Sazuna/UAT_keywords huggingface dataset:
Assessment of Callisto Gravity-field Determination Using the Inter-satellite Range-rate Link. China will launch the "Tianwen-IV" mission around 2030, focusing on the orbiting exploration of Jupiter and Callisto, a moon of Jupiter. As part of this ambitious mission, a main satellite will carry another satellite that will be released in the Jupiter system to continue its journey toward Uranus. Considering the current mission planning, we propose an inter-satellite radio-observation mode that differs from the conventional observation mode of tracking from Earth to precisely determine the orbit of the satellites. Given the significance of the Callisto gravity field model in both science objectives and satellite navigation, we have conducted a series of simulation experiments to evaluate the potential of this inter-satellite range-rate data for accurately estimating the Callisto gravity field. The results obtained from the analysis demonstrate that by utilizing 40 days of ground station observations, it is possible to estimate the gravity field model of Callisto up to a degree of 70. Remarkably, when combining these ground station observations with inter-satellite observations, a comparable level of accuracy can be achieved with just 10 days of observations. Furthermore, with reduced inter-satellite observation noise, accuracy improves, enabling estimation up to 80 degrees or higher. Initial inter-satellite distance selection impacts estimation accuracy. These findings serve as a valuable test bed for the future "Tianwen-IV" mission to perform precise orbit determination and gravity field model estimation to reduce reliance on deep space stations.

Keywords: Gravitational fields, Callisto
Two-dimensional Eclipse Mapping of the Hot-Jupiter WASP-43b with JWST MIRI/LRS. We present eclipse maps of the two-dimensional thermal emission from the dayside of the hot-Jupiter WASP-43b, derived from an observation of a phase curve with the JWST MIRI/LRS instrument. The observed eclipse shapes deviate significantly from those expected for a planet emitting uniformly over its surface. We fit a map to this deviation, constructed from spherical harmonics up to order , alongside the planetary, orbital, stellar, and systematic parameters. This yields a map with a meridionally averaged eastward hot-spot shift of (7.75 ± 0.36)°, with no significant degeneracy between the map and the additional parameters. We show the latitudinal and longitudinal contributions of the dayside emission structure to the eclipse shape, finding a latitudinal signal of ∼200 ppm and a longitudinal signal of ∼250 ppm. To investigate the sensitivity of the map to the method, we fix the parameters not used for mapping and derive an "eigenmap" fitted with an optimized number of orthogonal phase curves, which yields a similar map to the map. We also fit a map up to , which shows a smaller hot-spot shift, with a larger uncertainty. These maps are similar to those produced by atmospheric simulations. We conclude that there is a significant mapping signal which constrains the spherical harmonic components of our model up to . Alternative mapping models may derive different structures with smaller-scale features; we suggest that further observations of WASP-43b and other planets will drive the development of more robust methods and more accurate maps.

Keywords: Hot Jupiters, Exoplanet atmospheric dynamics, Extrasolar gaseous giant planets, Exoplanet atmospheres, Exoplanet atmospheric structure
Hα Emission and H II Regions at the Locations of Recent Supernovae in Nearby Galaxies. We present a statistical analysis of the local, ≈50─100 pc scale, Hα emission at the locations of recent (≤125 yr) supernovae (SNe) in nearby star-forming galaxies. Our sample consists of 32 SNe in 10 galaxies that are targets of the PHANGS-MUSE survey. We find that 41% (13/32) of these SNe occur coincident with a previously identified H II region. For comparison, H II regions cover 32% of the area within ±1 kpc of any recent SN. Contrasting this local covering fraction with the fraction of SNe coincident with H II regions, we find a statistical excess of 7.6% ± 8.7% of all SNe to be associated with H II regions. This increases to an excess of 19.2% ± 10.4% when considering only core-collapse SNe (CCSNe). These estimates appear to be in good agreement with qualitative results from new, higher-resolution Hubble Space Telescope Hα imaging, which also suggests many CCSNe detonate near but not in H II regions. Our results appear consistent with the expectation that only a modest fraction of stars explode during the first ≲5 Myr of the life of a stellar population when Hα emission is expected to be bright. Of the H II region associated SNe, 85% (11/13) also have associated detected CO (2─1) emission, indicating the presence of molecular gas. The SNe associated with H II regions have typical extinctions of A  V  ∼ 1 mag, consistent with a significant amount of pre-clearing of gas from the region before the SNe explode.

Keywords: Stellar feedback, Core-collapse supernovae, Star forming regions, Galaxy evolution, H II regions, Supernovae
SCExAO/CHARIS Multiwavelength High-contrast Imaging of the BD+45<SUP>°</SUP>598 Debris Disk. We present a multiwavelength (1.16–2.37 μm) view of the debris disk around BD+45°598, using the Subaru Coronagraphic Extreme Adaptive Optics system paired with the Coronagraphic High Angular Resolution Imaging Spectrograph. With an assumed age of 23 Myr, this source allows us to study the early evolution of debris disks and search for forming planets. We fit a scattered light model to our disk using a differential evolution algorithm, and constrain its geometry. We find the disk to have a peak density radius of R 0 = 109.6 au, an inclination of i = 88.1°, and position angle PA = 111.0°. While we do not detect a substellar companion in the disk, our calculated contrast limits indicate sensitivity to planets as small as ∼10M Jup at a projected separation of 12 au of the star, and as small as ∼4M Jup beyond 38 au. When measuring intensity as a function of wavelength, the disk color constrains the minimum dust grain size within a range of ∼0.13–1.01 μm.

Keywords: Adaptive optics, Direct imaging, Circumstellar disks, Debris disks, Near infrared astronomy
Host-star Properties of Hot, Warm, and Cold Jupiters in the Solar Neighborhood from Gaia Data Release 3: Clues to Formation Pathways. Giant planets exhibit diverse orbital properties, hinting at their distinct formation and dynamic histories. In this paper, using Gaia Data Release 3 (DR3), we investigate if and how the orbital properties of Jupiters are linked to their host star properties, particularly their metallicity and age. We obtain metallicities for main-sequence stars of spectral type F, G, and K, hosting hot, warm, and cold Jupiters with varying eccentricities. We compute the velocity dispersions of the host stars of these three groups using kinematic information from Gaia DR3 and obtain average ages using a velocity dispersion–age relation. We find that the host stars of hot Jupiters are relatively metal rich ([Fe/H] = 0.18 ± 0.13) and young (median age of 3.97 ± 0.51 Gyr) compared to the host stars of cold Jupiters in nearly circular orbits, which are relatively metal poor (0.03 ± 0.18) and older (median age of 6.07 ± 0.79 Gyr). The host stars of cold Jupiters in high-eccentricity orbits, on the other hand, show metallicities similar to those of the hosts of hot Jupiters, but are older, on average (median age of 6.25 ± 0.92 Gyr). The similarity in metallicity between the hosts of hot Jupiters and the hosts of cold Jupiters in high-eccentricity orbits supports high-eccentricity migration as the potential origin of hot Jupiters, with the latter serving as the progenitors of hot Jupiters. However, the average age difference between them suggests that the older hot Jupiters may have been engulfed by their host star over timescales ∼ 6 Gyr. This allows us to estimate the value of stellar tidal quality factor, .

Keywords: Exoplanet migration, Gaia, Hot Jupiters, Tidal interaction, Metallicity
Discovery of RR Lyrae in the Ultra-faint-dwarf Galaxy Virgo III. Virgo III is a newly discovered ultra-faint-dwarf (UFD) candidate, and finding RR Lyrae associated with this galaxy is important to constrain its distance. In this work, we present a search of RR Lyrae in the vicinity of Virgo III based on the time-series r-band images taken from the Lulin One-meter Telescope (LOT). We have identified three RR Lyrae from our LOT data, including two fundamental mode (ab-type) and a first-overtone (c-type) RR Lyrae. Assuming these three RR Lyrae are members of Virgo III, we derived the distance to this UFD as 154 ± 25 kpc, fully consistent with the independent measurements given in the literature. We have also revisited the relation between absolute V-band magnitude (M  V ) and the number of RR Lyrae (of all types, N RRL) found in local galaxies, demonstrating that the M  V -N RRL relation is better described with the specific RR Lyrae frequency.

Keywords: RR Lyrae variable stars, Dwarf galaxies
A Close Binary Lens Revealed by the Microlensing Event Gaia20bof. During the last 25 yr, hundreds of binary stars and planets have been discovered toward the Galactic bulge by microlensing surveys. Thanks to a new generation of large-sky surveys, it is now possible to regularly detect microlensing events across the entire sky. The OMEGA Key Projet at the Las Cumbres Observatory carries out automated follow-up observations of microlensing events alerted by these surveys with the aim of identifying and characterizing exoplanets as well as stellar remnants. In this study, we present the analysis of the binary lens event Gaia20bof. By automatically requesting additional observations, the OMEGA Key Project obtained dense time coverage of an anomaly near the peak of the event, allowing characterization of the lensing system. The observed anomaly in the lightcurve is due to a binary lens. However, several models can explain the observations. Spectroscopic observations indicate that the source is located at ≤2.0 kpc, in agreement with the parallax measurements from Gaia. While the models are currently degenerate, future observations, especially the Gaia astrometric time series as well as high-resolution imaging, will provide extra constraints to distinguish between them.

Keywords: Binary lens microlensing
Masers and Star Formation Activities in W51A. Concurrently with the maser flare observed in W51-North during the 3 month monitoring of H2O, NH3, and CH3OH maser variability from 2020 January to April using the Tianma 65 m Radio Telescope, we conducted Very Large Array mappings for these three maser species across the entirety of W51A region. After finding the ring-shaped H2O maser which might trace the disk surrounding the protostar residing in W51-North, the NH3 (9,6) maser delineated a jet which might be illuminated in the luminosity outburst possibly caused by the infalling streamer's interaction with the protostar's disk. An analysis of the comprehensive distribution of maser spots allowed us to affirm that W51N4 or ALMAmm31 serves as the primary source of the Lacy jet. Furthermore, we observed that class I methanol maser spots may extend beyond the locations of the H2O and NH3 (9,6) masers within the outflow. Additionally, emissions from other NH3 maser transitions coincided with specific 1.3 mm continuum sources. The arrangement of H2O maser spots in the vicinity of W51e2-E potentially indicates episodic accretions in this source. Combining the data from the Atacama Large Millimeter/submillimeter Array data archive for W51-North, W51e2, and W51e8, we have discovered that the H2O, NH3, and CH3OH masers, as well as the HC3N and SiO emissions are found to be good tools for tracing outflow in this work for W51A.

Keywords: Young stellar objects, Star formation, Astrophysical masers, Interstellar masers, Protostars
UV Cooling via O VI Emission in the Superwind of M82 Observed with the Far Ultraviolet Spectroscopic Explorer (FUSE). We examined archival Far Ultraviolet Spectroscopic Explorer data to search for far-ultraviolet emission lines in the starburst galaxy M82. The observations were made in an outflow region that extends beyond the galactic disk. We found the O VI λ λ 1032, 1038 emission lines from the galaxy's southern outflow region. The O VI lines suggest that the outflowing warm-hot gas is undergoing radiative cooling. We measured a radial velocity of ∼420 km s−1 from the O VI lines, which is faster than the velocity seen in Hα observations. The O VI λ1038 emission line seems to be blended with the C II λ1037 emission line, which has a radial velocity of ∼300 km s−1, similar to what is observed in Hα observations. The outflow medium of M82 appears to be composed of gas in multiple phases with varying temperatures and kinematics. Future spectroscopic observations in high energy regimes covering a wider spatial area are necessary to understand better the properties of the warm-hot gas medium in the outflow.

Keywords: Starburst galaxies, Ultraviolet spectroscopy, Circumgalactic medium, Extragalactic astronomy, Galaxies
Grand Design versus Multiarmed Spiral Galaxies: Dependence on Galaxy Structure. We developed an algorithm to use Galaxy Zoo 3D spiral arm masks produced by citizen scientist volunteers to semiautomatically classify spiral galaxies as either multiarmed or grand design spirals. Our final sample consists of 299 multiarmed and 245 grand design galaxies. On average, the grand design galaxies have smaller stellar masses than the multiarmed galaxies. For a given stellar mass, the grand design galaxies have larger concentrations, earlier Hubble types, smaller half-light radii, and larger central surface mass densities than the multiarmed galaxies. Lower-mass galaxies of both arm classes have later Hubble types and lower concentrations than higher-mass galaxies. In our sample, a higher fraction of grand design galaxies have classical bulges rather than pseudo-bulges, compared to multiarmed galaxies. These results are consistent with theoretical models and simulations, which suggest that dense classical bulges support the development and/or longevity of two-armed spiral patterns. Similar specific star formation rates (sSFRs) are found in multiarmed and grand design galaxies with similar stellar masses and concentrations. This implies that the sSFRs in spiral galaxies are a function of concentration and stellar mass, but independent of the number of spiral arms. Our classifications are consistent with arm counts from the Galaxy Zoo 2 project and published m = 3 Fourier amplitudes.

Keywords: Spiral galaxies, Galaxy evolution, Disk galaxies
HIP 65426 is a High-frequency Delta Scuti Pulsator in Plausible Spin–Orbit Alignment with its Directly Imaged Exoplanet. HIP 65426 hosts a young giant planet that has become the first exoplanet directly imaged with JWST. Using time-series photometry from the Transiting Exoplanet Survey Satellite (TESS), we classify HIP 65426 as a high-frequency δ Scuti pulsator with a possible large-frequency separation of Δν = 7.23 ± 0.02 cycles day‑1. We check the TESS data for pulsation-timing variations and use the nondetection to estimate a 95% dynamical mass upper limit of 12.8 M Jup for HIP 65426 b. We also identify a low-frequency region of signal that we interpret as stellar latitudinal differential rotation with two rapid periods of 7.85 ± 0.08 hr and 6.67 ± 0.04 hr. We use our TESS rotation periods together with published values of radius and to jointly measure the inclination of HIP 65426 to °. Our stellar inclination is consistent with the orbital inclination of HIP 65426 b ( °) at the 68% percent level based on our orbit fit using published relative astrometry. The lack of significant evidence for spin–orbit misalignment in the HIP 65426 system supports an emerging trend consistent with preferential alignment between imaged long-period giant planets and their host stars.

Keywords: Stellar pulsations, Delta Scuti variable stars, Exoplanet systems, Planet hosting stars
The Metallicity and Carbon-to-oxygen Ratio of the Ultrahot Jupiter WASP-76b from Gemini-S/IGRINS. Measurements of the carbon-to-oxygen (C/O) ratios of exoplanet atmospheres can reveal details about their formation and evolution. Recently, high-resolution cross-correlation analysis has emerged as a method of precisely constraining the C/O ratios of hot Jupiter atmospheres. We present two transits of the ultrahot Jupiter WASP-76b observed between 1.4 and 2.4 μm with the high-resolution Immersion GRating INfrared Spectrometer on the Gemini-S telescope. We detected the presence of H2O, CO, and OH at signal-to-noise ratios of 6.93, 6.47, and 3.90, respectively. We performed two retrievals on this data set. A free retrieval for abundances of these three species retrieved a volatile metallicity of , consistent with the stellar value, and a supersolar carbon-to-oxygen ratio of C/O . We also ran a chemically self-consistent grid retrieval, which agreed with the free retrieval within 1σ but favored a slightly more substellar metallicity and solar C/O ratio ( and C/O ). A variety of formation pathways may explain the composition of WASP-76b. Additionally, we found systemic (V sys) and Keplerian (K  p ) velocity offsets which were broadly consistent with expectations from 3D general circulation models of WASP-76b, with the exception of a redshifted V sys for H2O. Future observations to measure the phase-dependent velocity offsets and limb differences at high resolution on WASP-76b will be necessary to understand the H2O velocity shift. Finally, we find that the population of exoplanets with precisely constrained C/O ratios generally trends toward super-solar C/O ratios. More results from high-resolution observations or JWST will serve to further elucidate any population-level trends.

Keywords: Exoplanet atmospheric dynamics, Exoplanet atmospheric composition , Observational astronomy, Exoplanet atmospheres
Keck and Hubble Observations Show that MOA-2008-BLG-379Lb is a Super-Jupiter Orbiting an M Dwarf. We present high angular resolution imaging that detects the MOA-2008-BLG-379L exoplanet host star using Keck adaptive optics and the Hubble Space Telescope. These observations reveal host star and planet masses of M host = 0.434 ± 0.065 M ⊙ and m  p  = 2.44 ± 0.49 M Jupiter. They are located at a distance of D  L  = 3.44 ± 0.53 kpc, with a projected separation of 2.70 ± 0.42 au. These results contribute to our determination of exoplanet host star masses for the Suzuki et al. statistical sample, which will determine the dependence of the planet occurrence rate on the mass and distance of the host stars. We also present a detailed discussion of the image-constrained modeling version of the eesunhong light-curve modeling code that applies high angular resolution image constraints to the light-curve modeling process. This code increases modeling efficiency by a large factor by excluding models that are inconsistent with the high angular resolution images. The analysis of this and other events from the Suzuki et al. statistical sample reveals the importance of including higher-order effects, such as microlensing parallax and planetary orbital motion, even when these features are not required to fit the light-curve data. The inclusion of these effects may be needed to obtain accurate estimates of the uncertainty of other microlensing parameters that affect the inferred properties of exoplanet microlens systems. This will be important for the exoplanet microlensing survey of the Roman Space Telescope, which will use both light-curve photometry and high angular resolution imaging to characterize planetary microlens systems.

Keywords: Gravitational microlensing exoplanet detection, Hubble Space Telescope, Galactic bulge, Adaptive optics, Extrasolar gaseous giant planets
A Reference Meteor Magnitude for Intercomparable Fluxes. The rate at which meteors pass through Earth's atmosphere has been measured or estimated many times over; existing flux measurements span at least 12 astronomical magnitudes, or roughly five decades in mass. Unfortunately, the common practice of scaling flux to a universal reference magnitude of +6.5 tends to collapse the magnitude or mass dimension. Furthermore, results from different observation networks can appear discrepant due solely to the use of different assumed population indices, and readers cannot resolve this discrepancy without access to magnitude data. We present an alternate choice of reference magnitude that is representative of the observed meteors and minimizes the dependence of flux on population index. We apply this choice to measurements of recent Orionid meteor shower fluxes to illustrate its usefulness for synthesizing independent flux measurements.

Keywords: Meteors, Meteor showers
The Utility of Infrasound in Global Monitoring of Extraterrestrial Impacts: A Case Study of the 2008 July 23 Tajikistan Bolide. Among the various observational techniques used for the detection of large bolides on a global scale is a low-frequency sound known as infrasound. Infrasound, which is also one of the four sensing modalities used by the International Monitoring System, offers continuous global monitoring and can be leveraged for planetary defense. Infrasonic records can provide an additional dimension for event characterization and a distinct perspective that might not be available through any other observational method. This paper describes the infrasonic detection and characterization of the bolide that disintegrated over Tajikistan on 2008 July 23. This event was detected by two infrasound stations at distances of 1530 and 2130 km. Propagation paths to one of the stations were not predicted by the model, despite being clearly detected. The presence of the signal is attributed to the acoustic energy being trapped in a weak but leaky stratospheric AtmoSOFAR channel. The infrasound signal analysis indicates that the shock originated at the point of the main breakup at an altitude of 35 km. The primary mode of the shock production of the signal detected at the two stations was a spherical blast resulting from the main gross fragmentation episode. The energy estimate, based on the signal period, is 0.17–0.51 kt of TNT equivalent, suggesting a mass of 6.6–23.5 tons. The corresponding object radius, assuming the chondritic origin, was 0.78–1.18 m.

Keywords: Impact phenomena, Near-Earth objects, Fireballs, Asteroids, Bolides, Planetary atmospheres, Planetary bow shocks, Shocks
Verification of Astrometrically Accelerating Stars from Hipparcos and Gaia. I. Methodology and Application to HIP 44842. A large number of candidate binary stars with apparent acceleration on the sky has emerged from analysis of astrometric data collected by the Hipparcos, Tycho-2, and Gaia space missions. Although the apparent acceleration can serve as a relatively reliable indicator of binarity, it provides scarce information about the orbital and physical parameters of the components. With an emphasis on the search for stellar-mass black holes and neutron stars hidden in binary systems, we start a broader effort to characterize the most promising candidates using follow-up ground-based observations. Accurate quantification of orbital and physical parameters of systems with dim or invisible companions requires combination of Hipparcos, Gaia, and precision spectroscopic measurements. In this paper, we review the necessary steps in this implementation and describe the improved Hipparcos–Gaia sample of long-term astrometric accelerations, which includes correction of sky-correlated systematic errors using the vector spherical decomposition method. As an example, we study one Hipparcos star with a large acceleration, HIP 44842, where the companion is revealed to be a normal main-sequence star.

Keywords: Stellar mass black holes, Spectroscopic binary stars, Astrometric binary stars, Astrometry, Proper motions, Gaia