapolating the obtained distribution. *This research is based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. We are honored and grateful for the opportunity of observing the Universe from Maunakea, which has the cultural, historical and natural significance in Hawaii.

Keywords: Optical observation, Solar system formation, Small Solar System bodies, Jupiter trojans, Trojan asteroids
A Systematic Study about Orbit Flips of Test Particles Caused by Eccentric Von Zeipel-Lidov-Kozai Effects. The problem of orbit flips caused by eccentric von Zeipel-Lidov-Kozai effects is systematically investigated by means of three approaches, including Poincaré sections, dynamical system theory (periodic orbits and invariant manifolds), and perturbation treatments. Poincaré sections show that orbit flips are due to the existence of islands of libration centered at inclination of 90°, dynamical system theory shows that orbit flips are due to the existence of polar periodic orbits and invariant manifolds, and perturbative treatments indicate that orbit flips are due to the libration of a certain critical argument. Using these approaches, the boundaries of flipping regions in the entire parameter space are produced, and they are in excellent agreement with one another. Through analysis, the essence of flipping orbits is reached: (a) flipping orbits are a kind of quasiperiodic trajectory around polar periodic orbits and invariant manifolds at the same level of Hamiltonian provide boundaries of flipping regions, and (b) flipping orbits are a kind of resonant trajectory, and resonant width measures the size of flipping regions.

Keywords: Orbital motion, Asteroid dynamics, Orbital resonances, Gravitational interaction, Celestial mechanics, Asteroid satellites, Three-body problem, Perturbation methods
Revisiting BD-06 1339b: A Likely False Positive Caused by Stellar Activity. As long as astronomers have searched for exoplanets, the intrinsic variability of host stars has interfered with the ability to reliably detect and confirm exoplanets. One particular source of false positives is the presence of stellar magnetic or chromospheric activity that can mimic the radial velocity reflex motion of a planet. Here we present the results of a photometric data analysis for the known planet-hosting star BD -06°1339, observed by the Transiting Exoplanet Survey Satellite during Sector 6 at a cadence of 2 minutes. We discuss evidence that suggests that the observed 3.9-day periodic radial velocity signature may be caused by stellar activity rather than a planetary companion, since variability detected in the photometric data is consistent with the periodic signal. We conclude that the previously reported planetary signature is likely the result of a false-positive signal resulting from stellar activity, and we discuss the need for more data to confirm this conclusion.

Keywords: Stellar photometry, Exoplanets, Radial velocity, Stellar activity, Exoplanet astronomy, Exoplanet detection methods, Stellar rotation
Limits on the Detection of Planet Nine in the Dark Energy Survey. Studies of the clustering of the most distant Kuiper Belt objects in the outer solar system have hinted at the possible existence of a planet beyond Neptune referred to as Planet Nine (P9). Recent efforts have constrained the parameter space of the orbital elements of P9, allowing for the creation of a synthetic catalog of hypothetical P9s. By examining the potential recovery of such a catalog within numerous sky surveys, it is possible to further constrain the parameter space for P9, providing direction for a more targeted search. We examine the ability of the full six years of the Dark Energy Survey (DES) to recover a synthetic Planet Nine population presented in Brown &amp; Batygin. We find that out of 100,000 simulated objects, 11,709 cross the wide DES survey footprint of which 10,187 (87.0%) are recovered. This rules out an additional 5% of the parameter space after accounting for Planets Nine that would have been detected by both the Zwicky Transient Facility and DES.

Keywords: Planetary science, Solar system planets
L-band Integral Field Spectroscopy of the HR 8799 Planetary System. Understanding the physical processes sculpting the appearance of young gas-giant planets is complicated by degeneracies confounding effective temperature, surface gravity, cloudiness, and chemistry. To enable more detailed studies, spectroscopic observations covering a wide range of wavelengths are required. Here we present the first L-band spectroscopic observations of HR 8799 d and e and the first low-resolution wide-bandwidth L-band spectroscopic measurements of HR 8799 c. These measurements were facilitated by an upgraded LMIRCam/ALES instrument at the Large Binocular Telescope, together with a new apodizing phase plate coronagraph. Our data are generally consistent with previous photometric observations covering similar wavelengths, yet there exists some tension with narrowband photometry for HR 8799 c. With the addition of our spectra, each of the three innermost observed planets in the HR 8799 system has had its spectral energy distribution measured with integral field spectroscopy covering ~0.9-4.1 μm. We combine these spectra with measurements from the literature and fit synthetic model atmospheres. We demonstrate that the bolometric luminosity of the planets is not sensitive to the choice of model atmosphere used to interpolate between measurements and extrapolate beyond them. Combining luminosity with age and mass constraints, we show that the predictions of evolutionary models are narrowly peaked for effective temperature, surface gravity, and planetary radius. By holding these parameters at their predicted values, we show that more flexible cloud models can provide good fits to the data while being consistent with the expectations of evolutionary models.

Keywords: Exoplanet detection methods, Exoplanet atmospheres, Exoplanet evolution
Confirmation of the Long-period Planet Orbiting Gliese 411 and the Detection of a New Planet Candidate. We perform a detailed characterization of the planetary system orbiting the bright, nearby M dwarf Gliese 411 using radial velocities gathered by APF, HIRES, SOPHIE, and CARMENES. We confirm the presence of a signal with a period near 2900 days that has been disputed as either a planet or a long-period stellar magnetic cycle. An analysis of activity metrics including the H α  and $\mathrm{log}^{\prime} {R}_{\mathrm{HK}}$ indices supports the interpretation that the signal corresponds to a Neptune-like planet, GJ 411 c. An additional signal near 215 days was previously dismissed as an instrumental systematic, but we find that a planetary origin cannot be ruled out. With a semimajor axis of 0.5142 ± 0.0042 au, this candidate's orbit falls between those of its companions and is located beyond the outer edge of the system's habitable zone (determined using the moist greenhouse and maximum greenhouse limits in Kopparapu et al. 2013). It has a minimum mass of 3.89 ± 0.84 M ⊕, giving a radial-velocity amplitude of 0.81 ± 0.18 m s-1. If confirmed, this would be one of the lowest-amplitude planet detections from any of these four instruments. Our analysis of the joint radial-velocity data set also provides tighter constraints on the orbital parameters for the previously known planets. Photometric data from TESS do not show any signs of a transit event. However, the outermost planet and candidate are prime targets for future direct imaging missions, and GJ 411 c may be detectable via astrometry.

Keywords: Exoplanet detection methods, Radial velocity, Exoplanets, Stellar activity
Search for Stellar Flybys in the Sco-Cen OB Association with the Gaia DR2. High-contrast imaging studies of debris disks have revealed a significant diversity in their morphologies, including large-scale asymmetries. Theories involving stellar flybys, an external source of gravitational disturbance, have offered a plausible explanation for the origin of these morphological variations. Our study is an experiment to gain empirical evidence that has been lacking from such theories. We explore this paradigm by using astrometric and radial velocity measurements from the Gaia DR2 and ground-based observations to trace the trajectories of 625 stars in the Sco-Cen OB association from 5 Myr in the past to 2 Myr in the future. We identified 119 stars that had at least one past flyby event occurring within one Hill radius, and 23 of these experienced flybys within 0.5 Hill radii. We found no evidence of a significant correlation between the presence of flyby events and infrared excess detections, although the sample is not uniformly sensitive to infrared excess emission. Ten stars that had past flyby events host resolved circumstellar disks that appear relatively symmetric in the existing data except for the circumbinary disk surrounding HD 106906. We determined the trajectory and relative velocity of each of these flyby events and compared these to the geometry of the spatially resolved disks. Future work is needed to measure the kinematics of lower-mass stars and to improve sensitivity to circumstellar disks for the entire sample.

Keywords: Celestial mechanics, Debris disks, Close encounters, Circumstellar disks