Latest in astro-ph.sr

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Massive star feedback in clusters: variation of the FUV interstellar radiation field in time and spaceJun 13 2019We investigate radiative feedback from a 34 M$_\odot$ star in a $10^4$ M$_\odot$ turbulent cloud using three-dimensional radiation-hydrodynamics (RHD) models. We use Monte Carlo radiative transfer to accurately compute photoionization equilibrium and ... More
Self-Organized Criticality in Solar and Stellar Flares: Are Extreme Events Scale-Free ?Jun 13 2019We search for outliers in extreme events of statistical size distributions of astrophysical data sets, motivated by the {\sl Dragon-King hypothesis} of Sornette (2009), which suggests that the most extreme events in a statistical distribution may belong ... More
Global Energetics of Solar Flares: VIII. The Low-Energy CutoffJun 13 2019One of the key problems in solar flare physics is the determination of the low-energy cut-off; the value that determines the energy of nonthermal electrons and hence flare energetics. We discuss different approaches to determine the low-energy cut-off ... More
Type IIn supernova light-curve properties measured from an untargeted survey sampleJun 13 2019We present a sample of supernovae Type IIn (SNe IIn) from the untargeted, magnitude-limited surveys of the Palomar Transient Factory (PTF) and its successor, iPTF. SNe IIn found and followed by the PTF/iPTF were used to select a sample of 42 events with ... More
Global Energetics of Solar Flares: VII. Aerodynamic Drag in Coronal Mass EjectionsJun 13 2019The free energy that is dissipated in a magnetic reconnection process of a solar flare, generally accompanied by a coronal mass ejection (CME), has been considered as the ultimate energy source of the global energy budget of solar flares in previous statistical ... More
On the interpretation of Parker Solar Probe Turbulent SignalsJun 13 2019In this letter we propose a practical methodology to interpret future Parker Solar Probe (PSP) turbulent time signals even when Taylor's hypothesis is not valid. By extending Kraichnan's sweeping model used in hydrodynamics we derive the Eulerian spacetime ... More
Evolutionary models for ultracool dwarfsJun 13 2019Ultracool dwarfs have emerged as key targets for searches of transiting exoplanets. Precise estimates of the host parameters (including mass, age, and radius) are fundamental to constrain the physical properties of orbiting exoplanets. We have extended ... More
Activity and rotation of the X-ray emitting Kepler starsJun 13 2019The relation between magnetic activity and rotation in late-type stars provides fundamental information on stellar dynamos and angular momentum evolution. Rotation/activity studies found in the literature suffer from inhomogeneity in the measure of activity ... More
Models for Weak Wind and Momentum Problems in the Winds of Hot StarsJun 13 2019We pesent models for the velocity structure in the supersonic part of hot star winds in order to estimate the effects of clumping in density and velocity. XSTAR (Kallman,2018) was used to calculate radiation pressure in spectral lines (force multiplier ... More
Local semi-analytic models of magnetic flux transport in protoplanetary discsJun 13 2019The evolution of a large-scale poloidal magnetic field in an accretion disc is an important problem because it determines the launching of winds and the feasibility of the magnetorotational instability to generate turbulence or channel flows. Recent studies, ... More
Evidence from stellar rotation for early disc dispersal owing to close companionsJun 13 2019Young low-mass stars of equal-mass exhibit a distribution of rotation periods. At the very early phases of stellar evolution, this distribution is set by the star-disc locking mechanism. The primordial disc lifetime and, consequently, the duration of ... More
HL Tau disk in HCO+ (3-2) and (1-0) with ALMA: gas density, temperature, gap, and one-arm spiralJun 13 2019We present our observational results of the 1.1 mm continuum and the HCO+ (3-2) line in HL Tau at angular resolutions of 0.1" obtained with ALMA and our data analysis of the 2.9 mm and 1.1 mm continuum and the HCO+ (3-2) and (1-0) lines of the HL Tau ... More
ALMA observations of molecular gas in the host galaxy of AT2018cowJun 13 2019We investigate the molecular gas in, and star-formation properties of, the host galaxy (CGCG 137-068) of a mysterious transient, AT2018cow, at kpc and larger scales, using archival band-3 data from the Atacama Large Millimeter/submillimeter Array (ALMA). ... More
Streaming instability: saturation in turbulent protoplanetary disksJun 12 2019The streaming instability for solid particles in protoplanetary disks is re-examined assuming the familiar alpha ($\alpha$) model for isotropic turbulence. Turbulence always reduces the growth rates of the streaming instability relative to values calculated ... More
Probing the shape of the mixing profile and of the thermal structure at the convective core boundary through asteroseismologyJun 12 2019Aims: We investigate from a theoretical perspective if space asteroseismology can be used to distinguish between different thermal structures and shapes of the near-core mixing profiles for different types of coherent oscillation modes in massive stars ... More
Long-Lived Eccentricities in Accretion DisksJun 12 2019Accretion disks can be eccentric: they support $m=1$ modes that are global and slowly precessing. But whether the modes remain trapped in the disk---and hence are long-lived---depends on conditions at the outer edge of the disk. Here we show that in disks ... More
On The XUV Luminosity Evolution of TRAPPIST-1Jun 12 2019We model the long-term XUV luminosity of TRAPPIST-1 to constrain the evolving high-energy radiation environment experienced by its planetary system. Using Markov Chain Monte Carlo (MCMC), we derive probabilistic constraints for TRAPPIST-1's stellar and ... More
Flying far and fast: the distribution of distant hypervelocity star candidates from Gaia DR2 dataJun 12 2019Context. Hypervelocity stars move fast enough to leave the gravitational field of their home galaxies and venture into intergalactic space. The most extreme examples known have estimated speeds in excess of 1000 km/s. These can be easily induced at the ... More
Hydrodynamical instabilities in superfluid neutron stars with background flows between the componentsJun 12 2019The interiors of mature neutron stars are expected to be superfluid. Superfluidity of matter on the microscopic scale can have a number of large scale, potentially observable consequences, as the superfluid component of the star can now flow relative ... More
Effect of Star Rotation Rates on the Characteristics of Energetic Particle EventsJun 12 2019Recent detection of superflares on solar-type stars by Kepler mission raised a possibility that they can be associated with energetic coronal mass ejections (CMEs) and energetic particle events (SEPs). These space weather events can impact habitability ... More
Dynamics of magnetic flux tubes in accretion discs of T Tauri starsJun 12 2019Dynamics of slender magnetic flux tubes (MFT) in the accretion discs of T Tauri stars is investigated. We perform simulations taking into account buoyant, aerodynamic and turbulent drag forces, radiative heat exchange between MFT and ambient gas, magnetic ... More
The Discovery of Six Recycled Pulsars from the Arecibo 327-MHz Drift-Scan Pulsar SurveyJun 12 2019Recycled pulsars are old ($\gtrsim10^{8}$ yr) neutron stars that are descendants from close, interacting stellar systems. In order to understand their evolution and population, we must find and study the largest number possible of recycled pulsars in ... More
Multiple Stellar Populations in NGC 2808: a Case Study for Cluster AnalysisJun 12 2019In the massive globular cluster NGC 2808, RGB stars form at least five distinct groups in the so-called chromosome map photometric plane, arguably corresponding to different stellar populations. While a human expert can separate the groups by eye relatively ... More
The Effect of Binarity on Circumstellar Disk EvolutionJun 12 2019We present new results on how the presence of stellar companions affects disk evolution based on a study of the 5-11 Myr old Upper Scorpius OB Association. Of the 50 G0-M3 Upper Sco members with disks in our sample, only seven host a stellar companion ... More
Influence of 3D plasmoid dynamics on the transition from collisional to kinetic reconnectionJun 12 2019Within the resistive magnetohydrodynamic model, high-Lundquist number reconnection layers are unstable to the plasmoid instability, leading to a turbulent evolution where the reconnection rate can be independent of the underlying resistivity. However, ... More
Hard state accretion disk winds from black holes: the revealing case of MAXI J1820+070Jun 11 2019We report on a detailed optical spectroscopic follow-up of the black hole transient MAXI J1820+070 (ASASSN-18ey). The observations cover the main part of the X-ray binary outburst, when the source alternated between hard and soft states following the ... More
Photometry of Beta Lyrae in 2018 by the BRITE satellitesJun 11 2019Observations of Beta Lyr in four months of 2018 by three BRITE Constellation satellites (the red-filter BTr and BHr, and the blue-filter BLb) permitted a first, limited look into the light-curve variability in two spectral bands. The variations were found ... More
Detailed chemical composition and orbit of the new globular cluster FSR1758: Implications for the accretion of the Sequoia dwarf galaxy onto the Milky WayJun 11 2019We present detailed chemical abundances, radial velocities and orbital parameters for FSR 1758, a recently discovered star cluster in the direction of the Galactic Bulge. High resolution (R~42,000) spectra were obtained using the Magellan/Clay telescope ... More
Dissecting a disk-instability outburst in a symbiotic star: $NuSTAR$, and $Swift$ observations of T Coronae Borealis during the rise to the "super-active" stateJun 11 2019The current $super-active$ state of the recurrent nova T CrB has been observed with unprecedented detail. Previously published observations provide strong evidence that this state is due to an enhancement of the flow of material through the accretion ... More
Mass Loss from the Exoplanet WASP-12b Inferred from $\textit{Spitzer}$ Phase CurvesJun 11 2019Jun 13 2019The exoplanet WASP-12b is the prototype for the emerging class of ultra-hot, Jupiter-mass exoplanets. Past models have predicted---and near ultra-violet observations have shown---that this planet is losing mass. We present an analysis of two sets of 3.6 ... More
Mass Loss from the Exoplanet WASP-12b Inferred from $\textit{Spitzer}$ Phase CurvesJun 11 2019The exoplanet WASP-12b is the prototype for the emerging class of ultra-hot, Jupiter-mass exoplanets. Past models have predicted---and near ultra-violet observations have shown---that this planet is losing mass. We present an analysis of two sets of 3.6 ... More
A Massive Magnetic Helium Atmosphere White Dwarf Binary in a Young Star ClusterJun 11 2019We have searched the Gaia DR2 catalogue for previously unknown hot white dwarfs in the direction of young open star clusters. The aim of this experiment was to try and extend the initial-final mass relation (IFMR) to somewhat higher masses, potentially ... More
Double-peaked OI profile: a likely signature of the gaseous ring around KH 15DJun 11 2019KH 15D is a well-known spectroscopic binary because of its unique and dramatic photometric variability. The variability is explained by a circumbinary dust ring but the ring itself was never directly detected. We present a new interpretation of the double-peaked ... More
Minimum main sequence mass in quadratic Palatini $f(\mathcal{R})$ gravityJun 11 2019General Relativity yields an analytical prediction of a minimum required mass of roughly $\sim 0.08-0.09 M_{\odot}$ for a star to stably burn sufficient hydrogen to fully compensate photospheric losses and, therefore, to belong to the main sequence. Those ... More
The binary millisecond pulsar PSR J1023+0038 -- II. Optical spectroscopyJun 11 2019We present time-resolved optical spectroscopy of the `redback' binary millisecond pulsar system PSR J1023+0038 during both its radio pulsar (2009) and accretion disc states (2014 and 2016). We provide observational evidence for the companion star being ... More
The Formation of Bimodal Dust Species in Nova Ejecta I: Chemical ConditionsJun 11 2019The formation of bimodal dust species (that is, both of silicate and amorphous carbon dust grains are observed in a nova eruption) in nova ejecta is still debated. Using the Modules for Experiments in Stellar Astrophysics code and considering the effects ... More
Six new rapidly oscillating Ap stars in the Kepler long-cadence data using super-Nyquist asteroseismologyJun 11 2019We perform a search for rapidly oscillating Ap stars in the Kepler long-cadence data, where true oscillations above the Nyquist limit of 283.21 {\mu}Hz can be reliably distinguished from aliases as a consequence of the barycentric time corrections applied ... More
The metallicity sensitivity of a surface brightness temperature scaleJun 10 2019To obtain the accuracy now sought in the extragalactic distance scale through standard candles and rulers, calibration of stellar photometry must be improved. The sensitivity of the V-K color surface brightness relation is examined here by means of model ... More
Lyman-alpha in the GJ 1132 System: Stellar Emission and Planetary Atmospheric EvolutionJun 10 2019GJ 1132b, which orbits an M dwarf, is one of the few known Earth-sized planets, and at 12 pc away it is one of the closest known transiting planets. Receiving roughly 19x Earth's insolation, this planet is too hot to be habitable but can inform us about ... More
The study of unclassified B[e] stars and candidates in the Galaxy and Magellanic CloudsJun 10 2019We investigated 12 unclassified B[e] stars or candidates, 8 from the Galaxy, 2 from the Large Magellanic Cloud (LMC) and 2 from the Small Magellanic Cloud (SMC). Based on the analysis of high-resolution spectroscopic (FEROS) and photometric data, we confirmed ... More
Radiation pressure clear-out of dusty photoevaporating discsJun 10 2019Theoretical models of protoplanetary disc dispersal predict a phase where photoevaporation has truncated the disc at several AU, creating a pressure trap which is dust-rich. Previous models predicted this phase could be long-lived (~Myr), contrary to ... More
Revisiting the 16 Cygni planet host at unprecedented precision and exploring automated tools for precise abundancesJun 10 2019The binary system 16 Cygni is key in studies of the planet-star chemical composition connection, as only one of the stars is known to host a planet. This allows us to better assess the possible influence of planet interactions on the chemical composition ... More
Maximally Rotating Supermassive Stars at the Onset of Collapse: Effects of Gas PressureJun 10 2019Jun 12 2019The "direct collapse" scenario has emerged as a promising evolutionary track for the formation of supermassive black holes early in the Universe. In an idealized version of such a scenario, a uniformly rotating supermassive star spinning at the mass-shedding ... More
Maximally Rotating Supermassive Stars at the Onset of Collapse: Effects of Gas PressureJun 10 2019The "direct collapse" scenario has emerged as a promising evolutionary track for the formation of supermassive black holes early in the Universe. In an idealized version of such a scenario, a uniformly rotating supermassive star spinning at the mass-shedding ... More
Explosions Driven by the Coalescence of a Compact Object with the Core of a Massive-Star Companion Inside a Common Envelope: Circumstellar Properties, Light Curves, and Population StatisticsJun 10 2019We model explosions driven by the coalescence of a black hole or neutron star with the core of its massive-star companion. Upon entering a common envelope phase, a compact object may spiral all the way to the core. The concurrent release of energy is ... More
Bayesian analysis of capture reactions $^3\mathrm{He}(α,γ)^7\mathrm{Be}$ and $^3\mathrm{H}(α,γ)^7\mathrm{Li}$Jun 10 2019Bayesian analysis of the radiative capture reactions $^3\mathrm{He}(\alpha,\gamma)^7\mathrm{Be}$ and $^3\mathrm{H}(\alpha,\gamma)^7\mathrm{Li}$ are performed to draw inferences about the cross sections at threshold. We do a model comparison of two competing ... More
Diffusion regions and 3D energy mode development in spontaneous reconnectionJun 10 2019The understanding of magnetic reconnection in three-dimension (3D) is far shallower than its counterpart in two-dimension (2D) due to its potential complication, not to mention the evolving of the spontaneously growing turbulence. We investigate the reason ... More
A 5D view of the Alpha Per, Pleiades, and Praesepe clustersJun 10 2019Aims: Our scientific goal is to provide revised membership lists of the Alpha Per, Pleiades, and Praesepe clusters exploiting the second data release of Gaia and produce five-dimensional maps (ra, dec, parallax, pmRA, pmDEC) of these clusters. Methods: ... More
The period-luminosity relation of red supergiants with Gaia DR2Jun 10 2019Jun 11 2019We revisit the K -band period-luminosity (P-L) relations of Galactic red supergiants using Gaia Data Release 2 parallaxes and up to 70 yr of photometry from AAVSO and ASAS campaigns. In addition, we examine 206 LMC red supergiants using 50 yr of photometric ... More
The period-luminosity relation of red supergiants with Gaia DR2Jun 10 2019We revisit the K -band period-luminosity (P-L) relations of Galactic red supergiants using Gaia Data Release 2 parallaxes and up to 70 yr of photometry from AAVSO and ASAS campaigns. In addition, we examine 206 LMC red supergiants using 50 yr of photometric ... More
The period-luminosity relation of red supergiants with Gaia DR2Jun 10 2019Jun 12 2019We revisit the K -band period-luminosity (P-L) relations of Galactic red supergiants using Gaia Data Release 2 parallaxes and up to 70 yr of photometry from AAVSO and ASAS campaigns. In addition, we examine 206 LMC red supergiants using 50 yr of photometric ... More
A global two-scale helicity proxy from $π$-ambiguous solar magnetic fieldsJun 10 2019If the alpha effect plays a role in the generation of the Sun's magnetic field, the field should show evidence of magnetic helicity of opposite signs at large and small length scales. Measuring this faces two challenges: (i) in weak-field regions, horizontal ... More
Targeted search for young radio pulsars in the SMC: Discovery of two new pulsarsJun 10 2019We report the first rotation powered pulsars discovered in the Small Magellanic Cloud (SMC) in more than a decade. PSR J0043-73 and PSR J0052-72 were discovered during a Parkes Multi-Beam (PMB) survey of MCSNR J0127-7332, and five new, optically selected, ... More
The Ultracool SpeXtroscopic Survey. I. Volume-Limited Spectroscopic Sample and Luminosity Function of M7$-$L5 Ultracool DwarfsJun 08 2019We present a volume-limited, spectroscopically-verified sample of M7$-$L5 ultracool dwarfs within 25\,pc. The sample contains 410 sources, of which $93\%$ have trigonometric distance measurements ($80\%$ from \textit{Gaia} DR2), and $81\%$ have low-resolution ... More
High resolution observations with ARTEMIS-JLS and the NRH (IIb) Spectroscopy and imaging of fiber burstsJun 08 2019Aims: We study the characteristics of intermediate drift bursts (fibers) embedded in the July 14, 2000 large solar event. Methods: We used dynamic spectra from the acousto-optic analyzer (SAO) of the ARTEMIS-JLS solar radiospectrograph, in conjunction ... More
Understanding Heating in Active Region Cores through Machine Learning I. Numerical Modeling and Predicted ObservablesJun 07 2019To adequately constrain the frequency of energy deposition in active region cores in the solar corona, systematic comparisons between detailed models and observational data are needed. In this paper, we describe a pipeline for forward modeling active ... More
Coronal Loop Scaling Laws for Various Forms of Parallel Heat ConductionJun 07 2019The solar atmosphere is dominated by loops of magnetic flux which connect the multi-million-degree corona to the much cooler chromosphere. The temperature and density structure of quasi-static loops is determined by the continuous flow of energy from ... More
Analysis of putative exoplanetary signatures found in light curves of two sdBV stars observed by KeplerJun 07 2019$\bf{Context}$. We investigate the validity of the claim that invokes two extreme exoplanetary system candidates around the pulsating B-type subdwarfs KIC 10001893 and KIC 5807616 from the primary $\it{Kepler}$ field. $\bf{Aims}$. Our goal was to find ... More
KELT-24b: A 5M$_{\rm J}$ Planet on a 5.6 day Well-Aligned Orbit around the Young V=8.3 F-star HD 93148Jun 07 2019We 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 $T_{\rm eff}$ =$6508\pm49$ K, a mass of $M_{*}$ = $1.461^{+0.056}_{-0.060}$ ... More
The search for multiple populations in Magellanic Clouds clusters - V. Correlation between cluster age and abundance spreadsJun 07 2019In our HST photometric survey, we have been searching for multiple stellar populations (MPs) in Magellanic Clouds (MCs) massive star clusters which span a significant range of ages ($\sim 1.5-11$ Gyr). In the previous papers of the series, we have shown ... More
A Census Star Formation in the Outer Galaxy: the SMOG fieldJun 07 2019In this paper we undertake a study of the 21 square degree SMOG field, a Spitzer cryogenic mission Legacy program to map a region of the outer Milky Way towards the Perseus and Outer spiral arms with the IRAC and MIPS instruments. We identify 4648 YSOs ... More
The Degree of Alignment Between Circumbinary Disks and Their Binary HostsJun 07 2019All four circumbinary (CB) protoplanetary disks orbiting short-period ($P < 20$ day) double-lined spectroscopic binaries (SB2s)---a group that includes UZ Tau E, for which we present new ALMA data---exhibit sky-plane inclinations $i_{\rm disk}$ which ... More
Probing the initial conditions of high-mass star formation. III. Fragmentation and triggered star formationJun 07 2019Massive clumps tend to fragment into clusters of cores and condensations, some of which form high-mass stars. In this work, we study the structure of massive clumps at different scales, analyze the fragmentation process, and investigate the possibility ... More
Survey of Li-rich giants among Kepler and LAMOST fields: Determination of Li-rich giants Evolutionary PhaseJun 07 2019In this letter, we report the discovery of 24 new super Li-rich (A(Li) $\ge$ 3.2) giants of He-core burning phase at red clump region. Results are based on systematic search of a large sample of about 12,500 giants common to the LAMOST spectroscopic and ... More
Modeling a Carrington-scale Stellar Superflare and Coronal Mass Ejection from $κ^{1}Cet$Jun 07 2019Observations from the Kepler mission have revealed frequent superflares on young and active solar-like stars. Superflares result from the large-scale restructuring of stellar magnetic fields, and are associated with the eruption of coronal material (a ... More
Opacity distribution functions for stellar spectra synthesisJun 07 2019Contex. Stellar spectra synthesis is essential for the characterization of potential planetary hosts. In addition, comprehensive stellar variability calculations with fast radiative transfer are needed to disentangle planetary transits from stellar magnetically-driven ... More
Temporal evolution and correlations of optical activity indicators measured in Sun-as-a-star observationsJun 07 2019(Abridged) We perform a detailed study of the main optical activity indicators (Ca II H & K, Balmer lines, Na I D$_{\rm 1}$ D$_{\rm 2}$, and He I D$_{\rm 3}$) measured for the Sun using the data provided by the HARPS-N solar-telescope feed at the Telescopio ... More
Synergy between professional and amateur astronomersJun 07 2019Since the CCD technique became financially reachable for amateur astronomers, they can cover topics of professional science. Mainly in the time-domain astronomy, such as variable star research, their help is invaluable. We focus on cooperation between ... More
Self-induced Scattering of Strahl Electrons in the Solar WindJun 06 2019We investigate the scattering of strahl electrons by micro-instabilities as a mechanism for creating the electron halo in the solar wind. We develop a mathematical framework for the description of electron-driven micro-instabilities and discuss the associated ... More
The B-Star Exoplanet Abundance Study: a co-moving 16-25 Mjup companion to the young binary system HIP 79098Jun 06 2019Wide low-mass substellar companions are known to be very rare among low-mass stars, but appear to become increasingly common with increasing stellar mass. However, B-type stars, which are the most massive stars within ~150 pc of the Sun, have not yet ... More
Multiple components of the Jhelum stellar streamJun 06 2019In simple models of the Milky Way, tidally disrupting satellites produce long and thin---nearly one-dimensional---stellar streams. Using astrometric data from the Gaia second data release and photometry from the Dark Energy Survey, we demonstrate that ... More
The role of atom tunneling in gas-phase reactions in planet-forming disksJun 06 2019This paper investigates the impact of the increased reaction rate constant due to tunneling effects on planet-forming disks. Our aim is to quantify the astrophysical implications of atom tunneling for simple molecules that are frequently used to infer ... More
Dust properties and star formation of about a thousand local galaxiesJun 06 2019[ABRIDGED] We derive the dust properties for 753 local galaxies and examine how these relate to some of their physical properties. We model their global dust-SEDs, treated statistically as an ensemble within a hierarchical Bayesian dust-SED modeling approach. ... More
Not Gone with the Wind: Planet Occurrence is Independent of Stellar Galactocentric VelocityJun 06 2019We demonstrate that planet occurrence does not depend on stellar galactocentric velocity in the Solar neighborhood. Using Gaia DR2 astrometry and radial velocity data, we calculate 3D galactocentric velocities for 197,090 Kepler field stars, 1647 of which ... More
Unusual plasma and particle signatures at Mars and STEREO-A related to CME-CME interactionJun 06 2019On July 25 2017 a multi-step Forbush decrease (FD) with the remarkable total amplitude of more than 15\% was observed by MSL/RAD at Mars. We find that these particle signatures are related to very pronounced plasma and magnetic field signatures detected ... More
Pulsar wind-heated accretion disk and the origin of modes in transitional millisecond pulsar PSR J1023+0038Jun 06 2019Transitional millisecond pulsars provide a unique set of observational data for understanding accretion at low rates onto magnetized neutron stars. In particular, PSR~J1023+0038 exhibits a remarkable bimodality of the X-ray luminosity (low and high modes), ... More
A photometric study of the high-mass-ratio contact binary AV PuppisJun 06 2019The multi-color photometric light curves for a contact binary AV Puppis (AV Pup) in $VR_cI_c$ bandpasses are presented, and they are analyzed by using of the 2013 version of the Wilson-Devinney (W-D) code. The solutions suggest that AV Pup is a peculiar ... More
Entropy Rain: Dilution and Compression of Thermals in Stratified DomainsJun 05 2019Large-scale convective flows called giant cells were once thought to transport the Sun's luminosity in the solar convection zone, but recent observations have called their existence into question. In place of large-scale flows, some authors have suggested ... More
The formation and dissipation of current sheets and shocks due to compressive waves in a stratified atmosphere containing a magnetic nullJun 05 2019We study the propagation and dissipation of magnetohydrodynamic waves in a set of numerical models that each include a solar--like stratified atmosphere and a magnetic field with a null point. All simulations have the same magnetic field configuration ... More
Microlensing optical depth and event rate toward the Galactic bulge from eight years of OGLE-IV observationsJun 05 2019The number and properties of observed gravitational microlensing events depend on the distribution and kinematics of stars and other compact objects along the line of sight. In particular, precise measurements of the microlensing optical depth and event ... More
Angular momentum in bipolar outflows: dynamical evolutionary modelJun 05 2019We model molecular outflows produced by the time dependent interaction between a stellar wind and a rotating cloud envelope in gravitational collapse, studied by Ulrich. We consider spherical and anisotropic stellar winds. We assume that the bipolar outflow ... More
Cold Debris Disks as Strategic Targets for the 2020sJun 05 2019Cold debris disks (T$<$200 K) are analogues to the dust in the Solar System's Kuiper belt--dust generated from the evaporation and collision of minor bodies perturbed by planets, our Sun, and the local interstellar medium. Scattered light from debris ... More
Constraining the properties of HD 206893 B. A combination of radial velocity, direct imaging, and astrometry dataJun 05 2019High contrast imaging enables the determination of orbital parameters for substellar companions (planets, brown dwarfs) from the observed relative astrometry and the estimation of model and age-dependent masses from their observed magnitudes or spectra. ... More
Constraining the properties of HD 206893 B. A combination of radial velocity, direct imaging, and astrometry dataJun 05 2019Jun 07 2019High contrast imaging enables the determination of orbital parameters for substellar companions (planets, brown dwarfs) from the observed relative astrometry and the estimation of model and age-dependent masses from their observed magnitudes or spectra. ... More
The eccentric behaviour of windy binary starsJun 05 2019Carbon-enhanced metal-poor stars, CH stars and barium stars, among other classes of chemically peculiar stars, are thought to be products of the interaction of low- and intermediate-mass binaries which occurred when the most evolved star was in the asymptotic ... More
ROAD and K2 photometry of V348 Sgr: probing the pulsation dust connectionJun 05 2019V348 Sgr is simultaneously an active hot R Coronae Borealis (RCB) variable, a peculiar extreme helium star, and the hydrogen-deficient central star of a planetary nebula. Explaining the RCB-type variability has been difficult since the star spends much ... More
On the ALMA observability of nascent massive multiple systemsJun 05 2019Massive young stellar object (MYSOs) form during the collapse of high-mass pre-stellar cores, where infalling molecular material is accreted through a centrifugally-balanced accretion disc that is subject to efficient gravitational instabilities. In the ... More
Amplitudes and energy fluxes of simulated decayless kink oscillationsJun 05 2019Recent observations with the Atmospheric Imaging Assembly (AIA) instrument on the SDO spacecraft have revealed the existence of decayless coronal kink oscillations. These transverse oscillations are not connected to any external phenomena like flares ... More
Small Planets in the Galactic Context: Host Star Kinematics, Iron, and $α$ Element EnhancementJun 05 2019We explored the occurrence rate of small close-in planets among $\textit{Kepler}$ target stars as a function of the iron abundance and the stellar total velocity $V_\mathrm{tot}$. We estimated the occurrence rate of those planets by combining information ... More
The Observational Evidence for the Internal Excitation of Sunspot Oscillations Inferred from the Fe I 5435 A LineJun 05 2019The umbral oscillations of velocity are commonly observed in the chromosphere of a sunspot. Their sources are considered to be either the external p-mode driving or the internal excitation by magnetoconvection. Even though the possibility of the p-mode ... More
Observational signatures of outbursting protostars -- II: Exploring a wide range of eruptive protostarsJun 05 2019Young stars exhibit variability due to changes in the gas accretion rate onto them, an effect that should be quite significant in the early stages of their formation. As protostars are embedded within their natal cloud, this variability may only be inferred ... More
Observational signatures of outbursting protostars - I: From hydrodynamic simulations to observationsJun 05 2019Accretion onto protostars may occur in sharp bursts. Accretion bursts during the embedded phase of young protostars are probably most intense, but can only be inferred indirectly through long-wavelength observations. We perform radiative transfer calculations ... More
NuGrid stellar data set - III. Updated low-mass AGB models and s-process nucleosynthesis with metallicities Z=0.01, Z=0.02 and Z=0.03Jun 05 2019The production of the neutron-capture isotopes beyond iron that we observe today in the solar system is the result of the combined contribution of the r-process, the s- process and possibly the i-process. Low-mass AGB (2 < M/Msun < 3) and massive (M >10 ... More
Galaxy simulation with the evolution of grain size distributionJun 05 2019We compute the evolution of interstellar dust in a hydrodynamic simulation of an isolated disc galaxy. We newly implement the evolution of full grain size distribution by sampling 32 grid points on the axis of the grain radius. We solve it consistently ... More
Study of Eclipsing Binary and Multiple Systems in OB Associations V: MQ Cen in Crux OB1Jun 05 2019The early-type massive binary MQ Cen (P$_{orb}$=3.7 d) has been investigated by means of high-resolution ($R\sim48\,000$) spectral analysis and multi-band (Johnson $BVRI$ and Str\"{o}mgren $vby$) light curve modeling. The physical parameters of the components ... More
The early life of millisecond magnetarsJun 05 2019Some neutron stars may be born spinning fast and with strong magnetic fields---the so-called \emph{millisecond magnetars}. It is important to understand how a star's magnetic axis moves with respect to the spin axis in the star's early life, as this effects ... More
Two-fluid numerical simulations of the origin of the fast solar windJun 05 2019With the use of our JOANNA code, which solves radiative equations for ion + electron and neutralfluids, we perform realistic 2.5D numerical simulations of plasma outflows associated with the solargranulation. These outflows exhibit physical quantities ... More
Two-fluid numerical simulations of the origin of the fast solar windJun 05 2019Jun 06 2019With the use of our JOANNA code, which solves radiative equations for ion + electron and neutral fluids, we perform realistic 2.5D numerical simulations of plasma outflows associated with the solar granulation. These outflows exhibit physical quantities ... More
The Evolution of the Interstellar Medium in Post-Starburst GalaxiesJun 05 2019We derive dust masses ($M_{\rm dust}$) from the spectral energy distributions of 58 post-starburst galaxies (PSBs). There is an anticorrelation between specific dust mass ($M_{\rm dust}$/$M_{\star}$) and the time elapsed since the starburst ended, indicating ... More
The Role of Energy Diffusion in the Deposition of Energetic Electron Energy in Solar and Stellar FlaresJun 05 2019During solar flares, a large fraction of the released magnetic energy is carried by energetic electrons that transfer and deposit energy in the Sun's atmosphere. Electron transport is often approximated by a cold thick-target model (CTTM), assuming that ... More