Sazuna/UAT_keywords huggingface dataset:
Dynamics of Planetary Systems within Star Clusters: Aspects of the Solar System's Early Evolution. Most planetary systems—including our own—are born within stellar clusters, where interactions with neighboring stars can help shape the system architecture. This paper develops an orbit-averaged formalism to characterize the cluster's mean-field effects, as well as the physics of long-period stellar encounters. Our secular approach allows for an analytic description of the dynamical consequences of the cluster environment on its constituent planetary systems. We analyze special cases of the resulting Hamiltonian, corresponding to eccentricity evolution driven by planar encounters, as well as hyperbolic perturbations upon dissipative disks. We subsequently apply our results to the early evolution of our solar system, where the cluster's collective potential perturbs the solar system's plane, and stellar encounters act to increase the velocity dispersion of the Kuiper Belt. Our results are twofold. First, we find that cluster effects can alter the mean plane of the solar system by ≲1° and are thus insufficient to explain the ψ ≈ 6° obliquity of the Sun. Second, we delineate the extent to which stellar flybys excite the orbital dispersion of the cold classical Kuiper Belt and show that while stellar flybys may grow the cold belt's inclination by the observed amount, the resulting distribution is incompatible with the data. Correspondingly, our calculations place an upper limit on the product of the stellar number density and residence time of the Sun in its birth cluster, η τ ≲ 2 × 104 Myr pc-3.

Keywords: Celestial mechanics, Young star clusters, Kuiper belt
Resonances in Nonaxisymmetric Gravitational Potentials. We study sectoral resonances of the form jκ = m(n - Ω) around a nonaxisymmetric body with spin rate Ω, where κ and n are the epicyclic frequency and mean motion of a particle, respectively, where j &gt; 0 and m (&lt;0 or &gt;0) are integers, j being the order of the resonance. This describes n/Ω ∼ m/(m - j) resonances inside and outside the corotation radius, as well as prograde and retrograde resonances. Results are as follows: (1) the kinematics of a periodic orbit depends only on (m', j'), the irreducible (relatively prime) version of (m, j). In a rotating frame, the periodic orbit has j' braids, $| m^{\prime} | $ identical sectors, and $| m^{\prime} | (j^{\prime} -1)$ self-crossing points; (2) thus, Lindblad resonances (with j = 1) are free of self-crossing points; (3) resonances with the same j' and opposite m' have the same kinematics, and are called twins; (4) the order of a resonance at a given n/Ω depends on the symmetry of the potential. A potential that is invariant under a 2π/k-rotation creates only resonances with m multiple of k; (5) resonances with the same j and opposite m have the same kinematics and same dynamics, and are called true twins; (6) A retrograde resonance (n/Ω &lt; 0) is always of higher order than its prograde counterpart (n/Ω &gt; 0); (7) the resonance strengths can be calculated in a compact form with the classical operators used in the case of a perturbing satellite. Applications to Chariklo and Haumea are made.

Keywords: Centaur group, Planetary rings, Orbital resonances, Galaxy disks, Gravitational interaction, Trans-Neptunian objects
Star Formation in Isolated Dwarf Galaxies Hosting Tidal Debris: Extending the Dwarf-Dwarf Merger Sequence. Like massive galaxies, dwarf galaxies are expected to undergo major mergers with other dwarfs. However, the end state of these mergers and the role that merging plays in regulating dwarf star formation are uncertain. Using imaging from the Hyper Suprime-Cam Subaru Strategic Program, we construct a sample of dwarf-dwarf mergers and examine the star formation and host properties of the merging systems. These galaxies are selected via an automated detection algorithm from a sample of 6875 spectroscopically selected isolated dwarf galaxies at z &lt; 0.12 and $\mathrm{log}({M}_{\star }/{M}_{\odot })\lt 9.6$ from the Galaxy and Mass Assembly and Sloan Digital Sky Survey spectroscopic campaigns. We find a total tidal feature detection fraction of 3.29% (6.1% when considering only galaxies at z &lt; 0.05). The tidal feature detection fraction rises strongly as a function of star formation activity; 15%-20% of galaxies with extremely high Hα equivalent width (Hα EW &gt; 250 Å) show signs of tidal debris. Galaxies that host tidal debris are also systematically bluer than the average galaxy at fixed stellar mass. These findings extend the observed dwarf-dwarf merger sequence with a significant sample of dwarf galaxies, indicating that star formation triggered in mergers between dwarf galaxies continues after coalescence.

Keywords: Observational astronomy, Blue compact dwarf galaxies, Dwarf galaxies, Star formation, Galaxy mergers, Galaxy evolution
TESS Phase Curve of the Hot Jupiter WASP-19b. We analyze the phase curve of the short-period transiting hot Jupiter system WASP-19, which was observed by the Transiting Exoplanet Survey Satellite (TESS) in Sector 9. WASP-19 is one of only five transiting exoplanet systems with full-orbit phase curve measurements at both optical and infrared wavelengths. We measure a secondary eclipse depth of ${470}_{-110}^{+130}$ ppm and detect a strong atmospheric brightness modulation signal with a semiamplitude of 319 ± 51 ppm. No significant offset is detected between the substellar point and the region of maximum brightness on the dayside. There is also no significant nightside flux detected, which is in agreement with the nightside effective blackbody temperature of ${1090}_{-250}^{+190}$ derived from the published Spitzer phase curves for this planet. Placing the eclipse depth measured in the TESS bandpass alongside the large body of previous values from the literature, we carry out the first atmospheric retrievals of WASP-19b's secondary eclipse spectrum using the SCARLET code. The retrieval analysis indicates that WASP-19b has a dayside atmosphere consistent with an isotherm at T = 2240 ± 40 K and a visible geometric albedo of 0.16 ± 0.04, indicating significant contribution from reflected starlight in the TESS bandpass and moderately efficient day-night heat transport.

Keywords: Hot Jupiters, Broad band photometry, Exoplanets
Discovery of Two Nearby Post-T Tauri Stellar Associations. In this work we report the discovery of two new stellar associations in close vicinity of the Sun at roughly 180 and 150 pc. These two associations, u Tau assoc and e Tau assoc, were detected based on their clustering in a multi-dimensional parameter space including α, δ, μα, μδ, and ϖ of Gaia. The fitting of pre-main-sequence model isochrones in their color-magnitude diagrams suggests that the two associations are of about 50 Myr old and the group members lower than ∼0.8 M⊙ are at the stage of post-T Tauri.

Keywords: Pre-main sequence stars, Young star clusters, Pre-main sequence
A Search for Transiting Planets in the Globular Cluster M4 with K2: Candidates and Occurrence Limits. We perform a search for transiting planets in the NASA K2 observations of the globular cluster (GC) M4. This search is sensitive to larger orbital periods (P ≲ 35 days, compared to the previous best of P ≲ 16 days), and at the shortest periods, smaller planet radii (Rp ≳ 0.3 RJ, compared to the previous best of Rp ≳ 0.8 RJ) than any previous search for GC planets. Seven planet candidates are presented. An analysis of the systematic noise in our data shows that most, if not all, of these candidates are likely false alarms. We calculate planet occurrence rates assuming our highest significance candidate is a planet and occurrence rate upper limits assuming no detections. We calculate 3σ occurrence rate upper limits of 6.1% for 0.71-2 RJ planets with 1-36 days periods and 16% for 0.36-0.71 RJ planets with 1-10 days periods. The occurrence rates from Kepler, TESS, and radial velocity studies of field stars are consistent with both a nondetection of a planet and detection of a single hot Jupiter in our data. Comparing to previous studies of GCs, we are unable to place a more stringent constraint than Gilliland et al. for the radius-period range they were sensitive to, but do place tighter constraints than both Weldrake et al. and Nascimbeni et al. for the large-radius regimes to which they were sensitive.

Keywords: Globular star clusters, Hot Jupiters, Transit photometry, Exoplanets
Mineralogical Criteria for the Parent Asteroid of the "Carbonaceous" Achondrite NWA 6704. The unique achondrite meteorite Northwest Africa (NWA) 6704 and its paired samples are fragments of an unknown parent asteroid that experienced large-scale igneous melting early in our solar system's history. The geochemistry and mineralogy of NWA 6704 show that its parent asteroid has affinities with carbonaceous chondrites and that the precursor materials were relatively oxidized. While large-scale melting has affected the meteorite, there is no evidence for equilibration with a metallic melt. NWA 6704 paired meteorites therefore provide insights into the evolution of planetesimals and bodies that accreted from source materials, possibly in the ice-rich outer solar system. Currently, we lack an understanding of the distribution of potential parent asteroids of the NWA 6704 meteorites. We have undertaken a detailed multiwavelength (0.35-25 μm) spectroscopic and geochemical investigation of NWA 6704 to provide constraints on the potential parent asteroids of these enigmatic meteorites. In comparison with asteroid spectra, NWA 6704 is similar to the S(VI) subtypes of the S-asteroid complex. By using the Bus-DeMeo Taxonomic Classifier, we determine that NWA 6704 has affinities toward V-type (Vesta type) asteroids. We have determined that the parent asteroid of NWA 6704 would be a V-type asteroid that is not dynamically linked to Vesta and also fall in the S(VI) subtype of the Band I center versus Band area ratio diagram. A search in the literature for potential parent bodies yielded one asteroid, (34698) 2001 OD22, as a possible candidate.

Keywords: Asteroids, Achondrites, Infrared astronomy, Main belt asteroids, Infrared telescopes, Spectroscopy, Meteorites, Asteroid belt
Diffuser-assisted Infrared Transit Photometry for Four Dynamically Interacting Kepler Systems. We present ground-based infrared transit observations for four dynamically interacting Kepler planets, including Kepler-29b, Kepler-36c, KOI-1783.01, and Kepler-177c, obtained using the Wide-field Infrared Camera on the Hale 200 inch telescope at Palomar Observatory. By utilizing an engineered diffuser and custom guiding software, we mitigate time-correlated telluric and instrumental noise sources in these observations. We achieve an infrared photometric precision comparable to or better than that of space-based observatories such as the Spitzer Space Telescope, and detect transits with greater than 3σ significance for all planets. For Kepler-177c (J = 13.9), our measurement uncertainties are only 1.2 times the photon noise limit and 1.9 times better than the predicted photometric precision for Spitzer IRAC photometry of this same target. We find that a single transit observation obtained 4-5 yr after the end of the original Kepler mission can reduce dynamical mass uncertainties by as much as a factor of 3 for these systems. Additionally, we combine our new observations of KOI-1783.01 with information from the literature to confirm the planetary nature of this system. We discuss the implications of our new mass and radius constraints in the context of known exoplanets with low incident fluxes, and we note that Kepler-177c may be a more massive analog to the currently known super-puffs given its core mass (3.8 $\,\pm \,0.9{M}_{\oplus }$ ) and large gas-to-core ratio (2.8 ± 0.7). Our demonstrated infrared photometric performance opens up new avenues for ground-based observations of transiting exoplanets previously thought to be restricted to space-based investigation.

Keywords: Exoplanet astronomy, Ground-based astronomy, Exoplanet systems, Exoplanet dynamics
Detrending Exoplanetary Transit Light Curves with Long Short-term Memory Networks. The precise derivation of transit depths from transit light curves is a key component for measuring exoplanet transit spectra, and henceforth for the study of exoplanet atmospheres. However, it is still deeply affected by various kinds of systematic errors and noise. In this paper we propose a new detrending method by reconstructing the stellar flux baseline during transit time. We train a probabilistic long short-term memory (LSTM) network to predict the next data point of the light curve during the out-of-transit, and use this model to reconstruct a transit-free light curve—i.e., including only the systematics—during the in-transit. By making no assumption about the instrument, and using only the transit ephemeris, this provides a general way to correct the systematics and perform a subsequent transit fit. The name of the proposed model is TLCD-LSTM, standing for transit light-curve detrending-LSTM. Here we present the first results on data from six transit observations of HD 189733b with the IRAC camera on board the Spitzer Space Telescope, and discuss some of its possible further applications.

Keywords: Photometric systems, Neural networks, Astronomy data analysis, Extrasolar gaseous giant planets, Exoplanet atmospheres
Galaxy Clusters Selected via the Sunyaev-Zel'dovich Effect in the SPTpol 100-square-degree Survey. We present a catalog of galaxy cluster candidates detected in 100 square degrees surveyed with the SPTpol receiver on the South Pole Telescope. The catalog contains 89 candidates detected with a signal-to-noise ratio greater than 4.6. The candidates are selected using the Sunyaev-Zel'dovich effect at 95 and 150 GHz. Using both space- and ground-based optical and infrared telescopes, we have confirmed 81 candidates as galaxy clusters. We use these follow-up images and archival images to estimate photometric redshifts for 66 galaxy clusters and spectroscopic observations to obtain redshifts for 13 systems. An additional two galaxy clusters are confirmed using the overdensity of near-infrared galaxies only and are presented without redshifts. We find that 15 candidates (18% of the total sample) are at redshift z ≥ 1.0, with a maximum confirmed redshift of ${z}_{\max }=1.38\pm 0.10$ . We expect this catalog to contain every galaxy cluster with ${M}_{500c}\gt 2.6\times {10}^{14}{M}_{\odot }{{h}}_{70}^{-1}$ and z &gt; 0.25 in the survey area. The mass threshold is approximately constant above z = 0.25, and the complete catalog has a median mass of approximately ${M}_{500c}=2.7\times {10}^{14}{M}_{\odot }{{h}}_{70}^{-1}$ . Compared to previous SPT works, the increased depth of the millimeter-wave data (11.2 and 6.5 μK-arcmin at 95 and 150 GHz, respectively) makes it possible to find more galaxy clusters at high redshift and lower mass.

Keywords: Galaxy clusters, Observational cosmology, Large-scale structure of the universe
Near-ultraviolet Transmission Spectroscopy of HD 209458b: Evidence of Ionized Iron Beyond the Planetary Roche Lobe. The inflated transiting hot Jupiter HD 209458b is one of the best studied objects since the beginning of exoplanet characterization. Transmission observations of this system between the mid-infrared and the far-ultraviolet have revealed the signature of atomic, molecular, and possibly aerosol species in the lower atmosphere of the planet, as well as escaping hydrogen and metals in the upper atmosphere. From a re-analysis of near-ultraviolet transmission observations of HD 209458b we detect ionized iron (Fe+) absorption in a 100 Å-wide range around 2370 Å, lying beyond the planetary Roche lobe. However, we do not detect absorption of equally strong Fe+ lines expected to be around 2600 Å. Further, we find no evidence for absorption by neutral magnesium (Mg), ionized magnesium (Mg+), nor neutral iron (Fe). These results avoid the conflict with theoretical models previously found by Vidal-Madjar et al., which detected Mg but did not detect Mg+ from this same data set. Our results indicate that hydrodynamic escape is strong enough to carry atoms as heavy as iron beyond the planetary Roche lobe, even for planets less irradiated than the extreme ultra-hot Jupiters such as WASP-12 b and KELT-9 b. The detection of iron and nondetection of magnesium in the upper atmosphere of HD 209458b can be explained by a model in which the lower atmosphere forms (hence, sequesters) primarily magnesium-bearing condensates, rather than iron condensates. This is suggested by current microphysical models. The inextricable synergy between upper- and lower-atmosphere properties highlights the value of combining observations that probe both regions.

Keywords: Radiative transfer, Exoplanet atmospheres, Transmission spectroscopy
The Young Planet DS Tuc Ab Has a Low Obliquity. The abundance of short-period planetary systems with high orbital obliquities relative to the spin of their host stars is often taken as evidence that scattering processes play important roles in the formation and evolution of these systems. More recent studies have suggested that wide binary companions can tilt protoplanetary disks, inducing a high stellar obliquity that form through smooth processes like disk migration. DS Tuc Ab, a transiting planet with an 8.138 day period in the 40 Myr Tucana-Horologium association, likely orbits in the same plane as its now-dissipated protoplanetary disk, enabling us to test these theories of disk physics. Here, we report on Rossiter-McLaughlin observations of one transit of DS Tuc Ab with the Planet Finder Spectrograph on the Magellan Clay Telescope at Las Campanas Observatory. We confirm the previously detected planet by modeling the planet transit and stellar activity signals simultaneously. We test multiple models to describe the stellar activity-induced radial velocity variations over the night of the transit, finding the obliquity to be low: λ = 12° ± 13°, which suggests that this planet likely formed through smooth disk processes and its protoplanetary disk was not significantly torqued by DS Tuc B. The specific stellar activity model chosen affects the results at the ≈5° level. This is the youngest planet to be observed using this technique; we provide a discussion on best practices to accurately measure the observed signal of similar young planets.

Keywords: Exoplanet dynamics, Starspots, High resolution spectroscopy, Exoplanets
Survey of Very Broad Diffuse Interstellar Bands. This paper considers a very special set of a few interstellar features—broad diffuse interstellar bands (DIBs) at 4430, 4882, 5450, 5779, and 6175 ÅÅ. The set is small, and measurements of equivalent widths of these DIBs are challenging because of severe stellar, interstellar, and sometimes, also telluric contaminations inside their broad profiles. Nevertheless, we demonstrate that they do correlate pretty tightly (DIBs 4882 and 5450 to a lesser extent though) with other narrower diffuse bands, as well as with the color excess E(B-V). The studied broad DIBs correlate well with both interstellar molecule CH and interstellar K i, i.e., it is hardly possible to verify whether the environments, facilitating the formation of very broad DIB carriers, are dominated by either molecular or atomic gas as both these species likely occupy the same volume.

Keywords: Neutral hydrogen clouds, Interstellar medium, Diffuse interstellar clouds
Exploratory Spectroscopy of Magnetic Cataclysmic Variables Candidates and Other Variable Objects. II. This is the second paper of a series presenting our search for magnetic cataclysmic variables (mCVs) among candidates selected mostly from the Catalina Real-Time Transient Survey. We present the identification spectra, obtained at the SOAR Telescope, as well as magnitudes and Gaia distances for 45 objects. Of these, 39 objects are identified as CVs, from which 8 targets show observational characteristics of mCVs, being 7 polars and 1 intermediate polar. The remaining 31 CVs in our sample are probably non-magnetic systems, in low (22 systems) or high (9 systems) accretion states. Six targets of the sample are not CVs (5 active galactic nuclei and 1 T Tauri star). Among the 8 objects with mCV spectra, 6 are new classifications. Three polars were observed in low-accretion state, either revealing photospheric features of the secondary star and allowing the estimation of their spectral type, or presenting Hβ Zeeman components associated to the white dwarf (WD) magnetic field. In addition to the results obtained in the first paper of the series, and depending on the confirmation of these classifications by observational follow-up, our results would increase the sample of known polars by about 9%.

Keywords: Interacting binary stars, Dwarf novae, DQ Herculis stars, Spectroscopy, Magnetic variable stars, Cataclysmic variable stars, AM Herculis stars
Confirmation of WASP-107b's Extended Helium Atmosphere with Keck II/NIRSPEC. We present the detection of helium in the extended atmosphere of the sub-Saturn WASP-107b using high-resolution (R ≈ 25,000) near-infrared spectra from Keck II/Near Infrared Echelle Spectrograph (NIRSPEC). We find peak excess absorption of 7.26% ± 0.24% (30σ) centered on the He i triplet at 10833 Å. The amplitude and shape of the helium absorption profile is in excellent agreement with previous observations of escaping helium from this planet made by CARMENES and the Hubble Space Telescope. This suggests there is no significant temporal variation in the signature of escaping helium from the planet over a two year baseline. This result demonstrates Keck II/NIRSPEC's ability to detect atmospheric escape in exoplanets, making it a useful instrument to further our understanding of the evaporation of exoplanetary atmospheres via ground-based observations of He i.

Keywords: Observational astronomy, Exoplanets
OGLE-2015-BLG-1771Lb: A Microlens Planet Orbiting an Ultracool Dwarf?. We report the discovery and the analysis of the short ( ${t}_{{\rm{E}}}\lt 5$ days) planetary microlensing event, OGLE-2015-BLG-1771. The event was discovered by the Optical Gravitational Lensing Experiment, and the planetary anomaly (at I ∼ 19) was captured by The Korea Microlensing Telescope Network. The event has three surviving planetary models that explain the observed light curves, with planet-host mass ratio q ∼ 5.4 × 10-3, 4.5 × 10-3 and 4.5 × 10-2, respectively. The first model is the best-fit model, while the second model is disfavored by Δχ2 ∼ 3. The last model is strongly disfavored by Δχ2 ∼ 15 but not ruled out. A Bayesian analysis using a Galactic model indicates that the first two models are probably composed of a Saturn-mass planet orbiting a late M dwarf, while the third one could consist of a super-Jovian planet and a mid-mass brown dwarf. The source-lens relative proper motion is μrel ∼ 9 mas yr-1, so the source and lens could be resolved by current adaptive-optics instruments in 2020 if the lens is luminous.

Keywords: Gravitational microlensing exoplanet detection