Sazuna/UAT_keywords huggingface dataset:
Characterizing Exoplanetary Atmospheres at High Resolution with SPIRou: Detection of Water on HD 189733 b. We present the first exoplanet atmospheric detection made as part of the SPIRou Legacy Survey, a Large Observing Program of 300 nights exploiting the capabilities of SPIRou, the new near-infrared high-resolution (R ~ 70,000) spectropolarimeter installed on the Canada-France-Hawaii Telescope (3.6 m). We observed two transits of HD 189733b, an extensively studied hot Jupiter that is known to show prominent water vapor absorption in its transmission spectrum. When combining the two transits, we successfully detect the planet's water vapor absorption at 5.9σ using a cross-correlation t-test, or with a ΔBIC &gt; 10 using a log-likelihood calculation. Using a Bayesian retrieval framework assuming parameterized temperature-pressure (T-P) profile atmospheric models, we constrain the planet atmospheric parameters, in the region probed by our transmission spectrum, to the following values: ${\mathrm{log}}_{10}\mathrm{VMR}[{{\rm{H}}}_{2}{\rm{O}}]$ = $-{4.4}_{-0.4}^{+0.4}$ , and P cloud ≳ 0.2 bar (gray clouds), both of which are consistent with previous studies of this planet. Our retrieved water volume-mixing ratio is slightly subsolar; although, combining it with the previously retrieved super-solar CO abundances from other studies would imply a super-solar C/O ratio. We furthermore measure a net blueshift of the planet signal of $-{4.62}_{-0.44}^{+0.46}$ km s-1, which is somewhat larger than many previous measurements and unlikely to result solely from winds in the planet's atmosphere, although it could possibly be explained by a transit signal dominated by the trailing limb of the planet. This large blueshift is observed in all of the different detection/retrieval methods that were performed and in each of the two transits independently.

Keywords: High resolution spectroscopy, Exoplanet atmospheric composition , Hot Jupiters, Atmospheric circulation, Atmospheric clouds, Molecular spectroscopy, Astronomy data analysis, Transmission spectroscopy, Exoplanet astronomy, Atmospheric composition, Exoplanet atmospheres
TIC 172900988: A Transiting Circumbinary Planet Detected in One Sector of TESS Data. We report the first discovery of a transiting circumbinary planet detected from a single sector of Transiting Exoplanet Survey Satellite (TESS) data. During Sector 21, the planet TIC 172900988b transited the primary star and then five days later it transited the secondary star. The binary is itself eclipsing, with a period P ≈ 19.7 days and an eccentricity e ≈ 0.45. Archival data from ASAS-SN, Evryscope, KELT, and SuperWASP reveal a prominent apsidal motion of the binary orbit, caused by the dynamical interactions between the binary and the planet. A comprehensive photodynamical analysis of the TESS, archival and follow-up data yields stellar masses and radii of M 1 = 1.2384 ±0.0007 M ⊙ and R 1 = 1.3827 ± 0.0016 R ⊙ for the primary and M 2 = 1.2019 ± 0.0007 M ⊙ and R 2 = 1.3124 ±0.0012 R ⊙ for the secondary. The radius of the planet is R 3 = 11.25 ± 0.44 R ⊕ (1.004 ± 0.039R Jup). The planet's mass and orbital properties are not uniquely determined-there are six solutions with nearly equal likelihood. Specifically, we find that the planet's mass is in the range of 824 ≲ M 3 ≲ 981 M ⊕ (2.65 ≲ M 3 ≲ 3.09M Jup), its orbital period could be 188.8, 190.4, 194.0, 199.0, 200.4, or 204.1 days, and the eccentricity is between 0.02 and 0.09. At V = 10.141 mag, the system is accessible for high-resolution spectroscopic observations, e.g., the Rossiter-McLaughlin effect and transit spectroscopy.

Keywords: Exoplanet astronomy, Exoplanet detection methods, Eclipsing binary stars, Exoplanets
Testing Models of Triggered Star Formation with Young Stellar Objects in Cepheus OB4. OB associations are home to newly formed massive stars, whose turbulent winds and ionizing flux create H II regions rich with star formation. Studying the distribution and abundance of young stellar objects (YSOs) in these ionized bubbles can provide essential insight into the physical processes that shape their formation, allowing us to test competing models of star formation. In this work, we examined one such OB association, Cepheus OB4 (Cep OB4)-a well-suited region for studying YSOs due to its Galactic location, proximity, and geometry. We created a photometric catalog from Spitzer/Infrared Array Camera (IRAC) mosaics in bands 1 (3.6 μm) and 2 (4.5 μm). We supplemented the catalog with photometry from the Wide-field Infrared Survey Explorer, the Two Micron All Sky Survey, IRAC bands 3 (5.8 μm) and 4 (8.0 μm), MIPS 24 μm, and MMIRS near-infrared data. We used color-color selections to identify 821 YSOs, which we classified using the IR slope of the YSOs' spectral energy distributions, finding 67 Class I, 103 flat spectrum, 569 Class II, and 82 Class III YSOs. We conducted a clustering analysis of the Cep OB4 YSOs and fit their spectral energy distributions. We found many young Class I objects distributed in the surrounding shell and pillars as well as a relative age gradient of unclustered sourcesin the bubble surrounding the OB association, with YSOs generally decreasing in age with distance from the central cluster. Both of these results indicate that the expansion of the H II region may have triggered star formation in CepOB4.

Keywords: Star forming regions, Infrared excess, Young stellar objects, Star formation, Protoplanetary disks
Wolf 503 b: Characterization of a Sub-Neptune Orbiting a Metal-poor K Dwarf. Using radial-velocity measurements from four instruments, we report the mass and density of a 2.043 ±0.069 R ⊕ sub-Neptune orbiting the quiet K-dwarf Wolf 503 (HIP 67285). In addition, we present improved orbital and transit parameters by analyzing previously unused short-cadence K2 campaign 17 photometry and conduct a joint radial-velocity-transit fit to constrain the eccentricity at 0.41 ± 0.05. The addition of a transit observation by Spitzer also allows us to refine the orbital ephemeris in anticipation of further follow-up. Our mass determination, 6.26 ${}_{-0.70}^{+0.69}$ M ⊕ , in combination with the updated radius measurements, gives Wolf 503 b a bulk density of $\rho ={2.92}_{-0.44}^{+0.50}$ g cm-3. Using interior composition models, we find this density is consistent with an Earth-like core with either a substantial H2O mass fraction (45 ${}_{-16}^{+19}$ %) or a modest H/He envelope (0.5% ± 0.3%). The low H/He mass fraction, along with the old age of Wolf 503 (11 ± 2 Gyr), makes this sub-Neptune an opportune subject for testing theories of XUV-driven mass loss while the brightness of its host (J = 8.3 mag) makes it an attractive target for transmission spectroscopy.

Keywords: Ephemerides, Exoplanet astronomy, K dwarf stars, Extrasolar gaseous planets, Radial velocity, Transit photometry
Investigating the Physical Properties and Fragmentation of the AFGL 333-Ridge. We present multiwavelength data to investigate the physical properties and fragmentation of AFGL 333-Ridge. A statistical analysis of velocity dispersion indicates that turbulence is the dominant motion in the ridge. However, the linear mass density (1124.0 M ⊙/pc) of AFGL 333-Ridge far exceeds its critical value of 406.5 M ⊙/pc, suggesting that additional motions are required to prevent the filament radial collapse. Using the getsources algorithm, we identified 14 cores from the Herschel maps, including two protostellar cores and 12 starless cores. All of these starless cores are gravitationally bound, and are therefore considered to be prestellar cores. Based on their radius-mass relation, 11 of 14 cores have the potential to form massive stars. Moreover, the seven cores in two subfilaments of AFGL 333-Ridge seem to constitute two necklace-like chains with a spacing length of 0.51 and 0.45 pc, respectively. Compared the spacing length with theoretical prediction lengths by Jeans and cylindrical fragmentations, we argued that the combination of turbulence and thermal pressure may lead to the fragmentation of the two subfilaments into the cores.

Keywords: Star forming regions, Interstellar filaments
How Complete Are Surveys for Nearby Transiting Hot Jupiters?. Hot Jupiters are a rare and interesting outcome of planet formation. Although more than 500 hot Jupiters (HJs) are known, most of them were discovered by a heterogeneous collection of surveys with selection biases that are difficult to quantify. Currently, our best knowledge of HJ demographics around FGK stars comes from the sample of ≈40 objects detected by the Kepler mission, which have a well-quantified selection function. Using the Kepler results, we simulate the characteristics of the population of nearby transiting HJs. A comparison between the known sample of nearby HJs and simulated magnitude-limited samples leads to four conclusions. (1) The known sample of HJs appears to be ≈75% complete for stars brighter than Gaia G ≤ 10.5, falling to ≲50% for G ≤ 12. (2) There are probably a few undiscovered HJs with host stars brighter than G ≈ 10 located within 10° of the Galactic plane. (3) The period and radius distributions of HJs may differ for F-type hosts (which dominate the nearby sample) and G-type hosts (which dominate the Kepler sample). (4) To obtain a magnitude-limited sample of HJs that is larger than the Kepler sample by an order of magnitude, the limiting magnitude should be approximately G ≈ 12.5. This magnitude limit is within the range for which NASA's Transiting Exoplanet Survey Satellite can easily detect HJs, presenting the opportunity to greatly expand our knowledge of hot-Jupiter demographics.

Keywords: Hot Jupiters, Exoplanets
SOFIA upGREAT/FIFI-LS Emission-line Observations of Betelgeuse during the Great Dimming of 2019/2020. We report NASA-DLR SOFIA upGREAT circumstellar [O I] 63.2 μm and [C II] 157.7 μm emission profiles and FIFI-LS [O I] 63.2 μm, [O I] 145.5 μm, and [C II] 157.7 μm fluxes obtained shortly after Betelgeuse's 2019/2020 Great Dimming event. Haas et al. noted a potential correlation between the [O I] 63.2 μm flux and V magnitude based on three Kuiper Airborne Observatory observations made with the CGS and FIFI instruments. The FIFI observation was obtained when V ≃ 0.88 and revealed a 3σ non-detection at a quarter of the previous CGS flux measurement made when V ≃ 0.35. A potential explanation could be a change in dust-gas drag heating by circumstellar silicates caused by variations in the photospheric radiation field. SOFIA observations provide a unique test of this correlation because the V-band brightness went to its lowest value on record, V ≃ 1.61, with the SOFIA observations being made when V FIFI-LS ≃ 1.51 and V upGREAT ≃ 1.36. The upGREAT spectra show a [O I] 63.2 μm flux larger than previous space observatory measurements obtained when V ≃ 0.58. The profile is consistent with formation in the slower, more turbulent inner S1 outflow, while the [C II] 157.7 μm profile is consistent with formation farther out in the faster S2 outflow. Modeling of dust-gas drag heating, combined with 25 yr of Wing three-filter and V photometry, reveals that it is unlikely that the S1 circumstellar envelope and [O I] 63.2 μm fluxes are dominated by the dust-gas drag heating and that another heating source is also active. The [O I] 63.2 μm profile is hard to reconcile with existing outflow velocity models.

Keywords: Circumstellar envelopes, Massive stars, Far infrared astronomy, Stellar mass loss, Circumstellar dust
A Pre-explosion Extended Effervescent Zone around Core-collapse Supernova Progenitors. I propose a scenario according to which the dense compact circumstellar matter (CSM) that the ejecta of many core-collapse supernovae (CCSNe) collide with within several days after explosion results from a dense zone where in addition to the stellar wind there is gas that does not reach the escape velocity. In this effervescent zone around red supergiant (RSG) stars, there are dense clumps that are ejected from the vicinity of the RSG surface, rise to radii of tens of astronomical units, and then fall back. I consider two simple velocity distributions of the ejected clumps. I find that the density of the bound mass can be tens of times that of the escaping wind, and therefore can mimic a very high mass-loss rate. The dense effervescent compact CSM zone can (1) explain the collision of the ejecta of many CCSNe with a dense compact CSM days after explosion, (2) facilitate very high mass-loss rate if the star experiences powerful pre-explosion activity, (3) form dust that obscures the progenitor in the visible band, and (4) lead to an efficient mass transfer to a stellar companion at separations of tens of astronomical units, if it exists. The effervescent zone might exist for thousands of years and more, and therefore the effervescent CSM model removes the requirement from many type II CCSN progenitors to experience a very strong outburst just years to months before explosion.

Keywords: Type II supernovae, Stellar mass loss
Energy Distribution of Small-scale Flares Derived Using a Genetic Algorithm. To understand the mechanism of coronal heating, it is crucial to derive the contribution of small-scale flares, the so-called nanoflares, to the heating up of the solar corona. To date, several studies have tried to derive the occurrence frequency distribution of flares as a function of energy to reveal the contribution of small-scale flares. However, there are no studies that derive the distribution with considering the following conditions: (1) evolution of the coronal loop plasma heated by small-scale flares, (2) loops smaller than the spatial resolution of the observed image, and (3) multiwavelength observation. To take into account these conditions, we introduce a new method to analyze small-scale flares statistically based on a one-dimensional loop simulation and a machine-learning technique, that is, the genetic algorithm. First, we obtain six channels of Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) light curves of the active-region coronal loops. Second, we carry out many coronal loop simulations and obtain the SDO/AIA light curves for each simulation in a pseudo-manner. Third, using the genetic algorithm, we estimate the best combination of simulated light curves that reproduce the observation. Consequently, the observed coronal loops are heated by small-scale flares with energy flux larger than that typically required to heat up an active region intermittently. Moreover, we derive the occurrence frequency distribution which has various power-law indices in the range from 1-3, which partially supports the nanoflare heating model. In contrast, we find that 90% of the coronal heating is done by flares that have energy larger than 1025 erg.

Keywords: Solar atmosphere, Solar flares, Solar coronal loops, The Sun, Active sun, Solar physics, Solar active regions, Solar corona, Active solar corona
A Diversity of Wave-driven Presupernova Outbursts. Many core-collapse supernova (SN) progenitors show indications of enhanced pre-SN mass loss and outbursts, some of which could be powered by wave energy transport within the progenitor star. Depending on the star's structure, convectively excited waves driven by late-stage nuclear burning can carry substantial energy from the core to the envelope, where the wave energy is dissipated as heat. We examine the process of wave energy transport in single-star SNe progenitors with masses between 11 and 50 M☉. Using MESA stellar evolution simulations, we evolve stars until core collapse and calculate the wave power produced and transmitted to the stars' envelopes. These models improve upon prior efforts by incorporating a more realistic wave spectrum and nonlinear damping effects, reducing our wave-heating estimates by ∼1 order of magnitude compared to prior work. We find that waves excited during oxygen/neon burning typically transmit ∼1046-1047 erg of energy at 0.1-10 yr before core collapse in typical (M &lt; 30 M☉) SN progenitors. High-mass progenitors can often transmit ∼1047-1048 erg of energy during oxygen/neon burning, but this tends to occur later, at about 0.01-0.1 yr before core collapse. Pre-SN outbursts may be most pronounced in low-mass SN progenitors (M ≲ 12 M☉) undergoing semidegenerate neon ignition and in high-mass progenitors (M ≳ 30 M☉) exhibiting convective shell mergers.

Keywords: Massive stars, Stellar mass loss, Circumstellar matter, Stellar oscillations, Supernovae
Magnetic Braking of Accreting T Tauri Stars: Effects of Mass Accretion Rate, Rotation, and Dipolar Field Strength. The rotational evolution of an accreting pre-main-sequence star is influenced by its magnetic interaction with its surrounding circumstellar disk. Using the PLUTO code, we perform 2.5D magnetohydrodynamic, axisymmetric, time-dependent simulations of star-disk interaction—with an initial dipolar magnetic field structure, and a viscous and resistive accretion disk—in order to model the three mechanisms that contribute to the net stellar torque: accretion flow, stellar wind, and magnetospheric ejections (periodic inflation and reconnection events). We investigate how changes in the stellar magnetic field strength, rotation rate, and mass accretion rate (changing the initial disk density) affect the net stellar torque. All simulations are in a net spin-up regime. We fit semi-analytic functions for the three stellar torque contributions, allowing for the prediction of the net stellar torque for our parameter regime, as well as the possibility of investigating spin evolution using 1D stellar evolution codes. The presence of an accretion disk appears to increase the efficiency of stellar torques compared to isolated stars, for cases with outflow rates much smaller than accretion rates, because the star-disk interaction opens more of the stellar magnetic flux compared to that from isolated stars. In our parameter regime, a stellar wind with a mass-loss rate of ≍1% of the mass accretion rate is capable of extracting ≲50% of the accreting angular momentum. These simulations suggest that achieving spin equilibrium in a representative T Tauri case within our parameter regime, e.g., BP Tau, would require a wind mass-loss rate of ≍25% of the mass accretion rate.

Keywords: Stellar evolution, Stellar magnetic fields, Classical T Tauri stars, Stellar winds, Pre-main sequence stars, Stellar accretion, Stellar accretion disks, Stellar rotation, Magnetohydrodynamical simulations
Multiwavelength Analysis and the Difference in the Behavior of the Spectral Features during the 2010 and 2014 Flaring Periods of the Blazar 3C 454.3. Over the years, the flat-spectrum radio quasar 3C 454.3 has presented phases of very high activity (flares) in which the different wave bands increase their flux dramatically. In this work, we perform multiwavelength analysis from radio to gamma-rays and study the Mg II λ2798 emission line and the UV Fe II band from 2008 to 2018. We found that an increase in the 43 GHz flux density of the quasi-stationary component C coincides with the estimated time at which a superluminal blob ejected from the radio core (which caused the brightest flare of 2010) collides with the quasi-stationary component (at a projected distance of ∼4.6 pc from the radio core). The different behavior of the spectral index in the first (5000 &lt; JD - 2,450,000 &lt; 5600) and second (6600 &lt; JD - 2,450,000 &lt; 7900) flaring periods suggests changes in the physical conditions. The complex nature of the second period can be a result of a superposition of multiple events at different locations. The Mg II line has an anticorrelation with the UV continuum while Fe II correlates positively, except at the time of the brightest flare of 2010, when both have a strong response at high continuum luminosities. Our results suggest that the dominant gamma-ray emission mechanism for the first flaring period is external Compton. For the second flaring period the region emitting seed photons is co-spatial with that emitting gamma-rays. However, a study of the spectral energy distribution using a multizone jet emission model is required to confirm the nature of each significant flare during the second period.

Keywords: Quasars, Active galaxies, Galaxy jets, Emission line galaxies, Active galactic nuclei, Gamma-rays
A Mechanism for the Fractionation of Isotopes in <SUP>3</SUP>He-rich Solar Energetic Particle Events. By employing our charge-consistent acceleration model we demonstrate a possibility to explain the isotopic ratios observed in a number of 3He-rich events. We investigate the dependence of isotopic ratios of heavy ions on the energy of the particles, the acceleration efficiency, the product of acceleration time, and the number density of ambient electrons, of the plasma temperature, and of the spectral index of the magnetic fluctuations by which the ions are energized in the acceleration region. On the basis of the energy spectra of heavy ions and their isotopic ratios observed in the event of 2002 August 20 by the Solar Isotope Spectrometer on board the Advanced Composition Explorer (SIS/ACE) we put constraints on the plasma parameters in the acceleration region. Our investigation gives evidence that the spectral index of the fluctuations with which the ions interact is greater than 2, and that the plasma temperature is about 1 MK.

Keywords: Solar energetic particles, Solar abundances, Solar flares
The Pulsating White Dwarf G117-B15A: Still the Most Stable Optical Clock Known. The pulsating hydrogen atmosphere white dwarf star G 117-B15A has been observed since 1974. Its main pulsation period at 215.19738823(63) s, observed in optical light curves, varies by only (5.12 ± 0.82) × 10-15 s s-1 and shows no glitches, as pulsars do. The observed rate of period change corresponds to a change of the pulsation period by 1 s in 6.2 million yr. We demonstrate that this exceptional optical clock can continue to put stringent limits on fundamental physics, such as constraints on interaction from hypothetical dark matter particles, as well as to search for the presence of external substellar companions.

Keywords: White dwarf stars, Late stellar evolution
Lorentz Invariance Violation Limits from the Spectral-lag Transition of GRB 190114C. The spectral lags of gamma-ray bursts (GRBs) have been viewed as the most promising probes of the possible violations of Lorentz invariance (LIV). However, these constraints usually depend on the assumption of the unknown intrinsic time lag in different energy bands and the use of a single highest-energy photon. A new approach to test the LIV effects has been proposed by directly fitting the spectral-lag behavior of a GRB with a well-defined transition from positive lags to negative lags. This method simultaneously provides a reasonable formulation of the intrinsic time lag and robust lower limits on the quantum-gravity energy scales (EQG). In this work, we perform a global fitting to the spectral-lag data of GRB 190114C by considering the possible LIV effects based on a Bayesian approach. We then derive limits on EQG and the coefficients of the standard model extension. The Bayes factor output in our analysis shows very strong evidence for the spectral-lag transition in GRB 190114C. Our constraints on a variety of isotropic and anisotropic coefficients for LIV are somewhat weaker than existing bounds, but they can be viewed as comparatively robust and have the promise to complement existing LIV constraints. The observations of GRBs with higher-energy emissions and higher temporal resolutions will contribute to a better formulation of the intrinsic time lag and more rigorous LIV constraints in the dispersive photon sector.

Keywords: Gravitation, Gamma-ray bursts, Particle astrophysics, Quantum gravity