Sazuna/UAT_keywords huggingface dataset:
Zwicky Transient Facility and Globular Clusters: Calibration of the gr-band Absolute Magnitudes for the Yellow Post-asymptotic-giant-branch Stars. We present the first absolute calibration for the yellow post-asymptotic-giant-branch (PAGB) stars in the g and r band based on time-series observations from the Zwicky Transient Facility. These absolute magnitudes were calibrated using four yellow PAGB stars (one nonvarying star and three Type II Cepheids) located in the globular clusters. We provide two calibrations of the gr-band absolute magnitudes for the yellow PAGB stars, by using an arithmetic mean and a linear regression. We demonstrate that the linear regression provides a better fit to the g-band absolute magnitudes for the yellow PAGB stars. These calibrated gr-band absolute magnitudes have a potential to be used as Population II distance indicators in the era of time-domain synoptic sky surveys.

Keywords: Globular star clusters, Post-asymptotic giant branch stars, Sky surveys, Wide-field telescopes, Distance indicators
Implications for the Collisional Strength of Jupiter Trojans from the Eurybates Family. In this work, we model the collisional evolution of the Jupiter Trojans and determine under which conditions the Eurybates-Queta system survives. We show that the collisional strength of the Jupiter Trojans and the age of the Eurybates family and by extension Queta are correlated. The collisional grinding of the Jupiter Trojan population over 4.5 Gy results in a size-frequency distribution (SFD) that remains largely unaltered at large sizes (&gt;10 km) but is depleted at small sizes (10 m to 1 km). This results in a turnover in the SFD, the location of which depends on the collisional strength of the material. It is to be expected that the Trojan SFD bends between 1 and 10 km. Based on the SFD of the Eurybates family, we find that the family was likely the result of a catastrophic impact onto a 100 km rubble pile target. This corresponds to objects with a rather low collisional strength (10 times weaker than that of basaltic material studied in Benz &amp; Asphaug). Assuming this weak strength, and an initial cumulative slope of the size-frequency distribution of 2.1 between diameters of 2 m and 100 km when the Trojans were captured, the existence of Queta, the satellite of Eurybates, implies an upper limit for the family age of 3.7 Gy. Alternatively, we demonstrate that an unconventional collisional strength with a minimum at 20 m is a plausible candidate to ensure the survival of Queta over the age of the solar system. Finally, we show how different collisional histories change the expected number of craters on the targets of the Lucy mission and that Lucy will be able to differentiate between them.

Keywords: Collisional processes, Theoretical models, Asteroids, Jupiter trojans, Trojan asteroids
A Deep and Wide Twilight Survey for Asteroids Interior to Earth and Venus. We are conducting a survey using twilight time on the Dark Energy Camera with the Blanco 4 m telescope in Chile to look for objects interior to Earth's and Venus' orbits. To date we have discovered two rare Atira/Apohele asteroids, 2021 LJ4 and 2021 PH27, which have orbits completely interior to Earth's orbit. We also discovered one new Apollo-type Near Earth Object (NEO) that crosses Earth's orbit, 2022 AP7. Two of the discoveries have diameters ≳1 km. 2022 AP7 is likely the largest Potentially Hazardous Asteroid (PHA) discovered in about eight years. To date we have covered 624 square degrees of sky near to and interior to the orbit of Venus. The average images go to 21.3 mag in the r band, with the best images near 22nd mag. Our new discovery 2021 PH27 has the smallest semimajor axis known for an asteroid, 0.4617 au, and the largest general relativistic effects (53 arcsec/century) known for any body in the solar system. The survey has detected ~15% of all known Atira NEOs. We put strong constraints on any stable population of Venus co-orbital resonance objects existing, as well as the Atira and Vatira asteroid classes. These interior asteroid populations are important to complete the census of asteroids near Earth, including some of the most likely Earth impactors that cannot easily be discovered in other surveys. Comparing the actual population of asteroids found interior to Earth and Venus with those predicted to exist by extrapolating from the known population exterior to Earth is important to better understand the origin, composition, and structure of the NEO population.

Keywords: Near-Earth objects, Earth trojans, Small Solar System bodies, Atira group, Asteroids, Aten group, Apollo group
SKYSURF: Constraints on Zodiacal Light and Extragalactic Background Light through Panchromatic HST All-sky Surface-brightness Measurements: II. First Limits on Diffuse Light at 1.25, 1.4, and 1.6 μm. We present the first results from the HST Archival Legacy project "SKYSURF." As described in Windhorst et al., SKYSURF utilizes the large HST archive to study the diffuse UV, optical, and near-IR backgrounds and foregrounds in detail. Here, we utilize SKYSURF's first sky-surface-brightness measurements to constrain the level of near-IR diffuse Extragalactic Background Light (EBL) in three near-IR filters (F125W, F140W, and F160W). This is done by comparing our preliminary sky measurements of &gt;30,000 images to zodiacal light models, carefully selecting the darkest images to avoid contamination from stray light. Our sky-surface-brightness measurements have been verified to an accuracy of better than 1%, which when combined with systematic errors associated with HST, results in sky-brightness uncertainties of ~ 2%-4% ≃ 0.005 MJy sr-1 in each image. When compared to the Kelsall et al. zodiacal model, an isotropic diffuse background of ~30 nW m-2 sr-1 remains, whereas using the Wright zodiacal model results in no discernible diffuse background. Based primarily on uncertainties in the foreground model subtraction, we present limits on the amount of diffuse EBL of 29, 40, and 29 nW m-2 sr-1, for F125W, F140W, and F160W, respectively. While this light is generally isotropic, our modeling at this point does not distinguish between a cosmological origin or a solar system origin (such as a dim, diffuse, spherical cloud of cometary dust).

Keywords: Zodiacal cloud, Star counts, Cosmic background radiation, Galaxy counts
A Comprehensive Study of Five Intermediate-age Pismis (2, 3, 7, 12, 15) Clusters Using Photometric and Astrometric Data from Gaia EDR3. Open clusters are groups of stars that form simultaneously; hence, these are excellent probes to test theories of star formation, stellar evolution, and dynamics in the Milky Way disk. We carry out a detailed photometric and kinematic study of five poorly studied intermediate-age open clusters, Pismis 2 (Pi 2), Pismis 3 (Pi 3), Pismis 7 (Pi 7), Pismis 12 (Pi 12), and Pismis 15 (Pi 15), using the Gaia EDR3 database. By estimating the membership probabilities of stars, we recognized 635, 1488, 535, 368, and 494 most probable members for these clusters by using proper-motion and parallax data taken from Gaia EDR3. The radial density profiles of cluster members provide cluster radii of 4.'5-6.'5 for these clusters. Their ages range from 0.9 to 2.5 Gyr, and distances range, using parallax, from 2.15 to 5.10 kpc. The overall mass function slopes for main-sequence stars are found as 0.27 ± 0.16 (for 1.0-1.6 M ⊙ stars), 0.86 ± 0.27 (for 1.0-2.1 M ⊙ stars), 1.08 ± 0.32 (for 1.0-2.2 M ⊙ stars), 0.89 ± 0.38 (for 1.0-2.2 M ⊙ stars), and 1.07 ± 0.28 (for 1.0-2.1 M ⊙ stars) for clusters Pi 2, Pi 3, Pi 7, Pi 12, and Pi 15. Our obtained values of slopes are flatter in comparison with Salpeter's value (x = 1.35) within uncertainty. The present study demonstrates that all these Pismis clusters are dynamically relaxed. We found that these objects follow a circular path around the Galactic center. We compute these clusters' apex coordinates (A, D) and other kinematic parameters.

Keywords: Initial mass function, Stellar kinematics, Orbits, Stellar dynamics, Proper motions, Open star clusters
The K2-3 System Revisited: Testing Photoevaporation and Core-powered Mass Loss with Three Small Planets Spanning the Radius Valley. Multiplanet systems orbiting M dwarfs provide valuable tests of theories of small-planet formation and evolution. K2-3 is an early M dwarf hosting three small exoplanets (1.5-2.0 R ⊕) at distances of 0.07-0.20 au. We measure the high-energy spectrum of K2-3 with HST/COS and XMM-Newton and use empirically driven estimates of Lyα and extreme-ultraviolet flux. We use EXOFASTv2 to jointly fit radial velocity, transit, and spectral energy distribution data. This constrains the K2-3 planet radii to 4% uncertainty and the masses of K2-3b and c to 13% and 30%, respectively; K2-3d is not detected in radial velocity measurements. K2-3b and c are consistent with rocky cores surrounded by solar composition envelopes (mass fractions of ${0.36}_{-0.11}^{+0.14} \% $ and ${0.07}_{-0.05}^{+0.09} \% $ ), H2O envelopes ( ${55}_{-12}^{+14} \% $ and ${16}_{-10}^{+17} \% $ ), or a mixture of both. However, based on the high-energy output and estimated age of K2-3, it is unlikely that K2-3b and c retain solar composition atmospheres. We pass the planet parameters and high-energy stellar spectrum to atmospheric models. Dialing the high-energy spectrum up and down by a factor of 10 produces significant changes in trace molecule abundances, but not at a level detectable with transmission spectroscopy. Though the K2-3 planets span the small-planet radius valley, the observed system architecture cannot be readily explained by photoevaporation or core-powered mass loss. We instead propose that (1) the K2-3 planets are all volatile-rich, with K2-3d having a lower density than typical of super-Earths, and/or (2) the K2-3 planet architecture results from stochastic processes such as planet formation, planet migration, and impact erosion.

Keywords: M dwarf stars, Exoplanet atmospheric composition , X-ray astronomy, Hubble Space Telescope, Exoplanet systems, Ultraviolet astronomy, Exoplanet evolution, Low mass stars
Detection of Na and K in the Atmosphere of the Hot Jupiter HAT-P-1b with P200/DBSP. We present a new optical transmission spectrum of the hot Jupiter HAT-P-1b based on two transits observed with the Double Spectrograph (DBSP) on the Palomar 200-inch (P200) telescope. The DBSP transmission spectrum, covering a wavelength range from 3250 to 10007 Å, is consistent with that observed with the Hubble Space Telescope (HST), but the former has a finer spectral resolution. The DBSP spectrum alone reveals the presence of a pressure-broadened line wing for Na, the line cores for both Na and K, and tentative evidence for H2O. We obtain consistent results from the spectral retrieval analyses performed on the DBSP-only data set and the DBSP, HST, and Spitzer combined data set. Our retrievals suggest a mostly clear atmosphere for HAT-P-1b, with a cloud coverage of ${22}_{-3}^{+5}$ % that is dominated by enhanced haze. We derive subsolar abundances for Na, K, and C, and subsolar to solar for O. Future observations with James Webb Space Telescope and ground-based high-resolution spectrographs should be able to not only confirm the presence of these species but also stringently constrain the formation and migration pathways for HAT-P-1b.

Keywords: Exoplanet atmospheric composition , Exoplanets, Hot Jupiters, Transmission spectroscopy, Exoplanet atmospheres
The Solar Neighborhood L: Spectroscopic Discovery of K Dwarfs Younger Than 1 Gyr and New Binaries within 30 pc. As part of a comprehensive effort to characterize the nearest stars, the CHIRON echelle spectrograph on the CTIO/SMARTS 1.5 m telescope is being used to acquire high-resolution (R = 80,000) spectra of K dwarfs within 50 pc. This paper provides spectral details about 35 K dwarfs from five benchmark sets with estimated ages spanning 20 Myr-5.7 Gyr. Four spectral age and activity indicators are tested, three of which aligned with the estimated ages of the benchmark groups-the Na I doublet (5889.95 and 5895.92 Å), the Hα line (6562.8 Å), and the Li I resonance line (6707.8 Å). The benchmark stars are then used to evaluate seven field K dwarfs exhibiting variable radial velocities for which initial CHIRON data did not show obvious companions. Two of these stars are estimated to be younger than 700 Myr, while one exhibits stellar activity unusual for older K-dwarf field stars and is possibly young. The four remaining stars turn out to be spectroscopic binaries, two of which are being reported here for the first time with orbital periods found using CHIRON data. Spectral analysis of the combined sample of 42 benchmark and variable radial velocity stars indicates temperatures ranging from 3900 to 5300 K and metallicities from -0.4 &lt; [Fe/H] &lt; +0.2. We also determine $\mathrm{log}g=4.5\mbox{--}4.7$ for main-sequence K dwarfs. Ultimately, this study will target several thousand of the nearest K dwarfs and provide results that will serve present and future studies of stellar astrophysics and exoplanet habitability.

Keywords: Stellar ages, Stellar properties, Solar neighborhood, Stellar activity, Spectroscopy, K dwarf stars, Late-type dwarf stars, Stellar associations
Evolution of the Hub-filament Structures in IC 5146 in the Context of the Energy Balance of Gravity, Turbulence, and Magnetic Field. We present the results of 850 μm polarization and C18O (3 - 2) line observations toward the western hub-filament structure (W-HFS) of the dark Streamer in IC 5146 using the James Clerk Maxwell Telescope SCUBA-2/POL-2 and HARP instruments. We aim to investigate how the relative importance of the magnetic field, gravity, and turbulence affects core formation in HFS by comparing the energy budget of this region. We identified four 850 μm cores and estimated the magnetic field strengths (B pos) of the cores and the hub and filament using the Davis-Chandrasekhar-Fermi method. The estimated B pos is ~80 to 1200 μG. From Wang et al., B pos of E-47, a core in the eastern hub (E-hub), and E-hub were reestimated to be 500 and 320 μG, respectively, with the same method. We measured the gravitational (E G), kinematic (E K), and magnetic energies (E B) in the filament and hubs and compared the relative importance among them. We found that an E B-dominant filament has aligned fragmentation type, while E G-dominant hubs show no and clustered fragmentation types. In the E G dominant hubs, it seems that the portion of E K determines whether the hub becomes to have clustered (the portion of E K ~ 20%) or no fragmentation type (~10%). We propose an evolutionary scenario for the E- and W-HFSs, where the HFS forms first by the collision of turbulent flows, and then the hubs and filaments can go into various types of fragmentation depending on their energy balance of gravity, turbulence, and magnetic field.

Keywords: Star forming regions, Interstellar magnetic fields, Interstellar medium, Submillimeter astronomy, Polarimetry
MIRECLE: Science Yield for a Mid-infrared Explorer-class Mission to Study Nontransiting Rocky Planets Orbiting the Nearest M Stars Using Planetary Infrared Excess. Recent investigations have demonstrated the potential for utilizing a new observational and data-analysis technique for studying the atmospheres of nontransiting exoplanets with combined light that relies on acquiring simultaneous, broad-wavelength spectra and resolving planetary infrared emission from the stellar spectrum through simultaneous fitting of the stellar and planetary spectral signatures. This new data-analysis technique, called planetary infrared excess (PIE), holds the potential to open up the opportunity for measuring mid-infrared (MIR) phase curves of nontransiting rocky planets around the nearest stars with a relatively modest telescope aperture. We present simulations of the performance and science yield for a mission and instrument concept that we call the MIR Exoplanet CLimate Explorer, a concept for a moderately sized cryogenic telescope with broad wavelength coverage (1-18 μm) and a low-resolution (R ~ 50) spectrograph designed for the simultaneous wavelength coverage and extreme flux measurement precision necessary to detect the emission from cool rocky planets with PIE. We present exploratory simulations of the potential science yield for PIE measurements of the nearby planet Proxima Centauri b, showing the potential to measure the composition and structure of an Earth-like atmosphere with a relatively modest observing time. We also present overall science yields for several mission architecture and performance metrics, and discuss the technical performance requirements and potential telescope and instrument technologies that could meet these requirements.

Keywords: Extrasolar rocky planets, Exoplanets, Exoplanet astronomy, Space observatories, Exoplanet atmospheres
Extremely Inclined Orbit of the S-type Planet γ Cep Ab Induced by the Eccentric Kozai-Lidov Mechanism. γ Cep Ab is a typical S-type planet, which occupies a nearly perpendicular planetary orbit relative to the binary. Here, we use a Markov Chain Monte Carlo sampler to conduct a full N-body fitting and derive self-consistent orbital solutions for this hierarchical system. We then employ the eccentric Kozai-Lidov (EKL) mechanism to explain the extremely inclined orbit of the S-type planet γ Cep Ab. The EKL mechanism plays an essential part in our exploration of the significant oscillations of the mutual inclination i mut between the planet and the secondary star. We perform a qualitative analysis and use extensive numerical integrations to investigate the flip conditions and timescales of γ Cep Ab's orbit. When the planetary mass is 15 M Jup, the planet can reach i mut ~ 113° given the critical initial conditions of i mut &lt; 60° and e 1 &lt; 0.7. The timescale for the first orbital flip decreases with the increase of the perturbation Hamiltonian. The flipping orbits of γ Cep Ab are confirmed to have a large possibility of remaining stable, based on surfaces of section and the secular stability criterion. Furthermore, we extend the application of EKL to general S-type planetary systems with a 1/a 2 ≤ 0.1, where the most intense excitation of i mut occurs when a 1/a 2 = 0.1 and e 2 ~ 0.8, and the variation in planetary mass mainly affects the flip possibility where e 1 ≤ 0.3.

Keywords: Exoplanet dynamics
Utilizing a Global Network of Telescopes to Update the Ephemeris for the Highly Eccentric Planet HD 80606 b and to Ensure the Efficient Scheduling of JWST. The transiting planet HD 80606 b undergoes a 1000 fold increase in insolation during its 111 days orbit due to it being highly eccentric (e = 0.93). The planet's effective temperature increases from 400 to over 1400 K in a few hours as it makes a rapid passage to within 0.03 au of its host star during periapsis. Spectroscopic observations during the eclipse (which is conveniently oriented a few hours before periapsis) of HD 80606 b with the James Webb Space Telescope (JWST) are poised to exploit this highly variable environment to study a wide variety of atmospheric properties, including composition, chemical and dynamical timescales, and large scale atmospheric motions. Critical to planning and interpreting these observations is an accurate knowledge of the planet's orbit. We report on observations of two full-transit events: 2020 February 7 as observed by the TESS spacecraft and 2021 December 7-8 as observed with a worldwide network of small telescopes. We also report new radial velocity observations which, when analyzed with a coupled model to the transits, greatly improves the planet's orbital ephemeris. Our new orbit solution reduces the uncertainty in the transit and eclipse timing of the JWST era from tens of minutes to a few minutes. When combined with the planned JWST observations, this new precision may be adequate to look for non-Keplerian effects in the orbit of HD 80606 b.

Keywords: Observational astronomy, Orbit determination, Exoplanets
celmech: A Python Package for Celestial Mechanics. We present celmech, an open-source Python package designed to facilitate a wide variety of celestial mechanics calculations. The package allows users to formulate and integrate equations of motion incorporating user-specified terms from the classical disturbing function expansion of the interaction potential between pairs of planets. The code can be applied, for example, to isolate the contribution of particular resonances to a system's dynamical evolution and develop simple analytical models with the minimum number of terms required to capture a particular dynamical phenomenon. Equations and expressions can be easily manipulated by leveraging the extensive symbolic mathematics capabilities of the sympy Python package. The celmech package is designed to interface seamlessly with the popular N-body code REBOUND to facilitate comparisons between calculation results and direct N-body integrations. The code is extensively documented, and numerous example Jupyter notebooks illustrating its use are available online.

Keywords: Celestial mechanics, Computational methods, Perturbation methods
Mass Production of 2021 KMTNet Microlensing Planets. I. We inaugurate a program of "mass production" of microlensing planets discovered in 2021 KMTNet data, with the aim of laying the basis for future statistical studies. While we ultimately plan to quickly publish all 2021 planets meeting some minimal criteria, the current sample of four was chosen simply on the basis of having low initial estimates of the planet-host mass ratio, q. It is therefore notable that two members of this sample suffer from a degeneracy in the normalized source radius ρ that arises from different morphologies of closely spaced caustics. All four planets (KMT-2021-BLG-1391, KMT-2021-BLG-1253, KMT-2021-BLG-1372, KMT-2021-BLG-0748) have well-characterized mass ratios, q, and therefore are suitable for mass-ratio frequency studies. Both of the ρ degeneracies can be resolved by future adaptive optics (AO) observations on 30 m class telescopes. We provide general guidance for such AO observations for all events in anticipation of the prospect that they will revolutionize the field of microlensing planets.

Keywords: Gravitational microlensing
Carbon Abundance of Stars in the LAMOST-Kepler Field. The correlation between host star iron abundance and the exoplanet occurrence rate is well established and arrived at in several studies. Similar correlations may be present for the most abundant elements, such as carbon and oxygen, which also control the dust chemistry of the protoplanetary disk. In this paper, using a large number of stars in the Kepler field observed by the LAMOST survey, it has been possible to estimate the planet occurrence rate with respect to the host star carbon abundance. Carbon abundances are derived using synthetic spectra fit of the CH- G-band region in the LAMOST spectra. The carbon abundance trend with metallicity is consistent with the previous studies and follows the Galactic chemical evolution (GCE). Similar to [Fe/H], we find that the [C/H] values are higher among giant-planet hosts. The trend between [C/Fe] and [Fe/H] in planet hosts and single stars is similar; however, there is a preference for giant planets around host stars with a subsolar [C/Fe] ratio and higher [Fe/H]. Higher metallicity and subsolar [C/Fe] values are found among younger stars as a result of GCE. Hence, based on the current sample, it is difficult to interpret the results as a consequence of GCE or due to planet formation.

Keywords: Exoplanet catalogs, Surveys, Stellar abundances, Spectroscopy, Planet hosting stars, Exoplanet formation