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Does HL Tau Disk Polarization in ALMA Band 3 Come from Radiatively Aligned Grains?: Disk polarization in (sub)millimeter dust continuum is a rapidly growing field in the ALMA era. It opens up the exciting possibility of detecting and characterizing magnetic fields and grain growth in disks around young stellar object...
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Wide-angle protostellar outflows driven by narrow jets in stratified cores: Most simulations of outflow feedback on star formation are based on the assumption that outflows are driven by a wide angle "X-wind," rather than a narrow jet. However, the arguments initially raised against pure jet-driven flows were based o...
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Models for velocity decrease in HH34: The conservation of the energy flux in turbulent jets that propagate in the interstellar medium (ISM) allows us to deduce the law of motion when an inverse power law decrease of density is considered. The back-reaction that is caused by the radiative losses for the trajectory is ev...
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Cool dwarfs stars from the Torino Observatory Parallax Program: We investigate and parameterise high proper motion red stars in the Torino Observatory Parallax Program. Observations of 27 objects were made over the period 1994 - 2001 on the 1.05m Torino telescope. The trigonometric parallaxes and proper motions were de...
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Realistic model atmosphere and revised abundances of the coolest Ap star HD101065: Among the known Ap stars, HD101065 is probably one of the most interesting objects, demonstrating very rich spectra of rare-earth elements (REE). Strongly peculiar photometric parameters of this star that can not be fully reproduced by...
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Contributions of structural variations to the asymptotic mixed-mode coupling Factor in red giant stars: The advent of ultra-precise photometry space missions enable the possibility of investigating stellar interior with mixed modes. The structural variations induced by the discontinuity of the chemical composition le...
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Frequency analysis of Delta Scuti stars towards the Galactic bulge: We have performed a frequency analysis of 10,092 Delta Scuti-type stars detected in the fourth phase of the Optical Gravitational Lensing Experiment (OGLE) towards the Galactic bulge, which is the most numerous homogeneous sample of Delta Scuti stars o...
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The M Supergiant High Mass X-Ray Binary 4U 1954+31: The X-ray binary 4U 1954+31 has been classified as a Low Mass X-ray Binary (LMXB) containing a M giant and a neutron star (NS). It has also been included in the rare class of X-ray symbiotic binaries (SyXB). The Gaia parallax, infrared colors, spectral type, abundance...
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The Strength and Variability of the Helium 10830 Å Triplet in Young Stars, with Implications for Exosphere Detection: Young exoplanets trace planetary evolution, particularly the atmospheric mass loss that is most dynamic in youth. However, the high activity level of young stars can mask or mimic the spectroscopic si...
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Constraining modified gravity from tidal phenomena in binary stars: In beyond-Horndeski theories of gravity, the Vainshtein screening mechanism might only be partially effective inside stellar objects. This results in a modification of the pressure balance equation inside stars, often characterized by a single paramete...
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Eleven Exoplanet Host Star Angular Diameters from the CHARA Array: We directly measured the angular diameters for 11 exoplanet host stars using Georgia State University's CHARA Array interferometer and calculated their linear radii and effective temperatures. The sample tends towards evolving or evolved stars and inclu...
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Tests of Sunspot Number Sequences: 2. Using Geomagnetic and Auroral Data: We compare four sunspot-number data sequences against geomagnetic and terrestrial auroral observations. The comparisons are made for the original SIDC composite of Wolf-Zurich-International sunspot number [$R_{ISNv1}$], the group sunspot number [...
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Population Synthesis of Black Hole Binaries with Normal-Star Companions: I. Detached Systems: Optical observations of normal-stars in binary systems with massive unseen objects have been proposed to search for candidate black holes (BHs) and provide a direct measurement of their dynamical masses. In this paper, we ha...
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The Gaia-ESO Survey. Mg-Al anti-correlation in iDR4 globular clusters: We use Gaia-ESO Survey iDR4 data to explore the Mg-Al anti-correlation in globular clusters, that were observed as calibrators, as a demonstration of the quality of Gaia-ESO Survey data and analysis. The results compare well with the available liter...
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SST/CRISP Observations of Convective Flows in a Sunspot Penumbra: Context. Recent discoveries of intensity correlated downflows in the interior of a sunspot penumbra provide direct evidence for overturning convection, adding to earlier strong indications of convection from filament dynamics observed far from solar disk...
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Presupernova neutrinos: realistic emissivities from stellar evolution: We present a new calculation of neutrino emissivities and energy spectra from a massive star going through the advanced stages of nuclear burning (presupernova) in the months before becoming a supernova. The contributions from beta decay and electro...
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A solar flare disturbing a light wall above a sunspot light bridge: With the high-resolution data from the Interface Region Imaging Spectrograph, we detect a light wall above a sunspot light bridge in the NOAA active region (AR) 12403. In the 1330 A slit-jaw images, the light wall is brighter than the ambient areas whi...
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On the nature of the WO3 star DR1 in IC 1613: We present the results of a quantitative spectroscopic analysis of the oxygen-sequence Wolf- Rayet star DR1 in the low-metallicity galaxy IC 1613. Our models suggest that the strong oxygen emission lines are the result of the high temperature of this WO3 star and do not nec...
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Spectro-interferometry of the Be star delta Sco: Near-Infrared Continuum and Gas Emission Region Sizes in 2007: We present near-infrared H and K-band spectro-interferometric observations of the gaseous disk around the primary Be star in the delta Sco binary system, obtained in 2007 (between periastron passages in 200...
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Nonequilibrium ionization and ambipolar diffusion in solar magnetic flux emergence processes: Magnetic flux emergence has been shown to be a key mechanism for unleashing a wide variety of solar phenomena. However, there are still open questions concerning the rise of the magnetized plasma through the atmosphere, main...
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Corona-Australis DANCe. I. Revisiting the census of stars with Gaia-DR2 data: Corona-Australis is one of the nearest regions to the Sun with recent and ongoing star formation, but the current picture of its stellar (and substellar) content is not complete yet. We take advantage of the second data release of the Gaia ...
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Cross and magnetic helicity in the outer heliosphere from Voyager 2 observations: Plasma velocity and magnetic field measurements from the Voyager 2 mission are used to study solar wind turbulence in the slow solar wind at two different heliocentric distances, 5 and 29 astronomical units, sufficiently far apart to pr...
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An `Analytic Dynamical Magnetosphere' formalism for X-ray and optical emission from slowly rotating magnetic massive stars: Slowly rotating magnetic massive stars develop "dynamical magnetospheres" (DM's), characterized by trapping of stellar wind outflow in closed magnetic loops, shock heating from collision of the ...
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A Possible Period for the K-band Brightening Episodes of GX 17+2: The low mass X-ray binary and Z source GX 17+2 undergoes infrared K-band brightening episodes of at least 3.5 magnitudes. The source of these episodes is not known. Prior published K-band magnitudes and new K-band measurements acquired between 2006 and 2...
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An Incipient Debris Disk in the Chamaeleon I Cloud: The point at which a protoplanetary disk becomes a debris disk is difficult to identify. To better understand this, here we study the $\sim$40~AU separation binary T~54 in the Chamaeleon I cloud. We derive a K5 spectral type for T~54~A (which dominates the emission of...
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Massive star-formation toward G28.87+0.07 (IRAS 18411-0338) investigated by means of maser kinematics and radio to infrared, continuum observations: We used the Very Long Baseline Array (VLBA) and the European VLBI Network (EVN) to perform phase-referenced VLBI observations of the three most powerful maser transition...
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Deriving photospheric parameters and elemental abundances for a sample of stars showing the FIP effect: One puzzling question in solar physics is the difference between elemental abundances in the photosphere and the corona. Elements with low first ionization potential (FIP) can be overabundant in the corona compared...
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Pre-flare activity and magnetic reconnection during the evolutionary stages of energy release in a solar eruptive flare: In this paper, we present a multi-wavelength analysis of an eruptive white-light M3.2 flare which occurred in active region NOAA 10486 on November 1, 2003. Excellent set of high resolution observat...
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Magnetohydrodynamic wave mode identification in circular and elliptical sunspot umbrae: evidence for high order modes: In this paper we provide clear direct evidence of multiple concurrent higher order magnetohydrodynamic (MHD) modes in circular and elliptical sunspots by applying both Proper Orthogonal Decomposition...
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The frequency of large variations in the near-infrared fluxes of T Tauri stars: Variability is a characteristic feature of young stellar objects (YSOs) and could contribute to the large scatter observed in HR diagrams for star forming regions. For typical YSOs, however, the long-term effects of variability are poorly...
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A flash of polarized optical light points to an aspherical "cow": The astronomical transient AT2018cow is the closest example of the new class of luminous, fast blue optical transients (FBOTs). Liverpool Telescope RINGO3 observations of AT2018cow are reported here, which constitute the earliest polarimetric observation...
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Correlation Analysis of Mode Frequencies with Activity Proxies at Different Phases of the Solar Cycle: We analyze intermediate degree p- and f-mode eigenfrequencies measured by GONG and MDI/SOHO for a complete solar cycle to study their correlation with solar activity. We demonstrate that the frequencies do vary line...
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Theoretical seismology in 3D : nonlinear simulations of internal gravity waves in solar-like stars: Internal gravity waves (hereafter IGWs) are studied for their impact on the angular momentum transport in stellar radiation zones and the information they provide about the structure and dynamics of deep stellar interi...
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High-resolution spectroscopic view of planet formation sites: Theories of planet formation predict the birth of giant planets in the inner, dense, and gas-rich regions of the circumstellar disks around young stars. These are the regions from which strong CO emission is expected. Observations have so far been unable to ...
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Characterising face-on accretion onto and the subsequent contraction of protoplanetary discs: Observations indicate that stars generally lose their protoplanetary discs on a timescale of about 5 Myr. Which mechanisms are responsible for the disc dissipation is still debated. Here we investigate the movement through a...
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Period and amplitude variations in post-common-envelope eclipsing binaries observed with SuperWASP: Period or amplitude variations in eclipsing binaries may reveal the presence of additional massive bodies in the system, such as circumbinary planets. Here, we have studied twelve previously-known eclipsing post-common...
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CoBiToM Project -- II: Evolution of contact binary systems close to the orbital period cut-off: Ultra-short orbital period contact binaries (Porb < 0.26 d) host some of the smallest and least massive stars. These systems are faint and rare, and it is believed that they have reached a contact configuration after sever...
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Nearby Young, Active, Late-type Dwarfs in Gaia's First Data Release: The Galex Nearby Young Star Survey (GALNYSS) has yielded a sample of $\sim$2000 UV-selected objects that are candidate nearby ($D \stackrel{<}{\sim}$150 pc), young (age $\sim$10--100 Myr), late-type stars. Here, we evaluate the distances and ages of t...
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Corrected Weight Functions for Stellar Oscillation Eigenfrequencies: Kawaler et al. (1985) present a variational expression for the eigenfrequencies associated with stellar oscillations. We highlight and correct a typographical error in the weight functions appearing in these expressions, and validate the correction nu...
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Stellar atmospheres, atmospheric extension and fundamental parameters: weighing stars using the stellar mass index: One of the great challenges in understanding stars is measuring their masses. The best methods for measuring stellar masses include binary interaction, asteroseismology and stellar evolution models, but...
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Isochronal age scale of young moving groups in the solar neighbourhood: We present a self-consistent, absolute isochronal age scale for young (< 200 Myr), nearby (< 100 pc) moving groups, which is consistent with recent lithium depletion boundary ages for both the Beta Pic and Tucana-Horologium moving groups. This age ...
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Understanding the origin of the magnetic field morphology in the wide-binary protostellar system BHR 71: We present 1.3 mm ALMA observations of polarized dust emission toward the wide-binary protostellar system BHR 71 IRS1 and IRS2. IRS1 features what appears to be a natal, hourglass-shaped magnetic field. In contras...
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A 9-Month Hubble Space Telescope Near-UV Survey of M87. I. Light and Color Curves of 94 Novae, and a Re-determination of the Nova Rate: M87 has been monitored with a cadence of 5 days over a 9 month-long span through the near-ultraviolet (NUV:F275W) and optical (F606W) filters of the Wide Field Camera 3 (WFC3) of the...
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Atomic diffusion in solar-like stars with MESA. Comparison with the Montreal/Montpellier and CESTAM stellar evolution codes: The stellar evolution code Modules for Experiments in Stellar Astrophysics (MESA) is public and is widely used by the community. It includes the possibility of taking several non-standard proce...
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Spectroscopic and Photometric Study of the Asymptotic Giant Branch Star T Cephei: Spectroscopy and photometry of the Asymptotic Giant Branch star T Cephei were recorded concurrently on 36 nights during its 387 day pulsation cycle in 2022. Photometry was used to calibrate all spectra in absolute flux. We report on the...
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Short term period variable stars observed at OAUNI: We present the first scientific results of the program on short term period variable stars observed using the OAUNI facility at the peruvian Andes. These results include good quality light curves of delta Scuti stars, rapidly oscillating stars along with eclipsing and...
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Wide-angle protostellar outflows driven by narrow jets in stratified cores: Most simulations of outflow feedback on star formation are based on the assumption that outflows are driven by a wide angle "X-wind," rather than a narrow jet. However, the arguments initially raised against pure jet-driven flows were based o...
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Long-term variability of T Tauri stars using WASP: We present a reference study of the long-term optical variability of young stars using data from the WASP project. Our primary sample is a group of well-studied classical T Tauri stars (CTTS), mostly in Taurus-Auriga. WASP lightcurves cover timescales up to 7 years and...
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Magnetic OB[A] Stars with TESS: probing their Evolutionary and Rotational properties -- The MOBSTER Collaboration: In this contribution, we present the MOBSTER Collaboration, a large community effort to leverage high-precision photometry from the Transiting Exoplanet Survey Satellite (\textit{TESS}) in order to chara...
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Understanding the origin of the [OI] low-velocity component from T Tauri stars: The formation time, masses, and location of planets are strongly impacted by the physical mechanisms that disperse protoplanetary disks and the timescale over which protoplanetary material is cleared out. Accretion of matter onto the cent...
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Shearing box simulations in the Rayleigh unstable regime: We study the stability properties of Rayleigh unstable flows both in the purely hydrodynamic and magnetohydrodynamic (MHD) regimes for two different values of the shear $q=2.1, 4.2$ ($q = - d\ln\Omega / d\ln r$) and compare it with the Keplerian case $q=1.5$. We...
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Solar supergranular fractal dimension dependence on the Solar cycle phase: We study the complexity of the supergranular network through fractal dimension by using Ca II K digitized data archive obtained from Kodaikanal solar observatory. The data consists of 326 visually selected supergranular cells spread across the...
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FUSE, STIS, and Keck spectroscopic analysis of the UV-bright star vZ 1128 in M3 (NGC 5272): We present a spectral analysis of the UV-bright star vZ 1128 in M3 based on observations with the Far Ultraviolet Spectroscopic Explorer (FUSE), the Space Telescope Imaging Spectrograph (STIS), and the Keck HIRES echelle spect...
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Discovery of electron cyclotron MASER emission from the magnetic Bp star HD 133880 with the Giant Metrewave Radio Telescope: We report the discovery of coherent radio emission from the young, rapidly-rotating magnetic Bp star HD 133880 at a frequency of 610 MHz with the Giant Metrewave Radio Telescope (GMRT). This is...
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Constraining the neutrino magnetic dipole moment from white dwarf pulsations: Pulsating white dwarf stars can be used as astrophysical laboratories to constrain the properties of weakly interacting particles. Comparing the cooling rates of these stars with the expected values from theoretical models allows us to sear...
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Generalized multi-polytropic Rankine-Hugoniot relations and the entropy condition: The study aims at a derivation of generalized \RH relations, especially that for the entropy, for the case of different upstream/downstream polytropic indices and their implications. We discuss the solar/stellar wind interaction with t...
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Search for systemic mass loss in Algols with bow shocks: Aims. Various studies indicate that interacting binary stars of Algol type evolve non-conservatively. However, direct detections of systemic mass loss in Algols have been scarce so far. We study the systemic mass loss in Algols by looking for the presence of infr...
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The Factory and The Beehive I. Rotation Periods For Low-Mass Stars in Praesepe: Stellar rotation periods measured from single-age populations are critical for investigating how stellar angular momentum content evolves over time, how that evolution depends on mass, and how rotation influences the stellar dynamo and th...
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OGLE-2016-BLG-1003: First Resolved Caustic-crossing Binary-source Event Discovered by Second-generation Microlensing Surveys: We report the analysis of the first resolved caustic-crossing binary-source microlensing event OGLE-2016-BLG-1003. The event is densely covered by the round-the-clock observations of three sur...
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A Study of the Orbital Periods of Deeply Eclipsing SW Sextantis Stars: Results are presented of a five-year project to study the orbital periods of eighteen deeply eclipsing novalike cataclysmic variables, collectively known as SW Sextantis stars, by combining new measurements of eclipse times with published measuremen...
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Conditions for Photospherically Driven Alfvenic Oscillations to Heat the Solar Chromosphere by Pedersen Current Dissipation: A magnetohydrodynamic model that includes a complete electrical conductivity tensor is used to estimate conditions for photospherically driven, linear, non-plane Alfvenic oscillations extending...
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Precision southern hemisphere VLBI pulsar astrometry II: Measurement of seven parallaxes: Accurate measurement of pulsar distances via astrometry using very long baseline interferometry enables the improvement of Galactic electron density distribution models, improving distance estimates for the vast majority of puls...
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Estimating Stellar Atmospheric Parameters by Automated Methods Using SSLs: Libraries of stellar spectra, such as ELODIE (Prugniel & Soubiran 2001), CFLIB (Valdes et al. 2004), or MILES (S\'anchez-Bl\'azquez et al. 2006), are used for a variety of applications, and especially in modelling stellar populations (e. g. Le...
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Validation of the Exoplanet Kepler-21b using PAVO/CHARA Long-Baseline Interferometry: We present long-baseline interferometry of the Kepler exoplanet host star HD179070 (Kepler-21) using the PAVO beam combiner at the CHARA Array. The visibility data are consistent with a single star and exclude stellar companions at ...
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Accretion process, magnetic fields, and apsidal motion in the pre-main sequence binary DQ Tau: Classical T Tauri stars (CTTSs) are young stellar objects that accrete materials from their accretion disc influenced by their strong magnetic field. The magnetic pressure truncates the disc at a few stellar radii and force...
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Modelling the occurrence of grand minima in sun-like stars using a dynamo model: In this work, we have studied the variability and frequency of occurrence of the grand minima using kinematic dynamo models of one solar mass star with different rotation rates and depths of convection zones. We specify the large-scale f...
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Magnetic field and prominences of the young, solar-like, ultra-rapid rotator V530 Per: We investigate signatures of magnetic fields and activity at the surface and in the prominence system of the ultra-rapid rotator V530 Per, a G-type solar-like member of the young open cluster $\alpha$~Persei. This object has a rota...
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An Observational Perspective of Transitional Disks: Transitional disks are objects whose inner disk regions have undergone substantial clearing. The Spitzer Space Telescope produced detailed spectral energy distributions (SEDs) of transitional disks that allowed us to infer their radial dust disk structure in some deta...
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Extension and validation of the pendulum model for longitudinal solar prominence oscillations: Longitudinal oscillations in prominences are common phenomena on the Sun. These oscillations can be used to infer the geometry and intensity of the filament magnetic field. Previous theoretical studies of longitudinal oscil...
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Destabilization of a Solar Prominence/Filament Field System by a Series of Eight Homologous Eruptive Flares: Homologous flares are flares that occur repetitively in the same active region, with similar structure and morphology. A series of at least eight homologous flares occurred in active region NOAA 11237 over 16 ...
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Generalized three body problem and the instability of the core-halo objects in binary systems: Goal of the presented research is to construct simplified model of the core-halo structures in binary systems. Examples are provided by Thorne-Zytkov objects, hot Jupiters, protoplanets with large moons, red supergiants in ...
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The Clusters AgeS Experiment (CASE): Variable Stars in the Globular Cluster M4: Based on over 3000 BV images of M4 collected in years 1995-2009 we obtain light curves of 22 variables, 10 of which are newly detected objects. We identify four detached eclipsing binaries and eight contact binaries. Accurate periods are ...
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Sunspot rotation. II. Effects of varying the field strength and twist of an emerging flux tube: Context. Observations of flux emergence indicate that rotational velocities may develop within sunspots. However, the dependence of this rotation on sub-photospheric field strength and twist remains largely unknown. Aims...
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FIP Bias Evolution in a Decaying Active Region: Solar coronal plasma composition is typically characterized by first ionization potential (FIP) bias. Using spectra obtained by Hinode's EUV Imaging Spectrometer (EIS) instrument, we present a series of large-scale, spatially resolved composition maps of active region (AR...
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The Branchings of the Main s-process: Their Sensitivity to alpha-induced Reactions on 13C and 22Ne and to the Uncertainties of the Nuclear Network: This paper provides a detailed analysis of the main component of the slow neutron capture process (the s-process), which accounts for the solar abundances of half of the ...
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Toward understanding the early stages of an impulsively accelerated coronal mass ejection: The expanding magnetic flux in coronal mass ejections (CMEs) often forms a cavity. A spherical model is simultaneously fit to STEREO EUVI and COR1 data of an impulsively accelerated CME on 25 March 2008, which displays a well-d...
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Radio Measurements of the stellar proper motions in the core of the Orion Nebula Cluster: Using multi-epoch VLA observations, covering a time baseline of 29.1 years, we have measured the proper motions of 88 young stars with compact radio emission in the core of the Orion Nebula Cluster (ONC) and the neighboring BN/K...
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Horizontal flow fields observed in Hinode G-band images. I. Methods: Context: The interaction of plasma motions and magnetic fields is an important mechanism, which drives solar activity in all its facets. For example, photospheric flows are responsible for the advection of magnetic flux, the redistribution of flux dur...
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From Protoplanetary Disks to Extrasolar Planets: Understanding the Life Cycle of Circumstellar Gas with Ultraviolet Spectroscopy: Few scientific discoveries have captured the public imagination like the explosion of exoplanetary science during the past two decades. This work has fundamentally changed our picture of E...
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WR 63: A multiple system (O+O)+WR ?: The spectrum of the Wolf-Rayet (WR) star WR 63 contains spectral lines of two different O stars that show regular radial velocity (RV) variations with amplitudes of ~160 and ~225 km/s on a ~4.03 d period. The light-curve shows two narrow eclipses that are 0.2 mag deep on the same pe...
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A deep catalogue of classical Be stars in the direction of the Perseus Arm: spectral types and interstellar reddenings: We present a catalogue of 247 photometrically and spectroscopically confirmed fainter classical Be stars (13 < r < 16) in the direction of the Perseus Arm of the Milky Way (-1 < b < +4, 120 < l < 14...
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Microlensing Binaries Discovered through High-Magnification Channel: Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of 8 binary lensing events detected through the channel of high-magnification events during t...
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Hubble Space Telescope reveals multiple Sub-Giant Branch in eight Globular Clusters: In the last few years many globular clusters (GCs) have revealed complex color-magnitude diagrams, with the presence of multiple main sequences (MSs), broaden or multiple sub-giant branches (SGBs) and MS turn offs, and broad or split...
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Evidence of Electron Acceleration around the Reconnection X-point in a Solar Flare: Particle acceleration is one of the most significant features that are ubiquitous among space and cosmic plasmas. It is most prominent during flares in the case of the Sun, with which huge amount of electromagnetic radiation and high-...
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High resolution soft X-ray spectroscopy and the quest for the hot (5-10 MK) plasma in solar active regions: We discuss the diagnostics available to study the 5-10 MK plasma in the solar corona, which is key to understanding the heating in the cores of solar active regions. We present several simulated spectra, and sh...
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Cepheid Abundances: Multiphase Results and Spatial Gradients: Parameters and abundances have been derived for 435 Cepheids based on an analysis of 1127 spectra. Results from five or more phases are available for 52 of the program stars. The latter set of stars span periods between 1.5 and 68 days. The parameters and ab...
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Measurements of Non-Thermal Line Widths in Solar Active Regions: Spectral line widths are often observed to be larger than can be accounted for by thermal and instrumental broadening alone. This excess broadening is a key observational constraint for both nanoflare and wave dissipation models of coronal heating. Here w...
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Space, time and velocity association of successive coronal mass ejections: Our aim is to investigate the possible physical association between consecutive coronal mass ejections (CMEs). Through a statistical study of the main characteristics of 27761 CMEs observed by SOHO/LASCO during the past 20 years. We found the ...
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First Keck Nulling Observations of a Young Stellar Object: Probing the Circumstellar Environment of the Herbig Ae star MWC 325: We present the first N-band nulling plus K- and L-band V2 observations of a young stellar object, MWC325, taken with the 85 m baseline Keck Interferometer. The Keck nuller was designed for t...
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Perpendicular Diffusion of Energetic Particles in Collisionless Plasmas: A fundamental problem in plasma and astrophysics is the interaction between energetic particles and magnetized plasmas. In the current paper we focus on particle diffusion across the guide magnetic field. It is shown that the perpendicular diffusi...
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Solar Flare Prediction and Feature Selection using Light Gradient Boosting Machine Algorithm: Solar flares are among the most severe space weather phenomena, and they have the capacity to generate radiation storms and radio disruptions on Earth. The accurate prediction of solar flare events remains a significant chal...
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Penumbral micro-jets at high spatial and temporal resolution: Sunspot observations in chromospheric spectral lines have revealed the existence of short-lived linear bright transients, commonly referred to as penumbral micro-jets (PMJs). Details on the origin and physical nature of PMJs are to large extend still unkown....
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High-cadence spectroscopy of M-dwarfs. I. Analysis of systematic effects in HARPS-N line profile measurements on the bright binary GJ 725A+B: Understanding the sources of instrumental systematic noise is a must to improve the design of future spectrographs. In this study, we alternated observations of the well-suited...
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Statistical Analysis of the Horizontal Divergent Flow in Emerging Solar Active Regions: Solar active regions (ARs) are thought to be formed by magnetic fields from the convection zone. Our flux emergence simulations revealed that a strong horizontal divergent flow (HDF) of unmagnetized plasma appears at the photosphe...
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The inner environment of protoplanetary disks with near infrared spectro-interferometry: In this paper, I review how optical spectro-interferometry has become a particularly well suited technique to study the close environment of young stars, by spatially resolving both their IR continuum and line emission regions. I...
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The rotation rate of solar active and ephemeral regions -- II. Temporal variations of the rotation rates: Systematic studies of the rotation rate of sunspot groups using white-light images yield controversial results on the variations of the rotation rate: sunspot groups were found to either accelerate or decelerate ...
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A new ephemeris and an orbital solution of ε Aurigae: We collected rich series of RV measurements covering last 110 years and photometric observations from the past 6 primary eclipses, complemented them by our new observations and derived a new precise ephemeris and an orbital solution of epsilon Aur.
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Flux-Rope Twist in Eruptive Flares and CMEs: due to Zipper and Main-Phase Reconnection: The nature of three-dimensional reconnection when a twisted flux tube erupts during an eruptive flare or coronal mass ejection is considered. The reconnection has two phases: first of all, 3D "zipper reconnection" propagates along...
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The nature of Elsässer variables in compressible MHD: The Els\"{a}sser variables are often used in studies of plasma turbulence, in helping differentiate between MHD waves propagating parallel or anti-parallel to the main magnetic field. While for pure Alfv\'en waves in a homogeneous plasma the method is strictly valid...
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Summary of IAU GA SpS5 - I. Obscured and distant clusters: This first part of Special Session 5 explored the current status of infrared-based observations of obscured and distant stellar clusters in the Milky Way galaxy. Recent infrared surveys, either serendipitously or using targeted searches, have uncovered a rich p...
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