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Discovery of 34 low-mass comoving systems using NOIRLab Source Catalog DR2: We present the discovery of 34 comoving systems containing an ultra-cool dwarf found by means of the NOIRLab Source Catalog (NSC) DR2. NSC's angular resolution of $\sim$1" allows for the detection of small separation binaries with significant...
astro-ph_SR
Miras around the Galactic Center: We report results of our near-IR survey for variables in a field of view of 20 arcmin by 30 arcmin towards the Galactic Center (GC), where we detected 1364 long-period variables. We have established a method for the simultaneous estimation of distances and extinctions using the period-...
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Flickering in AGB stars: Probing the nature of accreting companions: Binary companions to asymptotic giant branch (AGB) stars are an important aspect of their evolution. Few AGB companions have been detected, and in most cases it is difficult to distinguish between main-sequence and white dwarf companions. Detection of...
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MHD waves in sunspots: The review addresses the spatial frequency morphology of sources of sunspot oscillations and waves, including their localization, size, oscillation periods, height localization with the mechanism of cut-off frequency that forms the observed emission variability. Dynamic of sunspot wave processes,...
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Simultaneous Multiwavelength Observations of Magnetic Activity in Ultracool Dwarfs. IV. The Active, Young Binary NLTT 33370 AB (=2MASS J13142039+1320011): We present multi-epoch simultaneous radio, optical, H{\alpha}, UV, and X-ray observations of the active, young, low-mass binary NLTT 33370 AB (blended spectral t...
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6.7 GHz variability characteristics of new periodic methanol maser sources: Discovery of periodic maser emission was an unexpected result from monitoring observations of methanol transitions in high-mass young stellar objects. We report on the detection of five new periodic sources from a monitoring program with the ...
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LMC Blue Supergiant Stars and the Calibration of the Flux-weighted Gravity--Luminosity Relationship: High quality spectra of 90 blue supergiant stars in the Large Magellanic Cloud are analyzed with respect to effective temperature, gravity, metallicity, reddening, extinction and extinction law. An average metallicity...
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Two circumstellar nebulae discovered with the Wide-field Infrared Survey Explorer and their massive central stars: We report the discovery of two mid-infrared nebulae in the northern hemisphere with the Wide-field Infrared Survey Explorer and the results of optical spectroscopy of their central stars, BD+60 2668 (com...
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High-precision abundances of Sc, Mn, Cu, and Ba in solar twins. Trends of element ratios with stellar age: A previous study of correlations between element abundance ratios, [X/Fe], and ages of solar twin stars is extended to include Sc, Mn, Cu, and Ba. HARPS spectra with S/N > 600 are used to derive very precise (+/...
astro-ph_SR
The DDO Close Binary Spectroscopic Program: The survey of radial velocity orbits for short period (P < 1 day), bright (V < 10, with a few fainter stars) conducted at the David Dunlap Observatory in the last 9 years before its closure in 2008 included 162 binaries and resulted in 150 SB2 orbits and 5 SB1 spectroscopic o...
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Measurement of the core-collapse progenitor mass distribution of the Small Magellanic Cloud: The physics of core-collapse (CC) supernovae (SNe) and how the explosions depend on progenitor properties are central questions in astronomy. For only a handful of SNe, the progenitor star has been identified in pre-explosion...
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Image patch analysis of sunspots and active regions. I. Intrinsic dimension and correlation analysis: The flare-productivity of an active region is observed to be related to its spatial complexity. Mount Wilson or McIntosh sunspot classifications measure such complexity but in a categorical way, and may therefore not...
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Close detached white dwarf + brown dwarf binaries: further evidence for low values of the common envelope efficiency: Common envelope evolution is a fundamental ingredient in our understanding of the formation of close binary stars containing compact objects which includes the progenitors of type Ia supernovae, short...
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Evolution of massive population III stars with rotation and magnetic fields: [Abridged] We present a new grid of massive population III star models including the effects of rotation on the stellar structure and chemical mixing, and magnetic torques for the transport of angular momentum. Based on the grid, we also pre...
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The Age and The Mass of The αHerculis Triple-Star System From A MESA Grid of rotating stars with 1.3 <= M/Msun <= 8.0: \alpha^1 Her is the second closest Asymptotic Giant Branch (AGB) star to the Sun, and the variable luminous M5 Ib-II member of a triple stellar system containing G8 III and A9 IV-V components. Howeve...
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Optical photometric GTC/OSIRIS observations of the young massive association Cygnus OB2: In order to fully understand the gravitational collapse of molecular clouds, the star formation process and the evolution of circumstellar disks, these phenomena must be studied in different Galactic environments with a range of ...
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Brightness of the Sun's small scale magnetic field: proximity effects: The net effect of the small scale magnetic field on the Sun's (bolometric) brightness is studied with realistic 3D MHD simulations. The direct effect of brightening within the magnetic field itself is consistent with measurements in high-resolution ...
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Block-induced complex structures building the flare-productive solar active region 12673: Solar active region (AR) 12673 produced 4 X-class, 27 M-class, and numerous lower class flares during its passage across the visible solar disk in September 2017. Our study is to answer the questions why this AR was so flare-pro...
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Properties of simulated sunspot umbral dots: Realistic 3D radiative MHD simulations reveal the magneto-convective processes underlying the formation of the photospheric fine structure of sunspots, including penumbral filaments and umbral dots. Here we provide results from a statistical analysis of simulated umbral dots...
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BANYAN. VII. A New Population of Young Substellar Candidate Members of Nearby Moving Groups from the BASS Survey: [Abbreviated] We present the results of a near-infrared (NIR) spectroscopic follow-up survey of 182 M4-L7 low-mass stars and brown dwarfs (BDs) from the BANYAN All-Sky Survey (BASS) for candidate members ...
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Radio emission as a stellar activity indicator: Radio observations of stars trace the plasma conditions and magnetic field properties of stellar magnetospheres and coronae. Depending on the plasma conditions at the emitter site, radio emission in the metre- and decimetre-wave bands is generated via different mechanisms...
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IC 4663: The first unambiguous [WN] Wolf-Rayet central star of a planetary nebula: We report on the serendipitous discovery of the first central star of a planetary nebula (PN) that mimics the helium- and nitrogen-rich WN sequence of massive Wolf-Rayet (WR) stars. The central star of IC 4663 (PN G346.2-08.2) is domin...
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Multi-epoch spectropolarimetry of SN 2009ip: direct evidence for aspherical circumstellar material: We present spectropolarimetry of SN 2009ip throughout the evolution of its 2012 explosion. During the initial 2012a phase, when the source spectrum exhibits broad P-Cygni lines, we measure a V-band polarization of P~0....
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Synthetic Light Curves for Born Again Events: Preliminary Results: The development of surveys which will be able to cover a large region of the sky several times per year will allow the massive detection of transient events taking place in timescales of years. In addition, the projected full digitalization of the Harva...
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Spectroscopic survey of Kepler stars. II. FIES/NOT observations of A- and F-type stars: We have analysed high-resolution spectra of 28 A and 22 F stars in the Kepler field, observed with the FIES spectrograph at the Nordic Optical Telescope. We provide spectral types, atmospheric parameters and chemical abundances fo...
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Observations of Reconnection Flows in a Flare on the Solar Disk: Magnetic reconnection is a well-accepted part of the theory of solar eruptive events, though the evidence is still circumstantial. Intrinsic to the reconnection picture of a solar eruptive event, particularly in the standard model for two-ribbon flares ("...
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Using the Sun to estimate Earth-like planets detection capabilities. V. Parameterizing the impact of solar activity components on radial velocities: Stellar activity induced by active structures (eg, spots, faculae) is known to strongly impact the radial velocity time series. It then limits the detection of small pla...
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A method to deconvolve stellar rotational velocities III. The probability distribution function via Maximum Likelihood utilizing Finite Distribution Mixtures: The study of accurate methods to estimate the distribution of stellar rotational velocities is important for understanding many aspects of stellar evolution....
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On the Doppler Shift and Asymmetry of Stokes Profiles of Photospheric FeI and Chromospheric MgI Lines: We analyzed the full Stokes spectra using simultaneous measurements of the photospheric (FeI 630.15 and 630.25 nm) and chromospheric (MgI b2 517.27 nm) lines. The data were obtained with the HAO/NSO Advanced Stokes ...
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The Role of Inverse Compton Scattering in Solar Coronal Hard X-ray and Gamma-ray Sources: Coronal hard X-ray (HXR) and continuum gamma-ray sources associated with the impulsive phase of solar flares have been the subject of renewed interest in recent years. They have been interpreted in terms of thin-target, nontherm...
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Planetary Nebulae in the Small Magellanic Cloud: We analyse the planetary nebulae (PNe) population of the Small Magellanic Cloud (SMC), based on evolutionary models of stars with metallicities in the range $10^{-3} \leq Z \leq 4\times 10^{-3}$ and mass $0.9 M\odot < M < 8M\odot$, evolved through the asymptotic giant br...
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The galactic unclassified B[e] star HD 50138 III. The short-term line profile variability of its photospheric lines: HD 50138 presents the B[e] phenomenon, but its nature is not clear yet. This star is known to present spectral variations, which have been associated with outbursts and shell phases. We analyze the lin...
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Verification of Asymptotic Relation for Mixed Modes in Red Giant Stars: High-precision space observations, such as made by the \kepler\ and \corot\ missions, allow us to detect mixed modes for $l = 1$ modes in their high signal-to-noise photometry data. By means of asteroseismology, the inner structure of red giant (RG...
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The Age-Rotation-Activity Relation: From Myrs to Gyrs: Over the past 40 years, observational surveys have established the existence of a tight relationship between a star's age, rotation period, and magnetic activity. This age-rotation-activity relation documents the interplay between a star's magnetic dynamo and angul...
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H-alpha as a Luminosity Class Diagnostic for K- and M-type Stars: We have identified the H-alpha absorption feature as a new spectroscopic diagnostic of luminosity class in K- and M-type stars. From high-resolution spectra of 19 stars with well-determined physical properties (including effective temperatures and stella...
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The (B0+?)+O6 system FN CMa: A case for tidal-pulsational interaction?: FN CMa is visually double with a separation of about 0.6arcsec. Sixty high-cadence VLT/UVES spectra permit the A and B components to be disentangled, as the relative contribution of each star to the total light entering the spectrograph fluctuates ...
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Atmospheric parameters of Cepheids from flux ratios with ATHOS: I. The temperature scale: Context: The effective temperature is a key parameter governing the properties of a star. For stellar chemistry, it has the strongest impact on the accuracy of the abundances derived. Since Cepheids are pulsating stars, determin...
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High-Precision Radio and Infrared Astrometry of LSPM J1314+1320AB - II: Testing Pre--Main-Sequence Models at the Lithium Depletion Boundary with Dynamical Masses: We present novel tests of pre$-$main-sequence models based on individual dynamical masses for the M7 binary LSPM J1314+1320AB. Joint analysis of our Keck...
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Kinematic evidence for feedback-driven star formation in NGC 1893: OB associations are the prevailing star forming sites in the Galaxy. Up to now, the process of how OB associations were formed remained a mystery. A possible process is self-regulating star formation driven by feedback from massive stars. However, altho...
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The Kepler and Hale observations of V523 Lyr: We present new observations of the cataclysmic variable V523 Lyr, a member of the open cluster NGC 6791. The Kepler Space telescope obtained photometric observations of this source and we examine the nearly 3 year long light curve. The observations show numerous small ampli...
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Why variable AGB stars with Long Secondary Periods aren't binaries, but are dusty: Roughly 30% of variable AGB stars show a Long Secondary Period, or LSP. These LSPs have posed something of a problem in recent years and their cause remains a mystery. By combining VLT-derived velocity curves with MACHO and OGLE light ...
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Towards understanding dynamo action in M dwarfs: Recent progress in observational studies of magnetic activity in M dwarfs urgently requires support from ideas of stellar dynamo theory. We propose a strategy to connect observational and theoretical studies. In particular, we suggest four magnetic configurations that ap...
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Detection of the Central Star of the Planetary Nebula NGC 6302: NGC 6302 is one of the highest ionization planetary nebulae known and shows emission from species with ionization potential >300eV. The temperature of the central star must be >200,000K to photoionize the nebula, and has been suggested to be up to ~ 400,00...
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Evidence of a complex structure within the 2013 August 19 coronal mass ejection. Radial and longitudinal evolution in the inner heliosphere: Context: Late on 2013 August 19, a coronal mass ejection (CME) erupted from an active region located near the far-side central meridian from Earth's perspective. The event and i...
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The Be Star HD 215227: A Candidate Gamma-ray Binary: The emission-line Be star HD 215227 lies within the positional error circle of the newly identified gamma-ray source AGL J2241+4454. We present new blue spectra of the star, and we point out the morphological and variability similarities to other Be binaries. An anal...
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Formation of the helium EUV resonance lines: Context: While classical models successfully reproduce intensities of many transition region lines, they predict helium EUV line intensities roughly an order of magnitude lower than the observed value. Aims: To determine the relevant formation mechanism(s) of the helium EU...
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The solar wind in time: a change in the behaviour of older winds?: In the present paper, we model the wind of solar analogues at different ages to investigate the evolution of the solar wind. Recently, it has been suggested that winds of solar type stars might undergo a change in properties at old ages, whereby stars o...
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Physical structure of the envelopes of intermediate-mass protostars: Context: Intermediate mass protostars provide a bridge between low- and high-mass protostars. Furthermore, they are an important component of the UV interstellar radiation field. Despite their relevance, little is known about their formation process. ...
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Activity on a Li-rich giant: DI Psc revisited: We present a new Doppler imaging study for the Li-rich single K-giant DI Psc. Surface temperature maps are reconstructed for two subsequent rotation cycles. From the time evolution of the spot distribution antisolar-type differential rotation pattern is revealed. We show m...
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Abundance ratios in GALAH DR2 and their implications for nucleosynthesis: Using a sample of 70 924 stars from the second data release of the GALAH optical spectroscopic survey, we construct median sequences of [X/Mg] vs. [Mg/H] for 21 elements, separating the high-$\alpha$/``low-Ia'' and low-$\alpha$/``high-Ia'' stella...
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Characterising the observational properties of δ Sct stars in the era of space photometry from the Kepler mission: The {\delta} Sct stars are a diverse group of intermediate-mass pulsating stars located on and near the main sequence within the classical instability strip in the Hertzsprung-Russell diagram. Many of th...
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Collisional relaxation of electrons in a warm plasma and accelerated nonthermal electron spectra in solar flares: Extending previous studies of nonthermal electron transport in solar flares which include the effects of collisional energy diffusion and thermalization of fast electrons, we present an analytic method to...
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Absolute Parameters of Young Stars: PU Pup: We present combined photometric and spectroscopic analyses of the southern binary star PU Pup. High-resolution spectra of this system were taken at the University of Canterbury Mt. John Observatory in the years 2008 and again in 2014-15. We find the light contribution of the ...
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The Automatic Identification and Tracking of Coronal Flux Ropes -- Part I: Footpoints and Fluxes: Investigating the early-stage evolution of an erupting flux rope from the Sun is important to understand the mechanisms of how it looses its stability and its space weather impacts. Our aim is to develop an efficient sch...
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Gravitational settling in pulsating subdwarf B stars and their progenitors: Diffusion of atoms can be important during quiescent phases of stellar evolution. Particularly in the very thin inert envelopes of subdwarf B stars, diffusive movements will considerably change the envelope structure and the surface abundance...
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The Ages of Stars: The age of an individual star cannot be measured, only estimated through mostly model-dependent or empirical methods, and no single method works well for a broad range of stellar types or for a full range in age. This review presents a summary of the available techniques for age-dating stars and ense...
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Magnetic Fields of New CP Stars Discovered with Kepler Mission Data: The paper presents the first results of the ongoing spectropolarimetric monitoring of magnetic fields of stars, whose chemically peculiar nature has been previously revealed with the 1-m SAO RAS telescope. We selected the sample candidates using the p...
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Response of Granulation to Small Scale Bright Features in the Quiet Sun: We detected 2.8 bright points (BPs) per Mm$^2$ in the Quiet Sun (QS) with the New Solar Telescope (NST) at Big Bear Solar Observatory; using the TiO 705.68 nm spectral line, at an angular resolution ~ 0.1'' to obtain 30 min data sequence. Some BPs...
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The Solar Neighborhood XXIV. Parallax Results from the CTIOPI 0.9-m Program: Stars with $μ$ $\ge$ 1\farcs0 yr$^{-1}$ (MOTION Sample) and Subdwarfs: We present 41 trigonometric parallaxes of 37 stellar systems, most of which have proper motions greater than 1\farcs0 yr$^{-1}$. These are the first trigonometric paral...
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Gas and dust from solar metallicity AGB stars: We study the asymptotic giant branch (AGB) evolution of stars with masses between $1~M_{\odot} - 8.5~M_{\odot}$. We focus on stars with a solar chemical composition, which allows us to interpret evolved stars in the Galaxy. We present a detailed comparison with models of t...
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Stellar granulation as seen in disk-integrated intensity. II. Theoretical scaling relations compared with observations: A large set of stars observed by CoRoT and Kepler shows clear evidence for the presence of a stellar background, which is interpreted to arise from surface convection, i.e., granulation. These obser...
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Solar LImb Prominence CAtcher and Tracker (SLIPCAT): An Automated System and Its Preliminary Statistical Results: In this paper, we present an automated system, which has the capability to catch and track solar limb prominences based on observations from EUV 304 passband. The characteristic parameters and their evolu...
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A Survey of Stellar Families: Multiplicity of Solar-Type Stars: We present the results of a comprehensive assessment of companions to solar-type stars. A sample of 454 stars, including the Sun, was selected from the Hipparcos catalog with {\pi} > 40 mas, {\sigma}_{\pi}/{\pi} < 0.05, 0.5 < B - V < 1.0 (~ F6-K3), and con...
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Sigmoid-to-Flux-Rope Transition Leading to A Loop-Like Coronal Mass Ejection: Sigmoids are one of the most important precursor structures for solar eruptions. In this Letter, we study a sigmoid eruption on 2010 August 1 with EUV data obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observ...
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Subsonic structure and optically thick winds from Wolf--Rayet stars: Wolf-Rayet star's winds can be so dense and so optically thick that the photosphere appears in the highly supersonic part of the outflow, veiling the underlying subsonic part of the star, and leaving the initial acceleration of the wind inaccessible t...
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Formation of Transient Coronal Holes during Eruption of a Quiescent Filament and its Overlying Sigmoid: By using H$\alpha$, He I 10830, EUV and soft X-ray (SXR) data, we examined a filament eruption that occurred on a quiet-sun region near the center of the solar disk on 2006 January 12, which disturbed a sigmoid ove...
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Anisotropic turbulent transport in stably stratified rotating stellar radiation zones: Rotation is one of the key physical mechanisms that deeply impact the evolution of stars. Helio- and asteroseismology reveal a strong extraction of angular momentum from stellar radiation zones over the whole Hertzsprung-Russell di...
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Nonradial Oscillations in Classical Pulsating Stars. Predictions and Discoveries: After a brief historical introduction and recalling basic concepts of stellar oscillation theory, I focus my review on interpretation of secondary periodicities found in RR Lyrae stars and Cepheids as a manifestation of nonradial mode e...
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Ejection of globular cluster interstellar media through ionization by white dwarfs: UV radiation from white dwarfs can efficiently clear Galactic globular clusters (GCs) of their intra-cluster medium (ICM). This solves the problem of the missing ICM in clusters, which is otherwise expected to build up to easily obser...
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Multiple and changing cycles of active stars II. Results: We study the time variations of the cycles of 20 active stars based on decades-long photometric or spectroscopic observations. A method of time-frequency analysis, as discussed in a companion paper, is applied to the data. Fifteen stars definitely show multiple ...
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Type II supernovae from the Carnegie Supernova Project-I. I. Bolometric light curves of 74 SNe II using uBgVriYJH photometry: The present study is the first of a series of three papers where we characterise the type II supernovae (SNe~II) from the Carnegie Supernova Project-I to understand their diversity in terms of...
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A Multiplicity Census of Intermediate-Mass Stars in Scorpius-Centaurus: Stellar multiplicity properties have been studied for much of the range from the lowest to the highest stellar masses, but intermediate-mass stars from F-type to late A-type have received relatively little attention. Here we report on a Gemini/NICI...
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Rossby Wave Instability with Self-Gravity: The Rossby wave instability (RWI) in non-self-gravitating discs can be triggered by a bump at a radius $r_0$ in the disc surface mass-density (which is proportional to the inverse potential vorticity). It gives rise to a growing non-axisymmetric perturbation [$\propto \exp(im\...
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Spectroscopic and Photometric Behaviour of LP Ori: We performed spectroscopic and photometric analyses on the early B-type LP Ori young stellar object located in the Orion Nebula. The high-resolution spectra of LP Ori was obtained at the Ankara University Kreiken Observatory in 2023, while all spectra recorded over the...
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Coronal response to magnetically-suppressed CME events in M-dwarf stars: We report the results of the first state-of-the-art numerical simulations of Coronal Mass Ejections (CMEs) taking place in realistic magnetic field configurations of moderately active M-dwarf stars. Our analysis indicates that a clear, novel, and ...
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Dynamics of the photosphere along the solar cycle from SDO/HMI: As the global magnetic field of the Sun has an activity cycle, one expects to observe some variation of the dynamical properties of the flows visible in the photosphere. We investigate the flow field during the solar cycle by analysing SDO/HMI observations...
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Evolution of the Radial Size and Expansion of Coronal Mass Ejections Investigated by Combining Remote and In-Situ Observations: A fundamental property of coronal mass ejections (CMEs) is their radial expansion, which determines the increase in the CME radial size and the decrease in the CME magnetic field strength as...
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Ionization ratios and elemental abundances in the atmosphere of 68 Tauri: We have derived the ionization ratios of twelve elements in the atmosphere of the star 68 Tauri (HD 27962) using an ATLAS9 model atmosphere with 72 layers computed for the effective temperature and surface gravity of the star. We then computed a ...
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Asteroseismology of red giants from the first four months of Kepler data: Fundamental parameters: Clear power excess in a frequency range typical for solar-type oscillations in red giants has been detected in more than 1000 stars, which have been observed during the first 138 days of the science operation of the NASA...
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Search for Alignment of Disk Orientations in Nearby Star-Forming Regions: Lupus, Taurus, Upper Scorpius, $ρ$ Ophiuchi, and Orion: Spatial correlations among proto-planetary disk orientations carry unique information on physics of multiple star formation processes. We select five nearby star-forming regions that compr...
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Spatio-kinematic models of five nova remnants: correlations between nova shell axial ratio, expansion velocity, and speed class: We present long-slit intermediate-dispersion spectroscopic observations and narrow-band direct imaging of four classical nova shells, namely TAur, HRDel, DQHer and QUVul, and the nova-like ...
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Herschel-HIFI detections of hydrides towards AFGL 2591 (Envelope emission versus tenuous cloud absorption): The Heterodyne Instrument for the Far Infrared (HIFI) onboard the Herschel Space Observatory allows the first observations of light diatomic molecules at high spectral resolution and in multiple transitions. He...
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General model of depolarization and transfer of polarization of singly ionized atoms by collisions with hydrogen atoms: Simulations of the generation of the atomic polarization is necessary for interpreting the second solar spectrum. For this purpose, it is important to rigorously determine the effects of the isotrop...
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On the Temporal Evolution of the Disc Counterpart of Type II Spicules in Quiet Sun: The type II spicule has been speculated to provide enough hot plasma to play an important role in the mass loading and heating of the corona. We analyse the disc counterpart to type II spicules, RBEs, in three high quality datasets fr...
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Korg: a modern 1D LTE spectral synthesis package: We present Korg, a new package for 1D LTE (local thermodynamic equilibrium) spectral synthesis of FGK stars, which computes theoretical spectra from the near-ultraviolet to the near-infrared, and implements both plane-parallel and spherical radiative transfer. We outlin...
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A review of the disc instability model for dwarf novae, soft X-ray transients and related objects: I review the basics of the disc instability model (DIM) for dwarf novae and soft-X-ray transients and its most recent developments, as well as the current limitations of the model, focusing on the dwarf nova case. Altho...
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Learning about AGB stars by studying the stars polluted by their outflows: A rich zoo of peculiar objects forms when Asymptotic Giant Branch (AGB) stars, undergo interactions in a binary system. For example, Barium (Ba) stars are main-sequence and red-giant stars that accreted mass from the outflows of a former AGB c...
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The variable 6307A emission line in the spectrum of Eta Carinae: blueshifted [S III] 6313A from the interacting winds: The 6307A emission line in the spectrum of Eta Car (Martin et al. 2006) is blue-shifted [S III] 6313A emission originating from the outer wind structures of the massive binary system. We realized the...
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Time-resolved optical observations of five cataclysmic variables detected by INTEGRAL: The ESA gamma-ray telescope, INTEGRAL, is detecting relatively more intrinsically rare cataclysmic variables (CVs) than were found by surveys at lower energies. Specifically, a large fraction of the CVs that are INTEGRAL sources co...
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NOEMA maps the CO $J = 2-1$ environment of the red supergiant $μ$ Cep: Red supergiant stars are surrounded by a gaseous and dusty circumstellar environment created by their mass loss which spreads heavy elements into the interstellar medium. The structure and the dynamics of this envelope are crucial to understand the ...
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A kinematic study of the disc-outflow system around a high-mass protostar G59.783+0.065 probed by methanol and water masers: Class II CH3OH masers are used as a convenient tracer of disc-like structures in high-mass star formation. However, more than half of them show a complex distribution in Very Long Baseline Inte...
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Extreme Ultraviolet Late-Phase Flares: Before and During the Solar Dynamics Observatory Mission: The SDO EUV observations have revealed interesting characteristics of warm coronal emissions, which peak soon after the hot coronal X-ray emissions peak during a flare and then sometimes peak for a second time hours after...
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Stellar magnetism: empirical trends with age and rotation: We investigate how the observed large-scale surface magnetic fields of low-mass stars (~0.1 -- 2 Msun), reconstructed through Zeeman-Doppler imaging (ZDI), vary with age t, rotation and X-ray emission. Our sample consists of 104 magnetic maps of 73 stars, from ...
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Constraints on the distance moduli, helium and metal abundances, and ages of globular clusters from their RR Lyrae and non-variable horizontal-branch stars. II. Multiple stellar populations in 47Tuc, M3, and M13: We present a new set of horizontal-branch (HB) models computed with the MESA stellar evolution code. ...
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Multi-epoch high-resolution spectroscopy of SN2011fe - Linking the progenitor to its environment: This study attempts to establish a link between the reasonably well known nature of the progenitor of SN2011fe and its surrounding environment. This is done with the aim of enabling the identification of similar systems ...
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The two-dimensional internal rotation of KIC11145123: The two-dimensional internal rotation of KIC11145123 has been inferred via asteroseismology. Based on the Optimally Localized Averaging method and a simple three-zone modeling of the internal rotation, we have found evidence for a contrast between the internal rotat...
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Multicolor Photoelectric WBVR-Observations of the CBS HZ~Her=Her~X-1 in 1986--1988: We present results of four-color WBVR- photoelectric observations of the close binary HZ~Her=HER~X-1 in 1986--1988. As a rule, the duration of the observations exceeded two 35-day X-ray orbital periods in the 1986--1988 observing seas...
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Comparison of solar wind speed estimates from nearly simultaneous IPS observations at 327 and 111 MHz: Results are presented of a comparison between solar wind speed estimates made using the time delays between 3 pairs of 327 MHz antennas at ISEE and estimates made by modeling the temporal power spectra observed with...
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Post-flare UV light curves explained with thermal instability of loop plasma: In the present work we study the C8 flare occurred on September 26, 2000 at 19:49 UT and observed by the SOHO/SUMER spectrometer from the beginning of the impulsive phase to well beyond the disappearance in the X-rays. The emission first de...
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The Evolution of Protoplanetary Disks: Probing the Inner Disk of Very Low Accretors: We report FUV, optical, and NIR observations of three T Tauri stars in the Orion OB1b subassociation with H$\alpha$ equivalent widths consistent with low or absent accretion and various degrees of excess flux in the mid-infrared. We ...
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