Sazuna/UAT_keywords huggingface dataset:
Tidally Distorted Barytropes and Their Roche Limits, with Application to WASP-12b. The hot Jupiter WASP-12b has been found to be on a decaying 1.09 day orbit. The mean density of the planet inferred from transit and radial-velocity data is near its Roche limit; just how near depends on the planet's uncertain internal structure. There is also spectroscopic evidence of mass loss. We accurately calculate the Roche density on the assumption of a synchronously rotating n = 1 polytrope, and find this to be only 15%-20% below the observational estimates for the mean density. We discuss the implied shape of the planet, its lifetime before complete disruption, and its current rate of mass loss based on our improved tidal model. The present mass-loss rate is at least as sensitive to the opacity and temperature profiles of the planet's atmosphere as to its internal structure, however.

Keywords: Exoplanet astronomy, Hot Jupiters, Tidal distortion, Exoplanets
Polarized Emission from Four Supernova Remnants in the THOR Survey. We present polarization and Faraday rotation for the supernova remnants (SNRs) G46.8 - 0.3, G43.3 - 0.2, G41.1 - 0.3, and G39.2 - 0.3 in the L-band (1-2 GHz) radio continuum in the H I/OH/Recombination line survey. We detect polarization from G46.8 - 0.3, G43.3 - 0.2, and G39.2 - 0.3 but find upper limits at the 1% level of Stokes I for G41.1 - 0.3. For G46.8 - 0.3 and G39.2 - 0.3, the fractional polarization varies on small scales from 1% to ~6%. G43.3 - 0.2 is less polarized with fractional polarization ≲3%. We find upper limits at the 1% level for the brighter regions in each SNR with no evidence for associated enhanced Faraday depolarization. We observe significant variation in Faraday depth and fractional polarization on angular scales down to the resolution limit of 16″. Approximately 6% of our polarization detections from G46.8 - 0.3 and G39.2 - 0.3 exhibit two-component Faraday rotation and 14% of polarization detections in G43.3 - 0.2 are multicomponent. For G39.2 - 0.3, we find a bimodal Faraday depth distribution with a narrow peak and a broad peak for all polarization detections as well as for the subset with two-component Faraday rotation. We identify the narrow peak with the front side of the SNR and the broad peak with the back side. Similarly, we interpret the observed Faraday depth distribution of G46.8 - 0.3 as a superposition of the distributions from the front side and the back side. We interpret our results as evidence for a partially filled shell with small-scale magnetic field structure and internal Faraday rotation.

Keywords: Surveys, Supernova remnants, Interstellar magnetic fields, Radio continuum emission, Polarimetry
Computational Estimation of the Binding Energies of PO<SUB> x </SUB> and HPO<SUB> x </SUB> (x = 2, 3) Species. The distribution of molecules between the gas and solid phase during star and planet formation determines the trajectory of gas and grain surface chemistry, as well as the delivery of elements to nascent planets. This distribution is primarily set by the binding energies of different molecules to water ice surfaces. We computationally estimated the binding energies of 10 astrochemically relevant P-bearing species on water surfaces. We also validate our method for 20 species with known binding energies. We used Density Functional Theory (DFT) calculations (M06-2X/aug-cc-pVDZ) to calculate the energetics of molecules and water-molecule clusters (1-3 H2O molecules) and from this determined the binding energy by comparing the complex and the separate molecule and cluster energies. We also explore whether these estimates can be improved by first calibrating our computational method using experimentally measured binding energies. Using the 20 reference molecules we find that the 2H2O cluster size yields the best binding energy estimates and that the application of a calibration to the data may improve the results for some classes of molecules, including more-refractory species. Based on these calculations we find that small P-bearing molecules such as PH3, PN, PO, HPO, PO2, and POOH are relatively volatile and should desorb prior or concomitantly with water ice, while H2PO, HPO2, PO3, and PO2OH can strongly bind to any hydroxylated surface and will likely remain on the interstellar grains surface past the desorption of water ice. The depletion of P carriers on grains constitutes a pathway for the inclusion of phosphorous molecules in planets and planetesimals.

Keywords: Interstellar molecules, Interstellar abundances, Theoretical models, Astrochemistry
New Coronae and Stellar Associations Revealed by a Clustering Analysis of the Solar Neighborhood. We present the results of a density-based clustering analysis of the 6D XYZ Galactic positions and UVW-space velocities of nearby (≤200 pc) Gaia Early Data Release 3 stars with radial velocities using HDBSCAN, in opposition to previous studies (Kounkel &amp; Covey 2019; Meingast et al. 2021) that only included positions and tangential velocities. Among the 241 recovered clusters, we identify more than 50 known associations, 32 new candidate stellar streams aged 100 Myr to 3 Gyr, nine extensions of known Theia groups uncovered by Kounkel &amp; Covey, and eight newly recognized coronae around nearby open clusters. Three confirmed exoplanet-hosting stars and three more TESS transiting exoplanet candidates are part of the new groups discovered here, including TOI-1807 and TOI-2076 from Hedges et al. (2021) that were suspected to belong to a yet unidentified moving group. The new groups presented here were not previously recognized because of their older ages, low spatial density, and projection effects that spread out the tangential velocities of their nearby comoving members. Several newly identified structures reach distances within 60 pc of the Sun, providing new grounds for the identification of isolated planetary-mass objects. The nearest member of the newly recognized corona of Volans-Carina is V419 Hya, a known young debris disk star at a distance of 22 pc. This study outlines the importance of further characterization of young associations in the immediate solar neighborhood, which will provide new laboratories for the precise age calibration of nearby stars, exoplanets, and substellar objects.

Keywords: Stellar kinematics, Open star clusters, Clustering, Stellar associations
Transverse Vector Decomposition Method for Analytical Inversion of Exoplanet Transit Spectra. We develop a new method for analytical inversion of binned exoplanet transit spectra and for retrieval of planet parameters. The method has a geometrical interpretation and treats each observed spectrum as a single vector $\overrightarrow{r}$ in the multidimensional spectral space of observed bin values. We decompose the observed $\overrightarrow{r}$ into two orthogonal components: a wavelength-independent component ${\overrightarrow{r}}_{\parallel }$ corresponding to the spectral mean across all observed bins, and a transverse component ${\overrightarrow{r}}_{\perp }$ that is wavelength dependent and contains the relevant information about the atmospheric chemistry. The method allows us to extract, without any prior assumptions or additional information, the relative mass (or volume) mixing ratios of the absorbers in the atmosphere, the scale height to stellar radius ratio, H/R  S , and the atmospheric temperature. The method is illustrated and validated with several examples of increasing complexity.

Keywords: Exoplanet atmospheric composition , Transits, Transmission spectroscopy, Analytical mathematics, Radiative transfer, Exoplanet atmospheres
A Maximum Likelihood Calibration of the Tip of the Red Giant Branch Luminosity from High Latitude Field Giants Using Gaia Early Data Release 3 Parallaxes. The calibration of the tip of the red giant branch (TRGB) in the I band has a direct role in determinations of the Hubble constant, a subject of recent interest due to the discrepancy between direct and indirect estimates of its value. We present a maximum likelihood method designed to obtain an independent calibration of the brightness of TRGB using Gaia parallaxes from the Early Data Release 3 (EDR3) of Milky Way field giants at high Galactic latitude. We adopt simple parameterizations for the Milky Way stellar luminosity function and density law and optimize the likelihood of the observed sample as a function of those parameters. Using parameters to partially constrain the luminosity function from other galaxies similar to the Milky Way for which high-quality TRGB data are available, we find values of the TRGB magnitude of  MITRGB=‑3.91±0.05  (stat) ± 0.09 (sys) mag, where the systematic uncertainty covers the range of shape parameters found in our Milky Way sample and in reference galaxies. While APASS Data Release 9 all-sky photometry is insufficient to provide a reliable constraint on the shape of the Milky Way luminosity function, we estimate that the photometry from Gaia Data Release 3 (mid-2022) will allow better constraints on the shape, and lower statistical uncertainties on the tip by a factor of 3. With the expected releases of improved parallax measurements from Gaia, the method of calibrating the TRGB luminosity from field giants is expected to reach ∼0.01 mag uncertainty, which is an important step toward a precise TRGB-based determination of the Hubble constant.

Keywords: Red giant tip, Parallax, Field stars, Distance indicators, Hubble constant, Calibration, Absolute magnitude, Maximum likelihood estimation, Milky Way Galaxy
Mergers of Supermassive and Intermediate-mass Black Holes in Galactic Nuclei from Disruptions of Star Clusters. Gravitational waves (GWs) offer an unprecedented opportunity to survey the sky and detect mergers of compact objects. While intermediate-mass black holes (IMBHs) have not been detected beyond any reasonable doubt with either dynamical or accretion signatures, the GW landscape appears very promising. Mergers of an IMBH with a supermassive black hole (SMBH) will be primary sources for the planned space-based mission LISA and could be observed up to the distant universe. SMBH-IMBH binaries can be formed as a result of the migration and merger of stellar clusters at the center of galaxies, where an SMBH lurks. We build for the first time a semianalytical framework to model this scenario and find that the comoving merger rate of SMBH-IMBH binaries is ~10-4 Gpc-3 yr-1 in the local universe for a unity IMBH occupation fraction, scales linearly with it, and has a peak at z ≈ 0.5-2. Our model predicts ~0.1 events yr-1 within redshift z ≈ 3.5 if 10% of the inspiraled star clusters hosted an IMBH, while ~1 event yr-1 for a unity occupation fraction. More than 90% of these systems will be detectable with LISA with a signal-to-noise ratio larger than 10, promising to potentially find a family of IMBHs.

Keywords: Globular star clusters, Supermassive black holes, Intermediate-mass black holes, Gravitational waves, Astrophysical black holes
Sun-as-a-star Analyses of Various Solar Active Events Using Hα Spectral Images Taken by SMART/SDDI. Sun-as-a-star analyses in which observational data is spatially integrated are useful for interpreting stellar data. For future applications to stellar observations, we performed Sun-as-a-star analyses of Hα spectra for various active events on the Sun, not only for flares and filament eruptions/surges on the solar disk, but also for eruptions of off-limb prominences using Hα spectral images taken by the Solar Magnetic Activity Research Telescope/Solar Dynamics Doppler Imager at Hida Observatory, Kyoto University. All the analyzed events show emission relative to the pre-event state and the changes in their Hα equivalent widths are all on the orders of 10-4 Å. Sun-as-a-star Hα spectra exhibit different features depending on the causes of the emission: (i) flares show emission at the Hα line center, together with red asymmetry and line broadening, as reported in a previous study, (ii) filament eruptions with and without flares show emission near the Hα line center, accompanied by blueshifted/redshifted absorption; notably, the disappearance of dark filaments leads to the apparent enhancement of the Hα line center emission, and (iii) eruptions of off-limb prominences show blueshifted/redshifted emission. These spectral features enable us to identify the active phenomena on Sun-like stars. We have also found that even the filament eruptions showing redshifted absorptions in Sun-as-a-star Hα spectra lead to coronal mass ejections (CMEs). This result suggests that even if the falling components of stellar filament eruptions are detected as redshifted absorptions in Hα spectra, such stellar filament eruptions may also develop into CMEs.

Keywords: Solar flares, Solar prominences, Stellar coronal mass ejections, Solar coronal mass ejections, Stellar flares, Solar filament eruptions, Solar chromosphere
Extended Cosmic Ray Decreases with Strong Anisotropy after Passage of Interplanetary Shocks. The passage of an interplanetary shock and/or interplanetary coronal mass ejection often causes a rapid decrease in the Galactic cosmic-ray (GCR) flux, known as a Forbush decrease, followed by a recovery of the flux over some days. These local effects are of short duration and strongly rigidity dependent, with higher-rigidity particles exhibiting much weaker effects. In contrast, we present data for two events in which the cosmic-ray flux gradually decreased for about 1 week after shock passage, then recovering over the following week, with the highest anisotropy levels observed throughout Solar Cycle 24. These extended decreases have a weak rigidity dependence and are much more prominent in observations at higher cutoff rigidity, where the initial Forbush decrease is not clearly detected and other variations are generally weak, as we demonstrate using data from the Princess Sirindhorn Neutron Monitor at Doi Inthanon, Thailand with a cutoff rigidity of about 17 GV. We propose that these extended decrease events were initiated upon the passage of an interplanetary shock that inhibited the inflow of GCRs along the interplanetary magnetic field, possibly due to magnetic mirroring at the shock. We also discuss the general behavior of GCR anisotropy as observed at this high cutoff rigidity.

Keywords: Galactic cosmic rays, Solar-terrestrial interactions, Forbush effect, Interplanetary shocks
Collisional Growth Efficiency of Dust Aggregates and Its Independence of the Strength of Interparticle Rolling Friction. The pairwise collisional growth of dust aggregates consisting of submicron-sized grains is the first step of planet formation, and understanding the collisional behavior of dust aggregates is therefore essential. It is known that the main energy dissipation mechanisms are the tangential frictions between particles in contact, namely, rolling, sliding, and twisting. However, there is great uncertainty for the strength of rolling friction, and the dependence of the collisional growth condition on the strength of rolling friction was poorly understood. Here we performed numerical simulations of collisions between two equal-mass porous aggregates with various collision velocities and impact parameters, and we also changed the strength of rolling friction systematically. We found that the threshold of the collision velocity for the fragmentation of dust aggregates is nearly independent of the strength of rolling friction. This is because the total amount of the energy dissipation by the tangential frictions is nearly constant even though the strength of rolling friction is varied.

Keywords: Planetesimals, Protoplanetary disks, Planet formation, Circumstellar disks
Ultra-diffuse Galaxies as Extreme Star-forming Environments. II. Star Formation and Pressure Balance in H I-rich UDGs. In addition to occupying the extreme, diffuse tail of the dwarf galaxy population, ultra-diffuse galaxies (UDGs) are themselves a key laboratory in which to study star formation in extreme low-density environments. In the second paper of this series, we compare the spatially resolved star formation activity of 22 H I-selected UDGs and 21 "normal" dwarf galaxies within 120 Mpc to predictions within the pressure-regulated, feedback-modulated (PRFM) theory of star formation. To do so, we employ a joint spectral energy distribution fitting method that allows us to estimate star formation rate and stellar mass surface density from UV-optical imaging. We find that the PRFM framework extends successfully to the UDG regime-although the UDGs in our sample show unusually low star formation rate surface densities given their H I content, this low star formation efficiency can be naturally explained by the diffuse structure of the UDGs. In fact, when cast in the PRFM framework, the relationship between midplane pressure and star formation in the UDG sample is in good agreement not only with the "normal" dwarf reference sample, but also with measurements from more massive galaxies. Our results suggest that despite their low star formation efficiencies, the H I-rich UDGs need not be forming stars in an exotic manner. We also find that the UDGs are likely H2 poor compared even to the overall dwarf population.

Keywords: Dwarf galaxies, Star formation, Low surface brightness galaxies
The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). VII. Chemistry of Embedded Dense Cores. We present a study of the chemistry toward 294 dense cores in 12 molecular clumps, using data obtained from the ALMA Survey of 70 μm dark High-mass clumps in Early Stages. We identified 97 protostellar cores and 197 prestellar core candidates, based on the detection of outflows and molecular transitions of high upper-energy levels (E  u /k &gt; 45 K). The detection rate of the N2D+ emission toward the protostellar cores is 38%, which is higher than 9% for the prestellar cores, indicating that N2D+ does not exclusively trace prestellar cores. The detection rates of the DCO+ emission are 35% for the prestellar cores and 49% for the protostellar cores, which are higher than those for N2D+, implying that DCO+ appears more frequently than N2D+ in both prestellar and protostellar cores. Both the N2D+ and DCO+ abundances appear to decrease from the prestellar to the protostellar stage. The DCN, C2D, and 13CS emission lines are rarely seen in the dense cores of early evolutionary phases. The detection rate of the H2CO emission toward dense cores is 52%, three times higher than that for CH3OH (17%). In addition, the H2CO detection rate, abundance, line intensities, and line widths increase with the core evolutionary status, suggesting that the H2CO line emission is sensitive to protostellar activity.

Keywords: Interstellar line emission, Infrared dark clouds, Massive stars, Star forming regions, Protoclusters, Astrochemistry, Star formation, Interstellar medium, Protostars
Recombination of Hot Ionized Nebulae: The Old Planetary Nebula around V4334 Sgr (Sakurai's Star). After becoming ionized, low-density astrophysical plasmas will begin a process of slow recombination. Models for this still have significant uncertainties. Recombination cannot normally be observed in isolation, because the ionization follows the evolutionary timescale of the ionizing source. Laboratory experiments are unable to reach the appropriate conditions because of the very long required timescales. The extended nebula around the very late helium pulse (VLTP) star V4334 Sgr provides a unique laboratory for this kind of study. The sudden loss of the ionizing UV radiation after the VLTP event has allowed the nebula to recombine free from other influences. More than 290 long-slit spectra taken with FORS1/2 at ESO's Very Large Telescope between 2007 and 2022 are used to follow the time evolution of the lines of H, He, N, S, O, and Ar. Hydrogen and helium lines, representing most of the ionized mass, do not show significant changes. A small increase is seen in [N II] (+2.8% yr-1; 2.7σ significance), while we see a decrease in [O III] (-1.96% yr-1; 2.0σ significance). The [S II] lines show a change of +3.0% yr-1 (1.6σ significance). The lines of [S III] and of [Ar III] show no significant changes. For [S III], the measurement differs from the predicted decrease by 4.5σ. A possible explanation is that the fractions of S3+ and higher are larger than expected. Such an effect could provide a potential solution for the sulfur anomaly in planetary nebulae. * This investigation makes use of ESO data from program IDs 077.D-0394, 079.D-0256, 381.D-0117, 383.D-0427, 385.D-0292, 087.D-0223, 089.D-0080, 091.D-0209, 093.D-0195, 095.D-0113, 097.D-0146, 099.D-0045, and 0109.D-0060.

Keywords: Recombination, Astrophysical processes, Interstellar medium
Photometric Objects Around Cosmic Webs (PAC) Delineated in a Spectroscopic Survey. III. Accurate Measurement of Galaxy Stellar Mass Function with the Aid of Cosmological Redshift Surveys. We present a novel method to accurately measure the galaxy stellar mass function (GSMF) based upon the Photometric objects Around Cosmic webs (PAC) method developed in our first paper (Paper I) of the series. The method allows us to measure the GSMF to a lower-mass end that is not accessible to the spectroscopic sample used in the PAC. Compared with Paper I, the current measurement of GSMF is direct and model independent. We measure the GSMFs in the redshift ranges of z  s  3 3 Throughout the paper, we use z  s  for spectroscopic redshift, z for the z-band magnitude. &lt; 0.2, 0.2 &lt; z  s  &lt; 0.4, and 0.5 &lt; z  s  &lt; 0.7 down to stellar masses of M * = 108.2, 1010.6, and 1010.6 M ⊙, using the data from the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys and the spectroscopic samples of Slogan Digital Sky Survey (i.e., Main, LOWZ, and CMASS samples). Our results show that there is no evolution of GSMF from z  s  = 0.6 to z  s  = 0.1 for M * &gt; 1010.6 M ⊙, and that there is a clear upturn at M * ≈ 109.5 M ⊙ toward smaller galaxies in the local GMSF at z  s  = 0.1. We provide an accurate double Schechter fit to the local GSMF for the entire range of M * and a table of our measurements at the three redshifts, which can be used to test theories of galaxy formation. Our method can achieve an accurate measurement of GSMF to the stellar mass limit where the spectroscopic sample is already highly incomplete (e.g., ~ 10-3) for its target selection.

Keywords: Stellar mass functions, Galaxy formation, Galaxy abundances, Galaxy properties