Sazuna/UAT_keywords huggingface dataset:
Long-term Stability of Planetary Systems Formed from a Transitional Disk. Transitional disks are protoplanetary disks with large and deep central holes in the gas, possibly carved by young planets. Dong &amp; Dawson simulated systems with multiple giant planets that were capable of carving and maintaining such gaps during the disk stage. Here we continue their simulations by evolving the systems for 10 Gyr after disk dissipation and compare the resulting system architecture to observed giant planet properties, such as their orbital eccentricities and resonances. We find that the simulated systems contain a disproportionately large number of circular orbits compared to observed giant exoplanets. Large eccentricities are generated in simulated systems that go unstable, but too few of our systems go unstable, likely due to our demand that they remain stable during the gas-disk stage to maintain cavities. We also explore whether transitional-disk inspired initial conditions can account for the observed younger ages of 2:1 resonant systems orbiting mature host stars. Many simulated planet pairs lock into a 2:1 resonance during the gas-disk stage, but those that are disrupted tend to be disrupted early, within the first 10 Myr. Our results suggest that systems of giant planets capable of carving and maintaining transitional disks are not the direct predecessors of observed giant planets, either because the transitional disk cavities have a different origin or another process is involved, such as convergent migration that packs planets close together at the end of the transitional disk stage.

Keywords: Protoplanetary disks, Exoplanets, Orbital resonances
Mid-IR Observations of IRAS, AKARI, WISE/NEOWISE, and Subaru for Large Icy Asteroid (704) Interamnia: A New Perspective of Regolith Properties and Water Ice Fraction. (704) Interamnia is one of the largest asteroids located in the outer main-belt region, which may contain a large amount of water ice underneath its surface. We observe this asteroid using 8.2 m Subaru telescope at mid-infrared wave bands and utilize a thermophysical model for realistic surface layers to analyze mid-infrared data from Subaru along with those of IRAS, AKARI, and Wide-field Infrared Survey Explorer (WISE)/NEOWISE. We optimize the method to convert the WISE magnitude to thermal infrared flux with temperature-dependent color corrections, which can provide significant references for main-belt asteroids at a large heliocentric distance with low surface temperature. We derive best-fitting thermal parameters of Interamnia-a mean regolith grain size of ${190}_{-180}^{+460}$ μm, with a roughness of ${0.30}_{-0.17}^{+0.35}$ and rms slope of ${27}_{-9}^{+13}$ deg, thereby producing thermal inertia ranging from 9 to 92 Jm-2 s-1/2 K-1 due to seasonal temperature variation. The geometric albedo and effective diameter are evaluated to be ${0.0472}_{-0.0031}^{+0.0033}$ and ${339}_{-11}^{+12}\,\mathrm{km}$ , respectively, being indicative of a bulk density of 1.86 ± 0.63 g cm-3. The low thermal inertia is consistent with typical B/C-type asteroids with D ≥ 100 km. The tiny regolith grain size suggests the presence of a fine regolith on the surface of Interamnia. Moreover, the seasonal and diurnal temperature distribution indicates that thermal features between the southern and northern hemispheres appear to be very different. Finally, we present an estimation of volume fraction of water ice of 9%-66% from the published grain density and porosity of carbonaceous chondrites.

Keywords: Small Solar System bodies, Main belt asteroids, Asteroids
SN 2020uem: a Possible Thermonuclear Explosion within a Dense Circumstellar Medium. I. The Nature of Type IIn/Ia-CSM SNe from Photometry and Spectroscopy. We have performed intensive follow-up observations of a Type IIn/Ia-CSM supernova (SN IIn/Ia-CSM), 2020uem, with photometry, spectroscopy, and polarimetry. In this paper, we report on the results of our observations focusing on optical/near-infrared (NIR) photometry and spectroscopy. The maximum V-band magnitude of SN 2020uem is less than -19.5 mag. The light curves decline slowly with a rate of ~0.75 mag/100 days. In the late phase (≳300 days), the light curves show accelerated decay (~1.2 mag/100 days). The optical spectra show prominent hydrogen emission lines and broad features possibly associated with Fe-peak elements. In addition, the Hα profile exhibits a narrow P-Cygni profile with an absorption minimum of ~100 km s-1. SN 2020uem shows a higher Hα/Hβ ratio (~7) than those of SNe IIn, which suggests a denser circumstellar medium (CSM). The NIR spectrum shows the Paschen and Brackett series with a continuum excess in the H and Ks bands. We conclude that the NIR excess emission originates from newly formed carbon dust. The dust mass (M d) and temperature (T d) are derived to be (M d, T d) ~ (4-7 × 10-5 M ⊙, 1500-1600 K). We discuss the differences and similarities between the observational properties of SNe IIn/Ia-CSM and those of other SNe Ia and interacting SNe. In particular, spectral features around ~4650 Å and ~5900 Å of SNe IIn/Ia-CSM are more suppressed than those of SNe Ia; these lines are possibly contributed, at least partly, by Mg I] and Na I, and may be suppressed by high ionization behind the reverse shock caused by the massive CSM.

Keywords: Light curves, Circumstellar matter, Spectroscopy, Circumstellar dust, Supernovae
SN 2020uem: a Possible Thermonuclear Explosion within a Dense Circumstellar Medium (II). The Properties of the CSM from Polarimetry and Light-curve Modeling. Type IIn/Ia-CSM supernovae (SNe IIn/Ia-CSM) are classified by their characteristic spectra, which exhibit narrow hydrogen emission lines originating from strong interaction with a circumstellar medium (CSM) together with broad lines of intermediate-mass elements. We performed intensive follow-up observations of SN IIn/Ia-CSM 2020uem, including photometry, spectroscopy, and polarimetry. In this paper, we focus on the results of polarimetry. We performed imaging polarimetry at 66 days and spectropolarimetry at 103 days after discovery. SN 2020uem shows a high continuum polarization of 1.0%-1.5% without wavelength dependence. Besides, the polarization degree and position angle keep roughly constant. These results suggest that SN 2020uem is powered by strong interaction with a confined and aspherical CSM. We performed simple polarization modeling, based on which we suggest that SN 2020uem has an equatorial-disk/torus CSM. Besides, we performed semi-analytic light-curve modeling and estimated the CSM mass. We revealed that the mass-loss rate in the final few hundred years immediately before the explosion of SN 2020uem is in the range of 0.01-0.05 M ⊙ yr-1, and that the total CSM mass is 0.5-4 M ⊙. The CSM mass can be accommodated by not only a red supergiant (RSG), but also by a red giant (RG) or an asymptotic giant branch (AGB) star. As a possible progenitor scenario of SN 2020uem, we propose a white dwarf binary system including an RG, RSG, or AGB star, especially a merger scenario via common envelope evolution, i.e., the core-degenerate scenario or a variant.

Keywords: Spectropolarimetry, Circumstellar matter, Supernovae, Polarimetry, Supernova dynamics
Superhabitability of High-obliquity and High-eccentricity Planets. Planetary obliquity and eccentricity influence climate by shaping the spatial and temporal patterns of stellar energy incident at a planet's surface, affecting both the annual mean climate and magnitude of seasonal variability. Previous work has demonstrated the importance of both planetary obliquity and eccentricity for climate and habitability, but most studies have not explicitly modeled the response of life to these parameters. While exaggerated seasons may be stressful to some types of life, a recent study found an increase in marine biological activity for moderately high obliquities &lt;45° assuming an Earth-like eccentricity. However, it is unclear how life might respond to obliquities &gt;45°, eccentricities much larger than Earth's, or the combination of both. To address this gap, we use cGENIE-PlaSim, a 3D marine biogeochemical model coupled to an atmospheric general circulation model, to investigate the response of Earth-like marine life to a large range of obliquities (0°-90°) and eccentricities (0-0.4). We find that marine biological activity increases with both increasing obliquity and eccentricity across the parameter space we considered, including the combination of high obliquity and high eccentricity. We discuss these results in the context of remote biosignatures, and we argue that planets with high obliquity and/or eccentricity may be superhabitable worlds that are particularly favorable for exoplanet life detection.

Keywords: Exoplanets, Astrobiology, Planetary climates, Biosignatures, Habitable planets
Relativistic Hybrid Stars with Sequential First-order Phase Transitions in Light of Multimessenger Constraints. In this work, we consider the properties of compact stars in which quark matter has low- and high-density phases that are separated by a first-order phase transition. Thus, unlike the commonly considered case of a single phase transition from hadronic to quark matter, our models of hybrid stars contain sequential phase transitions from hadronic matter to low- and then to high-density quark matter phases. We extend our previous study of the parameter space of hybrid stars with a single phase transition to those with sequential phase transitions, taking into account the constraints on the mass and radius of neutron stars from the NICER experiment, the experimental inferences of the neutron skin thickness of the lead nucleus by the PREX-II experiment, and constraints on the tidal deformability from the gravitational-wave event GW170817. We determine the range of the masses for which both twin and triplet configurations, i.e., identical-mass stars with two and three different values of radii, arise.

Keywords: Neutron stars, Neutron star cores, High energy astrophysics, Gravitational wave astronomy, Nuclear astrophysics
A New Stellar Mass Proxy for Subhalo Abundance Matching. Subhalo abundance matching (SHAM) has played an important role in improving our understanding of how galaxies populate their host dark matter halos. In essence, the SHAM framework is to find a dark matter halo property that best correlates with an attribute of galaxies, such as stellar mass. The peak value of the maximum circular velocity ( ${V}_{\max }$ ) a halo/subhalo has ever attained throughout its lifetime, V peak, has been a popular choice for SHAM. A recent study by Tonnesen &amp; Ostriker suggested that quantity ϕ, which combines the present-day ${V}_{\max }$ and the peak value of halo dark matter mass, performs better in predicting stellar mass than V peak. Inspired by their approach, in this work, we find that further improvement can be achieved by a quantity ψ 5 that combines the 90th percentile of ${V}_{\max }$ a halo/subhalo has ever achieved with the 60th percentile of the dark matter halo time variation rate. Tests based on the simulation TNG300 of the IllustrisTNG project show that our new SHAM scheme, with just three free parameters, can improve the stellar mass prediction and mass-dependent clustering by 15% and 18% from ϕ, respectively, over the redshift range z = 0-2.

Keywords: Galaxy dark matter halos, Galaxy formation, Galaxy physics
Cyanopolyyne Chemistry in the L1544 Prestellar Core: New Insights from GBT Observations. We report a comprehensive study of the cyanopolyyne chemistry in the prototypical prestellar core L1544. Using the 100 m Robert C. Byrd Green Bank Telescope, we observe three emission lines of HC3N, nine lines of HC5N, five lines of HC7N, and nine lines of HC9N. HC9N is detected for the first time toward the source. The high spectral resolution (~0.05 km s-1) reveals double-peak spectral line profiles with the redshifted peak a factor 3-5 brighter. Resolved maps of the core in other molecular tracers indicate that the southern region is redshifted. Therefore, the bulk of the cyanopolyyne emission is likely associated with the southern region of the core, where free carbon atoms are available to form long chains, thanks to the more efficient illumination of the interstellar field radiation. We perform a simultaneous modeling of the HC5N, HC7N, and HC9N lines to investigate the origin of the emission. To enable this analysis, we performed new calculation of the collisional coefficients. The simultaneous fitting indicates a gas kinetic temperature of 5-12 K, a source size of 80″, and a gas density larger than 100 cm-3. The HC5N:HC7N:HC9N abundance ratios measured in L1544 are about 1:6:4. We compare our observations with those toward the well-studied starless core TMC-1 and with the available measurements in different star-forming regions. The comparison suggests that a complex carbon chain chemistry is active in other sources and is related to the presence of free gaseous carbon. Finally, we discuss the possible formation and destruction routes in light of the new observations.

Keywords: Interstellar molecules, Chemical abundances, Astrochemistry, Star formation, Interstellar medium
A High-pressure Filled Ice in the H<SUB>2</SUB>O-CO<SUB>2</SUB>-CH<SUB>4</SUB> System, with Possible Consequences for the CO<SUB>2</SUB>-CH<SUB>4</SUB> Biosignature Pair. Here we constrain the speciation of carbon that may outgas in ocean exoplanets. Ocean exoplanets likely have at least a few percent by mass of water, which is sufficient to build a high-pressure ice layer between a rocky interior and the outer hydrosphere. We study the possible formation of a filled ice in the ternary system H2O-CO2-CH4. The incorporation of CH4 and CO2 in filled ice would be an important mechanism for transporting carbon across a high-pressure ice mantle into the atmosphere. The CH4-CO2 pair is also important as a potential biosignature. We find that a filled ice in the system H2O-CO2-CH4 is possible though enriched in CH4. CO2 cannot account for more than 15% by mole of the carbon content of the filled ice. Such a filled ice is less dense than an overlying ocean and would therefore discharge into the ocean, depressurize, and outgas its carbon content into the atmosphere. A high-pressure, water-rich mantle in ocean worlds may therefore support the transport of carbon from the interior into the atmosphere. More than 75% by mole of this carbon would be reduced. As long as CH4 exists/is produced in the interior and the ice mantle convects, thus transporting chemical species outward, a flux of carbon enriched in CH4 would outgas. If this persists over geological time it would negate atmospheric sinks for CH4, and explain low concentrations of atmospheric CO2. If the contrary is correct than the interior of the planet may be oxidizing.

Keywords: Biosignatures, Planetary interior, Exoplanet atmospheres
Nonlinear Fast Magnetosonic Waves in Solar Prominence Pillars. We investigate the properties of nonlinear fast magnetosonic (NFM) waves in a solar prominence, motivated by recent high-resolution and high-cadence Hinode/Solar Optical Telescope (SOT) observations of small-scale oscillations in a prominence pillar. As an example, we analyze the details of the 2012 February 14 Hinode/SOT observations of quasi-periodic propagating features consistent with NFM waves, imaged in emission in Ca II and in the far blue wing of Hα. We perform wavelet analysis and find oscillations in the 1-3 minutes period range. Guided by these observations, we model the NFM waves with a three-dimensional magnetohydrodynamics (3D MHD) model, extending previous 2.5D MHD studies. The new model includes the structure of the high-density, low-temperature material of the prominence pillar embedded in the hot corona, in both potential and non-force-free sheared magnetic field configurations. The nonlinear model demonstrates the effects of mode coupling and the propagating density compressions associated with linear and NFM waves. The guided fast magnetosonic waves, together with density compressions and currents, are reproduced in the 3D pillar structure. We demonstrate for the first time the dynamic effects of the Lorentz force due to the magnetic shear in the non-force-free field on the pillar structure and on the propagation of the waves. The insights gained from the 3D MHD modeling are useful for improving the coronal seismology of prominence structures that exhibit fast MHD wave activity.

Keywords: Active solar corona, Solar filaments, Solar prominences, Magnetohydrodynamical simulations
Early-forming Massive Stars Suppress Star Formation and Hierarchical Cluster Assembly. Feedback from massive stars plays an important role in the formation of star clusters. Whether a very massive star is born early or late in the cluster formation timeline has profound implications for the star cluster formation and assembly processes. We carry out a controlled experiment to characterize the effects of early-forming massive stars on star cluster formation. We use the star formation software suite Torch, combining self-gravitating magnetohydrodynamics, ray-tracing radiative transfer, N-body dynamics, and stellar feedback, to model four initially identical 104 M ⊙ giant molecular clouds with a Gaussian density profile peaking at 521.5 cm-3. Using the Torch software suite through the AMUSE framework, we modify three of the models, to ensure that the first star that forms is very massive (50, 70, and 100 M ⊙). Early-forming massive stars disrupt the natal gas structure, resulting in fast evacuation of the gas from the star-forming region. The star formation rate is suppressed, reducing the total mass of the stars formed. Our fiducial control model, without an early massive star, has a larger star formation rate and total efficiency by up to a factor of 3, and a higher average star formation efficiency per freefall time by up to a factor of 7. Early-forming massive stars promote the buildup of spatially separate and gravitationally unbound subclusters, while the control model forms a single massive cluster.

Keywords: Massive stars, Young massive clusters, Astronomical simulations, Star forming regions
Using Host Galaxy Photometric Redshifts to Improve Cosmological Constraints with Type Ia Supernovae in the LSST Era. We perform a rigorous cosmology analysis on simulated Type Ia supernovae (SNe Ia) and evaluate the improvement from including photometric host galaxy redshifts compared to using only the "z spec" subset with spectroscopic redshifts from the host or SN. We use the Deep Drilling Fields (~50 deg2) from the Photometric LSST Astronomical Time-Series Classification Challenge (PLAsTiCC) in combination with a low-z sample based on Data Challenge2. The analysis includes light-curve fitting to standardize the SN brightness, a high-statistics simulation to obtain a bias-corrected Hubble diagram, a statistical+systematics covariance matrix including calibration and photo-z uncertainties, and cosmology fitting with a prior from the cosmic microwave background. Compared to using the z spec subset, including events with SN+host photo-z results in (i) more precise distances for z &gt; 0.5, (ii) a Hubble diagram that extends 0.3 further in redshift, and (iii) a 50% increase in the Dark Energy Task Force figure of merit (FoM) based on the w 0 w  a CDM model. Analyzing 25 simulated data samples, the average bias on w 0 and w  a  is consistent with zero. The host photo-z systematic of 0.01 reduces FoM by only 2% because (i) most z &lt; 0.5 events are in the z spec subset, (ii) the combined SN+host photo-z has ×2 smaller bias, and (iii) the anticorrelation between fitted redshift and color self-corrects distance errors. To prepare for analyzing real data, the next SN Ia cosmology analysis with photo-zs should include non-SN Ia contamination and host galaxy misassociations.

Keywords: Type Ia supernovae
A Large-scale Kinematic Study of Molecular Gas in High-z Cluster Galaxies: Evidence for High Levels of Kinematic Asymmetry. We investigate the resolved kinematics of the molecular gas, as traced by the Atacama Large Millimeter/submillimeter Array in CO (2-1), of 25 cluster member galaxies across three different clusters at a redshift of z ~ 1.6. This is the first large-scale analysis of the molecular gas kinematics of cluster galaxies at this redshift. By separately estimating the rotation curve of the approaching and receding sides of each galaxy via kinematic modeling, we quantify the difference in total circular velocity to characterize the overall kinematic asymmetry of each galaxy. 3/14 of the galaxies in our sample that we are able to model have similar degrees of asymmetry as that observed in galaxies in the field at similar redshift based on observations of mainly ionized gas. However, this leaves 11/14 galaxies in our sample with significantly higher asymmetry, and some of these galaxies have degrees of asymmetry of up to ~50 times higher than field galaxies observed at similar redshift. Some of these extreme cases also have one-sided tail-like morphology seen in the molecular gas, supporting a scenario of tidal and/or ram pressure interaction. Such stark differences in the kinematic asymmetry in clusters versus the field suggest the evolutionary influence of dense environments, established as being a major driver of galaxy evolution at low redshift, is also active in the high-redshift universe.

Keywords: Galaxy clusters, Molecular gas, High-redshift galaxy clusters, Galactic and extragalactic astronomy, Galaxy kinematics, Radio astronomy
Long-term Quasiperiodicity in LMXB 4U 1636-536. We present the results of the low-mass X-ray binary 4U 1636-536 study. We performed a temporal analysis of all available RXTE/All-Sky Monitor, RXTE/Proportional Counter Array, Swift/Burst Alert Telescope, and MAXI data collected until the middle of 2022. Within our analysis we confirmed the previously discovered quasiperiodicity of ≃45 days present during ~2004, and we found that it continued until 2007. Moreover, we showed that similar periodicity also appeared in 2010 and 2011. At other epochs, the quasiperiodicity is only transient. We applied a time-dependent accretion disk model to the interval with the most significant X-ray quasiperiodicity. Although 4U 1636-536 is persistent, the observed quasiperiodicity can be well modeled by the hydrogen thermal-ionization instability occurring in the outer regions of the accretion disk. For our best model, the theoretical light curve's period and amplitude agree well with those observed.

Keywords: X-ray astronomy, Neutron stars, Accretion, X-ray binary stars, Stellar accretion disks, Low-mass x-ray binary stars
A Statistical Analysis of Magnetic Field Changes in the Photosphere during Solar Flares Using High-cadence Vector Magnetograms and Their Association with Flare Ribbons. We analyze high-cadence vector magnetograms (135 s) and flare-ribbon observations of 37 flares from the Solar Dynamics Observatory to understand the spatial and temporal properties of changes in the photospheric vector magnetic field and their relationship to footpoints of reconnected fields. Confirming previous studies, we find that the largest permanent changes in the horizontal field component lie near the polarity inversion line, whereas changes in the vertical field are less pronounced and are distributed throughout the active region. We find that pixels swept up by ribbons do not always exhibit permanent changes in the field. However, when they do, ribbon emission typically occurs several minutes before the start time of field changes. The changes in the properties of the field show no relation to the size of active regions, but are strongly related to the flare-ribbon properties such as ribbon magnetic flux and ribbon area. For the first time, we find that the duration of permanent changes in the field is strongly coupled with the duration of the flare, lasting on average 29% of the duration of the GOES flare. Our results suggest that changes in photospheric magnetic fields are caused by a combination of two scenarios: contraction of flare loops driven by magnetic reconnection and coronal implosion.

Keywords: The Sun, Solar flares, Solar magnetic fields