Sazuna/UAT_keywords huggingface dataset:
Constraints on the Occurrence and Distribution of 1-20 M <SUB>Jup</SUB> Companions to Stars at Separations of 5-5000 au from a Compilation of Direct Imaging Surveys. We present the first statistical analysis of exoplanet direct imaging surveys combining adaptive optics (AO) imaging at small separations with deep seeing-limited observations at large separations allowing us to study the entire orbital separation domain from 5 to 5000 au simultaneously. Our sample of 344 stars includes only confirmed members of nearby young associations and is based on all AO direct-imaging detection limits readily available online, with addition of our own previous seeing-limited surveys. Assuming that the companion distribution in mass and a semimajor axis follows a power-law distribution and adding a dependence on the mass of the host star, such as {d}2n\propto {{fM}}α {a}β {({M}\star /{M}☉ )}γ {dMda}, we constrain the parameters to obtain α =-{0.18}-0.65+0.77, β =-{1.43}-0.24+0.23, and γ ={0.62}-0.50+0.56 at a 68% confidence level, and we obtain f={0.11}-0.05+0.11 for the overall planet occurrence rate for companions with masses between 1 and 20 {M}Jup} in the range of 5-5000 au. Thus, we find that occurrence of companions is negatively correlated with a semimajor axis and companion mass (marginally) but is positively correlated with the stellar host mass. Our inferred mass distribution is in good agreement with other distributions found previously from direct imaging surveys for planets and brown dwarfs, but is shallower as a function of mass than the distributions inferred by radial velocity surveys of gas giants in the 1-3 au range. This may suggest that planets at these wide and very wide separations represent the low-mass tail of the brown dwarfs and stellar companion distribution rather than an extension of the distribution of the inner planets.

Keywords: Brown dwarfs, Direct imaging, Exoplanets
Hot Jupiters Are Destroyed by Tides While Their Host Stars Are on the Main Sequence. While cooler giant planets are often observed with nonzero eccentricities, the short-period circular orbits of hot Jupiters suggest that they lose orbital energy and angular momentum due to tidal interactions with their host stars. However, orbital decay has never been unambiguously observed. We use data from Gaia Data Release 2 to show that hot Jupiter host stars have a smaller Galactic velocity dispersion than a similar population of stars without hot Jupiters. Since Galactic velocity dispersion is correlated with age, this observation implies that the population of hot Jupiter host stars is on average younger than the field population. The best explanation for this inference is that tidal interactions cause hot Jupiters to inspiral while their host stars are on the main sequence. This observation requires that the typical modified stellar tidal quality factor {Q}* {\prime } for solar-type stars is in the range {log}}10{Q}* {\prime }≲ 7.

Keywords: Exoplanet dynamics, Exoplanets, Hot Neptunes, Exoplanet evolution, Exoplanet tides, Tidal interaction
He II Emission from Wolf-Rayet Stars as a Tool for Measuring Dust Reddening. We calibrated a technique to measure dust attenuation in star-forming galaxies. The technique utilizes the stellar-wind lines in Wolf-Rayet stars, which are widely observed in galaxy spectra. The He II 1640 and 4686 features are recombination lines whose ratio is largely determined by atomic physics. Therefore they can serve as a stellar dust probe in the same way as the Balmer lines are used as a nebular probe. We measured the strength of the He II 1640 line in 97 Wolf-Rayet stars in the Galaxy and the Large Magellanic Cloud. The reddening corrected fluxes follow a tight correlation with a fixed ratio of 7.76 for the He II 1640 to 4686 line ratio. Dust attenuation decreases this ratio. We provide a relation between the stellar E(B-V) and the observed line ratio for several attenuation laws. Combining this technique with the use of the nebular Balmer decrement allows the determination of the stellar and nebular dust attenuation in galaxies and can probe its effects at different stellar age and mass regimes, independently of the initial mass function and the star formation history. We derived the dust reddening from the He II line fluxes and compared it to the reddening from the Balmer decrement and from the slope of the ultraviolet continuum in two star-forming galaxies. The three methods result in dust attenuations which agree to within the errors. Future application of this technique permits studies of the stellar dust attenuation compared to the nebular attenuation in a representative galaxy sample.

Keywords: Starburst galaxies, Stellar populations, Young star clusters, Interstellar dust extinction, Interstellar medium, Wolf-Rayet stars
Jupiter's Composition Suggests its Core Assembled Exterior to the N<SUB>2</SUB> Snowline. Jupiter's atmosphere is enriched in C, N, S, P, Ar, Kr, and Xe with respect to solar abundances by a factor of ∼3. Gas giant envelopes are mainly enriched through the dissolution of solids in the atmosphere, and this constant enrichment factor is puzzling since several of the above elements are not expected to have been in the solid phase in Jupiter's feeding zone; most seriously, Ar and the main carrier of N, N2, only condense at the very low temperatures, 21-26 K, associated with the outer solar nebula. We propose that a plausible solution to the enigma of Jupiter's uniform enrichment pattern is that Jupiter's core formed exterior to the N2 and Ar snowlines, beyond 30 au, resulting in a solar composition core in all volatiles heavier than Ne. During envelope accretion and planetesimal bombardment, some of the core mixed in with the envelope, causing the observed enrichment pattern. We show that this scenario naturally produces the observed atmosphere composition, even with substantial pollution from N-poor pebble and planetesimal accretion in Jupiter's final feeding zone. We note that giant core formation at large nebular radii is consistent with recent models of gas giant core formation through pebble accretion, which requires the core to form exterior to Jupiter's current location to counter rapid inward migration during the core and envelope formation process. If this scenario is common, gas giant core formation may account for many of the gaps observed in protoplanetary disks between 10 s and 100 au.

Keywords: Solar nebulae, Solar system formation, Planetary atmospheres, Solar system, Jupiter, Protoplanetary disks, Planet formation
Predicting the Yield of Potential Venus Analogs from TESS and Their Potential for Atmospheric Characterization. The transit method is biased toward short orbital period planets that are interior to their host star’s habitable zone. These planets are particularly interesting from the perspective of exploring runaway greenhouse scenarios and the possibility of potential Venus analogs. Here, we conduct an analysis of predicted Transiting Exoplanet Survey Satellite (TESS) planet yield estimates produced by Huang et al., as well as the TESS Object of Interest (TOI) list resulting from the observations of sectors 1-13 during Cycle 1 of the TESS primary mission. In our analysis we consider potential terrestrial planets that lie within their host star’s Venus zone. These requirements are then applied to a predicted planetary yield from the TESS primary mission and the TOI list, which results in an estimated 259 Venus analogs by the end of the TESS primary mission, and 46 Venus analogs in the TOI list for sectors 1-13. We also calculate the estimated transmission spectroscopy signal-to-noise ratio (S/N) for Venus analogs from the predicted yield and TOI list if they were to be observed by the Near-Infrared Imager and Slitless Spectrograph on the James Webb Space Telescope, as well as update the S/N cutoff values determined by Kempton et al. Our findings show that the best estimated Venus analogs and TOI Venus analogs with R  p  &lt; 1.5 R ⊙ have an estimated transmission spectroscopy S/N &gt; 40 while planets with radii 2 R ⊕ &lt; R  p  &lt; 4 R ⊕ can achieve S/N &gt; 100.

Keywords: Astrobiology
KELT-24b: A 5M <SUB>J</SUB> Planet on a 5.6 day Well-aligned Orbit around the Young V = 8.3 F-star HD 93148. We present the discovery of KELT-24 b, a massive hot Jupiter orbiting a bright (V = 8.3 mag, K = 7.2 mag) young F-star with a period of 5.6 days. The host star, KELT-24 (HD 93148), has a T eff = {6509}-49+50 K, a mass of M * = {1.460}-0.059+0.055 M ⊙, a radius of R * = 1.506 ± 0.022 R ⊙, and an age of {0.78}-0.42+0.61 Gyr. Its planetary companion (KELT-24 b) has a radius of R P = 1.272 ± 0.021 R J and a mass of M P = {5.18}-0.22+0.21 M J, and from Doppler tomographic observations, we find that the planet’s orbit is well-aligned to its host star’s projected spin axis (λ ={2.6}-3.6+5.1). The young age estimated for KELT-24 suggests that it only recently started to evolve from the zero-age main sequence. KELT-24 is the brightest star known to host a transiting giant planet with a period between 5 and 10 days. Although the circularization timescale is much longer than the age of the system, we do not detect a large eccentricity or significant misalignment that is expected from dynamical migration. The brightness of its host star and its moderate surface gravity make KELT-24b an intriguing target for detailed atmospheric characterization through spectroscopic emission measurements since it would bridge the current literature results that have primarily focused on lower mass hot Jupiters and a few brown dwarfs.

Keywords: Exoplanet astronomy, Exoplanet detection methods, Transit photometry, Radial velocity
Stellar Properties of KIC 8736245: An Eclipsing Binary with a Solar-type Star Leaving the Main Sequence. There is a well-known stellar parameter discrepancy for late K and M dwarfs, in that the observed radii and temperatures are often respectively larger and cooler than predicted by theory by several percent. In an ongoing effort to elucidate this issue, we examine the double-lined Kepler eclipsing binary star system KIC 8736245. We supplement the near-continuous 4 yr Kepler light curve with ground-based multicolor photometry from Mount Laguna Observatory and spectroscopy from the Hobby-Eberly Telescope. The binary has an edge-on, circular 5.07 days orbit with stellar masses equal to 0.987 ± 0.009 and 0.782 ± 0.009 M ⊙ and radii of 1.311 ± 0.006 and 0.804 ± 0.004 R ⊙, respectively, and an estimated age of 7-9 Gyr. We find that the stellar radii are consistent with theoretical models within the uncertainties, whereas the temperature of the secondary star is ∼6% cooler than predicted. An important aspect of this work is that the uncertainties derived from a single epoch (individual night of observations) underestimate the overall system parameter uncertainties due to the effect of the 1%-4% fluctuations caused by stellar activity. Our error estimates come from the spread in parameters measured at eight epochs. From the periodicities in the light curve and from the eclipse times, we measure candidate spin periods to be approximately 4.98 and 5.87 days for the primary and secondary star. Surprisingly, these imply super- and subsynchronous rotation compared to the orbital period. Thus KIC 8736245 serves as an interesting case study for the exchange of angular momentum and general stellar astrophysics as stars in binaries evolve off the main sequence.

Keywords: Starspots, Stellar properties, Stellar activity, Eclipsing binary stars, Stellar rotation
Radial Velocity Measurements of HR 8799 b and c with Medium Resolution Spectroscopy. High-contrast medium resolution spectroscopy has been used to detect molecules such as water and carbon monoxide in the atmospheres of gas giant exoplanets. In this work, we show how it can be used to derive radial velocity (RV) measurements of directly imaged exoplanets. Improving upon the traditional cross-correlation technique, we develop a new likelihood based on joint forward modeling of the planetary signal and the starlight background (i.e., speckles). After marginalizing over the starlight model, we infer the barycentric RV of HR 8799 b and c in 2010 yielding -9.2 ± 0.5 km s-1 and -11.6 ± 0.5 km s-1, respectively. These RV measurements help to constrain the 3D orientation of the orbit of the planet by resolving the degeneracy in the longitude of an ascending node. Assuming coplanar orbits for HR 8799 b and c, but not including d and e, we estimate {{Ω }}={89^\circ } -17 +27 and i={20\buildrel{\circ}\over{.} 8} -3.7 +4.5.

Keywords: High resolution spectroscopy, Bayesian statistics, Direct imaging, Astrometry, Radial velocity, Extrasolar gaseous giant planets
The Young Massive Star Cluster Westerlund 2 Observed with MUSE. II. MUSEpack—A Python Package to Analyze the Kinematics of Young Star Clusters. We mapped the Galactic young massive star cluster Westerlund 2 with the integral field spectrograph MUSE (spatial resolution: 0.2 arcsec px-1, spectral resolution: ∆λ = 1.25 Å, wavelength range: 4600-9350 Å) mounted on the Very Large Telescope. We present the fully reduced data set and introduce our new Python package “MUSEpack,” which we developed to measure stellar radial velocities (RVs) with an absolute precision of 1-2 km s-1 without the necessity of a spectral template library. This novel method uses the two-dimensional spectra and an atomic transition line library to create templates around strong absorption lines for each individual star. Automatic, multi-core processing makes it possible to efficiently determine stellar RVs of a large number of stars with the necessary precision to measure the velocity dispersion of young star clusters. MUSEpack also provides an enhanced method for removing telluric lines in crowded fields without sky exposures, and a Python wrapper for ESO’s data reduction pipeline. We observed Westerlund 2 with a total of 11 short and 5 long exposures (survey area: ∼11 arcmin2 or 15.8 pc2) to cover the bright nebular emission and OB stars, as well as the fainter pre-main-sequence stars (≥1 M ☉). We extracted 1725 stellar spectra with a mean signal-to-noise ratio of S/N &gt; 5 per pixel. Typical RV uncertainties of 4.78 km s-1, 2.92 km s-1, and 1.1 km s-1 are reached for stars with a mean S/N &gt; 10, S/N &gt; 20, and S/N &gt; 50 per pixel, respectively. It is possible to reach RV accuracies of 0.9 km s-1, 1.3 km s-1, and 2.2 km s-1 with ≥5, 3-4, and 1-2 spectral lines used to measure the RVs, respectively. The combined statistical uncertainty on the RV measurements is 1.10 km s-1.

Keywords: Radial velocity, Pre-main sequence stars, Young star clusters, Spectroscopy
The Role of Cluster Mass in the Multiple Populations of Galactic and Extragalactic Globular Clusters. Studies based on Hubble Space Telescope (HST) photometry in F275W, F336W, and F438W have shown that the incidence and complexity of multiple populations (MPs) in globular clusters (GCs) depend on cluster mass. This result, however, is based on nearby, low-reddening Galactic GCs, for which we can obtain accurate F275W photometry. In this work, we exploit HST photometry in F336W, F438W, and F814W to characterize MPs in 68 Galactic and extragalactic GCs by using the pseudocolor C F336W,F438W,F814W, which is more efficient in terms of observation time than the pseudocolor C F275W,F336W,F438W adopted in previous works. We first analyze the Galactic GCs alone and find that the red giant branch (RGB) color width strongly correlates with [Fe/H]. After removing the dependence from metallicity, we obtain a strong correlation with cluster mass, thus confirming previous findings. We then exploit the RGB width to compare MPs in Galactic and extragalactic GCs. Similarly to Galactic GCs, the RGB width of Magellanic Cloud (MC) GCs correlates with cluster mass after removing the dependence from metallicity. This fact demonstrates that cluster mass is the main factor affecting the properties of MPs. The MC clusters exhibit, on average, narrower RGBs than Galactic GCs with similar mass and metallicity. We suggest that this difference is a signature of stellar mass loss in Galactic GCs. As an alternative, the mass-RGB-width relation would depend on the host galaxy. Finally, we use ground-based photometry to investigate Terzan 7 through the C  U,B,I  pseudocolor, ground-based analogs of C F336W,F438W,F814W and find that this cluster is consistent with a simple population.

Keywords: Globular star clusters, RGB photometry, Stellar populations, Chemical enrichment, Sagittarius dwarf spheroidal galaxy, Magellanic Clouds, Milky Way Galaxy
Compositional Constraints for Lucy Mission Trojan Asteroids via Near-infrared Spectroscopy. We report near-infrared (0.7-2.5 μm) reflectance spectra for each of the six target asteroids of the forthcoming NASA Discovery-class mission Lucy. Five Jupiter Trojans (the binary (617) Patroclus system, (3548) Eurybates, (21900) Orus, (11351) Leucus, and (15094) Polymele) are well characterized, with measurable spectral differences. We also report a survey-quality spectrum for main-belt asteroid (52246) Donaldjohanson. We measured a continuum of spectral slopes including “red” (Orus, Leucus), “less red” (Eurybates, Patroclus-Menoetius), and intermediate (Polymele), indicating a range of compositional end-members or geological histories. We perform radiative transfer modeling of several possible surface compositions. We find that the mild-sloped spectra and low albedo of Patroclus and Eurybates imply similar compositions. Eurybates (∼7 wt.% water ice) and Patroclus (∼4 wt.% water ice) are consistent with a hydrated surface. Models for Orus and Leucus are consistent with each other and require a significantly more reddening agent (e.g., iron-rich silicates or tholin-like organics). Polymele has a linear spectrum like Patroclus, but a higher albedo more closely aligned with Orus/Leucus, defying simple grouping. Solar system formation models generally predict that the Jovian Trojans accreted in the outer solar system. Our observations and analysis are generally consistently with this expectation, although not uniquely so.

Keywords: Asteroids, Small Solar System bodies, Solar system, Jupiter trojans, Trojan asteroids, Spectroscopy, Flyby missions, Near infrared astronomy
Revisiting the Advanced Thermal Physical Model: New Perspectives on Thermophysical Characteristics of (341843) 2008 EV5 from Four-band WISE Data with the Sunlight-reflection Model. In this paper, we investigate thermophysical characteristics of near-Earth asteroid (341843) 2008 EV5, based on our improved advanced thermal physical model by considering the contribution of sunlight reflection for rough surfaces, along with four waveband observations from the Wide-field Infrared Survey Explorer and the radar-derived shape model. Here we derive that 2008 EV5 has a relatively low thermal inertia of {{Γ }}={110}-12+40 {{J}} {{{m}}}-2 {{{s}}}-1/2 {{{K}}}-1 but a high roughness fraction. The geometric albedo and effective diameter are then constrained to be {p}v={0.095}-0.003+0.016 and {D}eff}={431}-33+6 {{m}}, respectively. The low thermal inertia indicates that 2008 EV5 may have undergone sufficient space weathering over secular evolution. The high roughness may have resemblance to the appearances of Bennu and Ryugu recently observed by spacecraft, where a great number of boulders are widely distributed on the asteroid’s surface. Moreover, we numerically perform 1000 backward simulations of 2008 EV5's cloned orbits within 1 Myr to explore its origin, and present a probability of ∼6.1% that the asteroid originates from the main belt. Finally, we estimate that the mean grain size of the surface ranges from 0.58 to 1.3 mm, and infer that it is unlikely to find water ice on most of the area of 2008 EV5, but there may exist water ice on high latitudes near the polar region.

Keywords: Near-Earth objects
Kojima-1Lb Is a Mildly Cold Neptune around the Brightest Microlensing Host Star. We report the analysis of additional multiband photometry and spectroscopy and new adaptive optics (AO) imaging of the nearby planetary microlensing event TCP J05074264+2447555 (Kojima-1), which was discovered toward the Galactic anticenter in 2017 (Nucita et al.). We confirm the planetary nature of the light-curve anomaly around the peak while finding no additional planetary feature in this event. We also confirm the presence of apparent blending flux and the absence of significant parallax signal reported in the literature. The AO image reveals no contaminating sources, making it most likely that the blending flux comes from the lens star. The measured multiband lens flux, combined with a constraint from the microlensing model, allows us to narrow down the previously unresolved mass and distance of the lens system. We find that the primary lens is a dwarf on the K/M boundary (0.581 ± 0.033 M ⊙) located at 505 ± 47 pc, and the companion (Kojima-1Lb) is a Neptune-mass planet (20.0 ± 2.0 M ⊕) with a semimajor axis of {1.08}-0.18+0.62 au. This orbit is a few times smaller than those of typical microlensing planets and is comparable to the snow-line location at young ages. We calculate that the a priori detection probability of Kojima-1Lb is only ∼35%, which may imply that Neptunes are common around the snow line, as recently suggested by the transit and radial velocity techniques. The host star is the brightest among the microlensing planetary systems (K  s  = 13.7), offering a great opportunity to spectroscopically characterize this system, even with current facilities.

Keywords: Gravitational microlensing, Exoplanet systems
Model of the Search for Extraterrestrial Intelligence with Coronagraphic Imaging. We present modeled detection limits of the Gemini Planet Imager (GPI) and the Wide-Field Infrared Space Telescope (WFIRST) to an optical and infrared laser which could be used by an extraterrestrial civilization to signal their presence. GPI and WFIRST could utilize a coronagraph to search for extraterrestrial intelligence in the present and future. We use archival data for GPI stars and simulated WFIRST observations to find the detectable flux ratio of a laser signal to residual scattered starlight around the target star. This flux ratio is then converted to detectable power as a function of distance from the parent star. For GPI, we assume a monochromatic laser wavelength of 1.55 μm and a wavelength of 575 nm for WFIRST. We assume that the lasers are projected through a 10 m aperture, and that the intensity of the laser beam follows a Gaussian profile. Our analysis is performed on six stars with spectral types later than F within 20 pc (with an emphasis on solar analogs at different distances). The most notable result is the detection limit for τ Ceti, a G5V star with four known exoplanets, two of those within the habitable zone (HZ). The result shows that a 24 kW laser is detectable from τ Ceti from outside of the HZ with GPI and a 7.3 W laser is detectable from within τ Ceti’s HZ by WFIRST.

Keywords: Astronomical techniques, Coronagraphic imaging, Direct imaging
First Detection of CS Masers around a High-mass Young Stellar Object, W51 e2e. We report the discovery of maser emission in the two lowest rotational transitions of CS toward the high-mass protostar W51 e2e with the Atacama Large Millimeter/submillimeter Array and the Jansky Very Large Array. The masers from CS J = 1-0 and J = 2-1 are neither spatially nor spectrally coincident (they are separated by ∼150 au and ∼30 {km} {{s}}{}-1), but both appear to come from the base of the blueshifted outflow from this source. These CS masers join a growing list of rarely detected maser transitions that may trace a unique phase in the formation of high-mass protostars.

Keywords: Star forming regions, Astrophysical masers, Interstellar masers