Sazuna/UAT_keywords huggingface dataset:
Calibrating the Galactic Cepheid Period-Luminosity Relation from the Maximum-likelihood Technique. We present a realization of the maximum-likelihood technique, which is one of the latest modifications of the Baade-Becker-Wesselink method. Our approach is based on nonlinear calibrations of the effective temperature and bolometric correction, which take into account metallicity and surface gravity. It allows one to estimate the key Cepheid parameters, the distance modulus, and the interstellar reddening, combining photometric and spectroscopic data (including the effective temperature data). This method is applied to a sample of 44 Galactic Cepheids for which multiphase temperature measurements are available. The additional data correction is performed to subtract the impact of the component in binary/multiple systems. We also study the effect of shock waves, whose presence in the stellar atmosphere distorts the observational data and leads to systematic errors in the obtained parameters. We determine the optimal restriction on the input data to eliminate this effect. This restriction provides accurate period-radius and period-luminosity relations that are consistent with the results in previous studies. We found the following relations: log R = (0.68 ± 0.03) · log P + (1.14 ± 0.03), Mv = - (2.67 ± 0.16) · (log P - 1) - (4.14 ± 0.05).

Keywords: Cepheid variable stars, Cepheid distance
2D Retrieval Frameworks for Hot Jupiter Phase Curves. Spectroscopic phase curves provide unique access to the three-dimensional properties of transiting exoplanet atmospheres. However, a modeling framework must be developed to deliver accurate inferences of atmospheric properties for these complex data sets. Here, we develop an approach to retrieve temperature structures and molecular abundances from phase curve spectra at any orbital phase. In the context of a representative hot Jupiter with a large day-night temperature contrast, we examine the biases in typical one-dimensional (1D) retrievals as a function of orbital phase/geometry, compared to two-dimensional (2D) models that appropriately capture the disk-integrated phase geometry. We guide our intuition by applying our new framework on a simulated Hubble Space Telescope (HST)+Spitzer phase curve data set in which the "truth" is known, followed by an application to the spectroscopic phase curve of the canonical hot Jupiter, WASP-43b. We also demonstrate the retrieval framework on simulated James Webb Space Telescope (JWST) phase curve observations. We apply our new geometric framework to a joint fit of all spectroscopic phases, assuming longitudinal molecular abundance homogeneity, resulting in an a factor of 2 improvement in abundances precision when compared to individual phase constraints. With a 1D retrieval model on simulated HST+Spitzer data, we find strongly biased molecular abundances for CH4 and CO2 at most orbital phases. With 2D, the day and night profiles retrieved from WASP-43b remain consistent throughout the orbit. JWST retrievals show that a 2D model is strongly favored at all orbital phases. Based on our new 2D retrieval implementation, we provide recommendations on when 1D models are appropriate and when more complex phase geometries involving multiple TP profiles are required to obtain an unbiased view of tidally locked planetary atmospheres.

Keywords: Exoplanet atmospheric composition , Planetary atmospheres, Bayesian statistics, Exoplanet atmospheres
Ultra-short-period Planets Are Stable against Tidal Inspiral. It has been unambiguously shown both in individual systems and at the population level that hot Jupiters experience tidal inspiral before the end of their host stars' main-sequence lifetimes. Ultra-short-period (USP) planets have orbital periods P &lt; 1 day, rocky compositions, and are expected to experience tidal decay on similar timescales to hot Jupiters if the efficiency of tidal dissipation inside their host stars parameterized as ${Q}_{* }^{{\prime} }$ is independent of P and/or secondary mass Mp. Any difference between the two classes of systems would reveal that a model with constant ${Q}_{* }^{{\prime} }$ is insufficient. If USP planets experience tidal inspiral, then USP planet systems will be relatively young compared to similar stars without USP planets. Because it is a proxy for relative age, we calculate the Galactic velocity dispersions of USP planet candidate host and non-host stars using data from Gaia Data Release 2 supplemented with ground-based radial velocities. We find that main-sequence USP planet candidate host stars have kinematics consistent with similar stars in the Kepler field without observed USP planets. This indicates that USP planet hosts have similar ages to field stars and that USP planets do not experience tidal inspiral during the main-sequence lifetimes of their host stars. The survival of USP planets requires that ${Q}_{* }^{{\prime} }$ ≳ 107 at P ≈ 0.7 day and ${M}_{{\rm{p}}}\approx 2.6\,{M}_{\oplus }$ . This result demands that ${Q}_{* }^{{\prime} }$ depend on the orbital period and/or mass of the secondary in the range $0.5\,\mathrm{day}\lesssim P\lesssim 5$ days and $1\,{M}_{\oplus }\lesssim {M}_{{\rm{p}}}\lesssim 1000\,{M}_{\oplus }$ .

Keywords: Exoplanet dynamics, Stellar ages, Exoplanets, Exoplanet evolution, Exoplanet tides, Tidal interaction
Secular Resonances in Nonrestricted Hierarchical Triple Systems. In this paper, the averaged Hamiltonian of a nonrestricted hierarchical triple system truncated at the third order is investigated. First, each secular resonant term is studied. For the well-studied secular quadrupole theory, it is analytically reformulated in a different manner in our work. The resonance width is numerically determined and displayed on the $\sqrt{1-{e}_{1}^{2}}-\sqrt{1-{e}_{2}^{2}}$ plane (also denoted as the ${\widetilde{e}}_{1}-{\widetilde{e}}_{2}$ plane). In terms of the octupole terms, we show that for a near-planar configuration of the system, considerable variations of both the eccentricities of the inner and outer orbits can be generated by a single resonant term. The resonance width for every secular resonant angle from the octupole terms is also numerically determined and displayed on the ${\widetilde{e}}_{1}-{\widetilde{e}}_{2}$ plane. The results show that an orbit flip with a near-perpendicular initial mutual inclination is possible for each secular resonance. By displaying the resonance widths of different resonant terms on the same ${\widetilde{e}}_{1}-{\widetilde{e}}_{2}$ plane, we intuitively show the overlap of different secular resonances. Then, the full averaged Hamiltonian with both quadrupole and octupole terms is investigated using the Poincaré surface of section, with a special focus on the orbit flip. For the cases we exploited, we find that the near-planar flip of the inner orbit can be either regular or chaotic while the outer orbit flip is generally chaotic.

Keywords: Exoplanet dynamics, Celestial mechanics, Three-body problem, Orbital resonances
Introducing a New Spitzer Master BLISS Map to Remove the Instrument Systematic Phase-curve-parameter Degeneracy, as Demonstrated by a Reanalysis of the 4.5 μm WASP-43b Phase Curve. While Spitzer Infrared Array Camera (IRAC) systematics are generally well understood, each data set can provide its own challenges that continue to teach us about the underlying functional form of these systematics. Multiple groups have analyzed the phase curves of WASP-43b with varying detrending techniques, each obtaining different results. In this work, we take another look at WASP-43b while exploring the degenerate relation between Bilinearly Interpolated Subpixel Sensitivity (BLISS) mapping, point response function (PRF)-FWHM detrending, and phase curve parameters. We find that there is a strong correlation between the detrending parameters in the two models, and best-fit phase curve amplitudes vary strongly when the data are temporally binned. To remove this degeneracy, we present a new Gaussian centroided intrapixel sensitivity map (hereafter fixed sensitivity map), generated using 3,712,830 exposures spanning 5 yr, for a variety of aperture sizes at 4.5 μm. We find evidence for time variability in the sensitivity at 3.6 μm and do not generate a visit-independent map for this channel. With the fixed 4.5 μm intrapixel sensitivity map, the best fits for WASP-43b no longer vary strongly with bin size and PRF-FWHM detrending is no longer required to remove correlated noise. For data sets that do not fall completely within the sweet spot, temporal binning should not be used in the analysis of Spitzer phase curves. We confirm nightside emission for WASP-43b with a disk-integrated nightside temperature of 806 ± 48 K at 4.5 μm. The 4.5 μm maps are available at github.com/kevin218/POET.

Keywords: Exoplanet astronomy, Exoplanet atmospheres, Exoplanet tides, Hot Jupiters
The Improved Orbit Solution and Component Masses of bet LMi. bet LMi is a double-lined visual binary with an orbital period of ∼39 yr. Via a simultaneous fitting to both astrometric and radial velocity measurements, we give a complete and improved orbit solution with high precision. Then, the component masses are precisely determined as 2.98 ± 0.10 M⊙ and 1.92 ± 0.04 M⊙ with a relative precision of ∼3%, respectively. The orbital parallax is determined to be 19.6 ± 0.2 mas, which is two times more precise than Hipparcos parallax. With the known apparent magnitudes and magnitude difference of the components, we derive the luminosity of the components as 50.7 ± 1.8 L⊙ and 9.1 ± 4.1 L⊙. The estimated radii of the components are 9.4 ± 0.3 R⊙ and 3.7 ± 1.5 R⊙.

Keywords: Fundamental parameters of stars, Visual binary stars, Binary stars, Spectroscopic binary stars
The Relation of the Alpha Persei Star Cluster with the Nearby Stellar Stream. A map of 100° on a side extracted from Gaia DR2 and centered on Alpha Persei reveals two distinct structures—the Alpha Persei star cluster and a conspicuous stellar stream, as widely documented in recent literature. In this work we employ DBSCAN to assess individual stars' membership and attempt at separating stars belonging to the cluster and to the stream from the general field. In turn, we characterize the stream and investigate its relation with the cluster. The stream population turned out to be significantly older (5 ± 1 Gyr) than the cluster, and to be positioned ∼90 pc away from the cluster, in its background. The stream exhibits a sizeable thickness of ∼180 pc in the direction of the line of view. Finally, the stream harbors a prominent population of white dwarf stars. We estimated an upper limit of the stream mass of ∼6000M⊙. The stream would therefore be the leftover of a relatively massive old cluster. The surface density map of Alpha Persei indicates the presence of tidal tails. While it is tempting to ascribe their presence to the interaction with the disrupting old star cluster, we prefer to believe, conservatively, they are of Galactic origin.

Keywords: Open star clusters, Astrostatistics techniques, White dwarf stars, Star clusters
SPISEA: A Python-based Simple Stellar Population Synthesis Code for Star Clusters. We present Stellar Population Interface for Stellar Evolution and Atmospheres (SPISEA), an open-source Python package that simulates simple stellar populations. The strength of SPISEA is its modular interface which offers the user control of 13 input properties including (but not limited to) the initial mass function, stellar multiplicity, extinction law, and the metallicity-dependent stellar evolution and atmosphere model grids used. The user also has control over the initial-final mass relation in order to produce compact stellar remnants (black holes, neutron stars, and white dwarfs). We demonstrate several outputs produced by the code, including color-magnitude diagrams, HR-diagrams, luminosity functions, and mass functions. SPISEA is object-oriented and extensible, and we welcome contributions from the community. The code and documentation are available on GitHub (https://github.com/astropy/SPISEA) and ReadtheDocs (https://spisea.readthedocs.io/en/latest/), respectively.

Keywords: Stellar populations, Open source software, Astronomy software, Star clusters
Transient Jupiter Co-orbitals from Solar System Sources. We demonstrate dynamical pathways from main-belt asteroid and Centaur orbits to those in co-orbital motion with Jupiter, including the retrograde (inclination i &gt; 90°) state. We estimate that, at any given time, there should be ∼1 km-scale or larger escaped asteroid in a transient direct (prograde) orbit with semimajor axis near that of Jupiter's (a ≃ aJ), with proportionally more smaller objects as determined by their size distribution. Most of these objects would be in the horseshoe dynamical state, and are hard to detect due to their moderate eccentricities (spending most of their time beyond 5 au) and longitudes relative to Jupiter being spread nearly all over the sky. We also show that ≈1% of the transient asteroid co-orbital population is on retrograde orbits with Jupiter. This population, like the recently identified asteroid (514107) 2015 BZ509, can spend millions of years with a ≃ aJ including tens or hundreds of thousands of years formally in the retrograde 1:-1 co-orbital resonance. Escaping near-Earth asteroids (NEAs) are thus likely the precursors of the handful of known high-inclination objects with a ≃ aJ. We compare the production of Jovian co-orbitals from escaping NEAs with those from incoming Centaurs. We find that temporary direct co-orbitals are likely dominated by Centaur capture, but we only find production of (temporary) retrograde Jovian co-orbitals (including very long-lived ones) from the NEA source. We postulate that the primordial elimination of the inner solar system's planetesimal population could provide a supply route for a metastable outer solar system reservoir for the high-inclination Centaurs.

Keywords: Inclination, Orbital motion, Asteroids, Orbital resonances, Jupiter trojans, Celestial mechanics
Exploring the Mass-loss Histories of the Red Supergiants. We report mid- to far-infrared imaging and photometry from 7 to 37 μm with SOFIA/FORCAST and 2 μm adaptive optics imaging with LBTI/LMIRCam of a large sample of red supergiants (RSGs) in four Galactic clusters: RSGC1, RSGC2 = Stephenson 2, RSGC3, and NGC 7419. The RSGs in these clusters cover their expected range in luminosity and initial mass from ≈9 to more than 25 M⊙. The population includes examples of very late-type RSGs such as MY Cep, which may be near the end of the RSG stage, high-mass-losing maser sources, yellow hypergiants, and post-RSG candidates. Many of the stars and almost all of the most luminous have spectral energy distributions (SEDs) with extended infrared excess radiation at the longest wavelengths. To best model their SEDs, we use the DUSTY code with a variable radial density distribution function to estimate their mass-loss rates. Our $\dot{M}$ -luminosity relation for 42 RSGs basically follows the classical de Jager curve, but at luminosities below 105 ${L}_{\odot }$ , we find a significant population of RSGs with $\dot{M}$ below the de Jager relation. At luminosities above 105 L⊙, there is a rapid transition to higher mass-loss rates that approximates and overlaps the de Jager curve. We recommend that instead of using a linear relation or single curve, the empirical $\dot{M}$ -luminosity relation is better represented by a broad band. Interestingly, the transition to much higher $\dot{M}$ at about 105 L⊙ corresponds approximately to an initial mass of 18-20 M⊙, which is close to the upper limit for RSGs becoming Type II supernovae. * Based on observations obtained with (1) the NASA/DLR Stratospheric Observatory (SOFIA). SOFIA is jointly operated by the Universities Space Research Association, Inc. (USRA) under NASA contract NAS2-97001 and the Deutsches SOFIA Institut (DSI) under DLR contract 50OK 0901 to the University of Stuttgart, and (2) LMIRCam/LBTI on the Large Binocular Telescope (LBT), an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners include The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBTBeteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.

Keywords: Circumstellar matter, Red supergiant stars, Stellar mass loss
The Near-infrared Spectrum of the Nuclear Star Cluster: Looking below the Tip of the Iceberg, and Comparisons with Extragalactic Nuclei. Long-slit near-infrared (NIR) spectra of the Galactic nuclear star cluster (NSC) are discussed. The spectra sample the major axis of the NSC out to its half-light radius. The absorption spectrum of the central regions of the NSC is averaged over angular scales of tens of arc seconds in order to sample globular cluster-like total luminosities, and the results are compared with model spectra. The equivalent widths of Na I2.21 μm and Ca 2.26 μm outside of the center of the NSC, where light from nuclear bulge stars contributes a large fraction to the total flux, are consistent with solar chemical mixtures. In contrast, the equivalent widths of Na I2.21 μm and Ca I2.26 μm near the center of the NSC are larger than expected from models with solar chemical mixtures, even after light from the brightest evolved stars is removed. The depths of spectroscopic features changing along the major axis of the NSC are consistent with imaging studies that have found evidence of population gradients in the NSC. That Na I2.21 μm and Ca I2.26 μm are deeper than predicted for solar chemical mixtures over a range of evolutionary states is consistent with previous studies that find that the majority of stars near the center of the NSC formed from material that had nonsolar chemical mixtures. The depths of the Na I2.21 μm and Ca I2.26 μm features in the central regions of the NSC are comparable to those in the nuclear spectrum of the early-type Virgo disk galaxy NGC 4491, and are deeper than in the central spectra of NGC 253 and 7793. A spectrum of nebular emission and the youngest stars near the galactic center is also extracted. The equivalent widths of emission features in the extracted NIR spectrum are similar to those in the nuclear spectrum of NGC 253, and it is argued that this agreement is best achieved if the current episode of star formation near the center of the NSC has been in progress for at least a few megayears. * Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

Keywords: Galactic center
A Warm Jupiter Transiting an M Dwarf: A TESS Single-transit Event Confirmed with the Habitable-zone Planet Finder. We confirm the planetary nature of a warm Jupiter transiting the early M dwarf TOI-1899 using a combination of available TESS photometry; high-precision, near-infrared spectroscopy with the Habitable-zone Planet Finder; and speckle and adaptive optics imaging. The data reveal a transiting companion on an ∼29 day orbit with a mass and radius of $0.66\pm 0.07\ {M}_{{\rm{J}}}$ and ${1.15}_{-0.05}^{+0.04}\ {R}_{{\rm{J}}}$ , respectively. The star, TOI-1899, is the lowest-mass star known to host a transiting warm Jupiter, and we discuss the follow-up opportunities afforded by a warm ( ${T}_{\mathrm{eq}}\sim 362$ K) gas giant orbiting an M0 star. Our observations reveal that TOI-1899.01 is a puffy warm Jupiter, and we suggest additional transit observations to both refine the orbit and constrain the true dilution observed in TESS.

Keywords: Exoplanets
OGLE-2018-BLG-1269Lb: A Jovian Planet with a Bright I = 16 Host. We report the discovery of a planet in the microlensing event OGLE-2018-BLG-1269 with a planet-host mass ratio q ∼ 6 × 10-4, i.e., 0.6 times smaller than the Jupiter/Sun mass ratio. Combined with the Gaia parallax and proper motion, a strong one-dimensional constraint on the microlens parallax vector allows us to significantly reduce the uncertainties of lens physical parameters. A Bayesian analysis that ignores any information about light from the host yields that the planet is a cold giant $({M}_{2}={0.69}_{-0.22}^{+0.44}\,{M}_{{\rm{J}}})$ orbiting a Sun-like star $({M}_{1}={1.13}_{-0.35}^{+0.72}\,{M}_{\odot })$ at a distance of ${D}_{{\rm{L}}}={2.56}_{-0.62}^{+0.92}\,\mathrm{kpc}$ . The projected planet-host separation is ${a}_{\perp }={4.61}_{-1.17}^{+1.70}\,\mathrm{au}$ . Using Gaia astrometry, we show that the blended light lies $\lesssim 12\,\mathrm{mas}$ from the host and therefore must be either the host star or a stellar companion to the host. An isochrone analysis favors the former possibility at &gt;99.6%. The host is therefore a subgiant. For host metallicities in the range of $0.0\leqslant [\mathrm{Fe}/{\rm{H}}]\leqslant +0.3$ , the host and planet masses are then in the range of $1.16\leqslant {M}_{1}/{M}_{\odot }\leqslant 1.38$ and $0.74\leqslant {M}_{2}/{M}_{{\rm{J}}}\leqslant 0.89$ , respectively. Low host metallicities are excluded. The brightness and proximity of the lens make the event a strong candidate for spectroscopic follow-up both to test the microlensing solution and to further characterize the system.

Keywords: Gravitational microlensing, Gravitational microlensing exoplanet detection
Multiple Explanations for the Single Transit of KIC 5951458 Based on Radial Velocity Measurements Extracted with a Novel Matched-template Technique. Planetary systems that show single-transit events are a critical pathway to increasing the yield of long-period exoplanets from transit surveys. From the primary Kepler mission, KIC 5951458 b (Kepler-456b) was thought to be a single-transit giant planet with an orbital period of 1310 days. However, radial velocity (RV) observations of KIC 5951458 from the HIRES instrument on the Keck telescope suggest that the system is far more complicated. To extract precise RVs for this $V\approx 13$ star, we develop a novel matched-template technique that takes advantage of a broad library of template spectra acquired with HIRES. We validate this technique and measure its noise floor to be 4-8 m s-1 (in addition to internal RV error) for most stars that would be targeted for precision RVs. For KIC 5951458, we detect a long-term RV trend that suggests the existence of a stellar companion with an orbital period greater than a few thousand days. We also detect an additional signal in the RVs that is possibly caused by a planetary or brown dwarf companion with mass in the range of 0.6-82 MJup and orbital period below a few thousand days. Curiously, from just the data on hand, it is not possible to determine which object caused the single "transit" event. We demonstrate how a modest set of RVs allows us to update the properties of this unusual system and predict the optimal timing for future observations. ∗ 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: Exoplanet astronomy, Exoplanet detection methods, Radial velocity, Exoplanet systems