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Abundances in the Herbig Ae star HD 101412: Abundance anomalies; Lambda
Boo-Vega characteristics?: Context: Recent attention has been directed to abundance variations among
very young stars.
Aims: To perform a detailed abundance study of the Herbig Ae star HD 101412,
taking advantage of its unusually sharp spectral... | astro-ph_SR |
Six New Recycled Globular Cluster Pulsars Discovered with the Green Bank
Telescope: We have completed sensitive searches for new pulsars in seven globular
clusters using the Robert C. Byrd Green Bank Telescope, and have discovered six
new recycled pulsars (four in NGC 6517 and two in M22), five of which are fully
rec... | astro-ph_SR |
Partially-erupting prominences: a comparison between observations and
model-predicted observables: AIM: To investigate several partially-erupting prominences to study their
relationship with other CME-associated phenomena and to compare these
observations with observables predicted by a model of partially-expelled fl... | astro-ph_SR |
The Surface Magnetic Activity of the Weak-Line T Tauri Stars TWA 7 and
TWA 25: We present an analysis of spectropolarimetric observations of the low-mass
weak-line T Tauri stars TWA 25 and TWA 7. The large-scale surface magnetic
fields have been reconstructed for both stars using the technique of Zeeman
Doppler imagi... | astro-ph_SR |
Hydrodynamical instabilities induced by atomic diffusion in A stars and
their consequences: Aims. Atomic diffusion, including the effect of radiative accelerations on
individual elements, leads to important variations of the chemical composition
inside the stars. The accumulation in specific layers of the elements, w... | astro-ph_SR |
The Closest View of a Fast Coronal Mass Ejection: How Faulty Assumptions
near Perihelion Lead to Unrealistic Interpretations of PSP/WISPR Observations: We report on the closest view of a coronal mass ejection observed by the
Parker Solar Probe (PSP)/Wide-field Imager for {Parker} Solar PRobe (WISPR)
instrument on Sep... | astro-ph_SR |
Modeling Magnetically Channeled Winds in 3D: I. Isothermal Simulations
of a Magnetic O Supergiant: In this paper we present the first set of 3D magnetohydrodynamic (MHD)
simulations performed with the riemann geomesh code. We study the dynamics of
the magnetically channeled winds of magnetic massive stars in full thr... | astro-ph_SR |
Continuum and line emission of flares on red dwarf stars: The emission spectrum has been calculated of a homogeneous pure hydrogen
layer, which parameters are typical for a flare on a red dwarf. The ionization
and excitation states were determined by the solution of steady-state equations
taking into account the contin... | astro-ph_SR |
Arrival time calculation for interplanetary coronal mass ejections with
circular fronts and application to STEREO observations of the 2009 February
13 eruption: A goal of the NASA STEREO mission is to study the feasibility of forecasting
the direction, arrival time and internal structure of solar coronal mass
eject... | astro-ph_SR |
Extended radio emission associated with a breakout eruption from the
back side of the Sun: Context. Coronal mass ejections (CMEs) on the Sun are the largest explosions
in the Solar System that can drive powerful plasma shocks. The eruptions,
shocks, and other processes associated to CMEs are efficient particle
accele... | astro-ph_SR |
Uncovering new white dwarf - open cluster associations using Gaia DR3: Context: Open clusters (OCs) provide homogeneous samples of white dwarfs
(WDs) with known distances, extinctions, and total ages. The unprecedented
astrometric precision of \textit{\textit{Gaia}} allows us to identify many
novel OC--WD pairs. Studyi... | astro-ph_SR |
Very fast variations of SiO maser emission in evolved stars: Context. Stars on the asymptotic giant branch (AGB) are long-period variables
that present strong flux variations at almost all wavelengths, including the
SiO maser lines. The periods of these variations are of 300-500 days in
Mira-type stars and somewhat sho... | astro-ph_SR |
Peeking Between the Pulses: The Far-UV Spectrum of the Previously Unseen
White Dwarf in AR Scorpii: The compact object in the interacting binary AR Sco has widely been presumed
to be a rapidly rotating, magnetized white dwarf (WD), but it has never been
detected directly. Isolating its spectrum has proven difficult b... | astro-ph_SR |
WISE Y Dwarfs As Probes of the Brown Dwarf-Exoplanet Connection: We have determined astrometric positions for 15 WISE-discovered late-type
brown dwarfs (6 T8-9 and 9 Y dwarfs) using the Keck II telescope, the Spitzer
Space Telescope, and the Hubble Space Telescope. Combining data from 8 to 20
epochs we derive parallact... | astro-ph_SR |
Close Binary Companions to APOGEE DR16 Stars: 20,000 Binary-star Systems
Across the Color-Magnitude Diagram: Many problems in contemporary astrophysics---from understanding the formation
of black holes to untangling the chemical evolution of galaxies---rely on
knowledge about binary stars. This, in turn, depends on d... | astro-ph_SR |
The timescale of low-mass proto-helium white dwarf evolution: A large number of low-mass (< 0.20 M_sun) helium white dwarfs (He WDs) have
recently been discovered. The majority of these are orbiting another WD or a
millisecond pulsar (MSP) in a close binary system; a few examples are found to
show pulsations or to have... | astro-ph_SR |
Revealing the Two `Horns' of Taurus with GAIA DR2: We investigate the spatial properties of sources from the GAIA catalogue
previously identified as being members of the Taurus star forming region and
which appear in the Spitzer catalogue. We study an area of sky of 10x15 deg,
centred on Right Ascension (2000.0) = 68.5... | astro-ph_SR |
A cavity and further radial substructures in the disk around HD~97048: Context: Gaps, cavities and rings in circumstellar disks are signposts of
disk evolution and planet-disk interactions. We follow the recent suggestion
that Herbig Ae/Be disks with a flared disk harbour a cavity, and investigate
the disk around HD~97... | astro-ph_SR |
Seismological determination of the Alfvén speed and plasma-beta in
solar photospheric bright points: The Alfv\'{e}n speed and plasma beta in photospheric bright points observed
by the Broadband Filter Imager (BFI) of the Solar Optical Telescope (SOT) on
board the \textit{Hinode} satellite, are estimated seismological... | astro-ph_SR |
The L dwarf/T dwarf transition: multiplicity, magnetic activity and
mineral meteorology across the hydrogen burning limit: The transition between the L dwarf and T dwarf spectral classes is one of the
most remarkable along the stellar/brown dwarf Main Sequence, separating sources
with photospheres containing mineral ... | astro-ph_SR |
Spectral analysis of 3D MHD models of coronal structures: We study extreme-ultraviolet emission line spectra derived from
three-dimensional magnetohydrodynamic models of structures in the corona. In
order to investigate the effects of increased magnetic activity at photospheric
levels in a numerical experiment, a much ... | astro-ph_SR |
The Cepheid Impostor HD 18391 and its Anonymous Parent Cluster: New and existing photometry for the G0 Ia supergiant HD 18391 is analyzed in
order to confirm the nature of the variablity previously detected in the star,
which lies off the hot edge of the Cepheid instability strip. Small-amplitude
variability at a level... | astro-ph_SR |
The EBLM project -- IX. Five fully convective M-dwarfs, precisely
measured with CHEOPS and TESS light curves: Eclipsing binaries are important benchmark objects to test and calibrate
stellar structure and evolution models. This is especially true for binaries
with a fully convective M-dwarf component for which direct... | astro-ph_SR |
High Level Magnetic Activity Nature of an Eclipsing Binary KIC 12418816: We present comprehensive spectroscopic and photometric analysis of the
detached eclipsing binary KIC 12418816, which is composed of two very similar
and young main sequence stars of spectral type K0 on a circular orbit.
Combining spectroscopic and... | astro-ph_SR |
The Initial Magnetic Field Distribution in AB Stars: Stars are born with magnetic fields, but the distribution of their initial
field strengths remains uncertain. We combine observations with theoretical
models of magnetic field evolution to infer the initial distribution of
magnetic fields for AB stars in the mass ran... | astro-ph_SR |
Updated High-Temperature Opacities for the Dartmouth Stellar Evolution
Program and their Effect on the Jao Gap Location: The Jao Gap, a 17 percent decrease in stellar density at $M_G \sim10$
identified in both Gaia DR2 and EDR3 data, presents a new method to probe the
interior structure of stars near the fully convec... | astro-ph_SR |
On the circumstellar envelopes of semi-regular long-period variables: The mass loss process along the AGB phase is crucial for the formation of
circumstellar envelopes (CSEs), which in the post-AGB phase will evolve into
planetary nebulae (PNe). There are still important issues that need to be
further explored in this ... | astro-ph_SR |
Energetic consequences of flux emergence: When magnetic field in the solar convection zone buoyantly rises to pierce
the visible solar surface (photosphere), the atmosphere (corona) above this
surface must respond in some way. One response of the coronal field to
photospheric forcing is the creation of stress in the ma... | astro-ph_SR |
The CIDA Variability Survey of Orion OB1 II: demographics of the young,
low-mass stellar populations: We present results of our large scale, optical, multi-epoch photometric
survey of ~180 square degrees across the Orion OB1 association, complemented
with extensive follow up spectroscopy. We map and characterize in a... | astro-ph_SR |
Abundances of Suprathermal Heavy Ions in CIRs on STEREO during the
Minimum of Solar Cycle 23: We examine the composition of the 0.1 - 1 MeV/n interplanetary heavy ions
from H to Fe in corotating interaction regions (CIRs) measured by the SIT
(Suprathermal Ion Telescope) instrument. We use observations taken on board ... | astro-ph_SR |
Coronal radiation belts: The magnetic field of the solar corona has a large-scale dipole character,
which maps into the bipolar field in the solar wind. Using standard
representations of the coronal field, we show that high-energy ions can be
trapped stably in these large-scale closed fields. The drift shells that
desc... | astro-ph_SR |
Hydrodynamic models of pulsation period evolution in R Hydrae: Pulsation period evolution during the helium-shell flash in the Mira variable
R Hya is investigated using consistent stellar evolution and non-linear stellar
pulsation computations. The initial and time-dependent inner boundary
conditions for the equations ... | astro-ph_SR |
Parameters of rotating neutron stars with and without hyperons: The discovery of a 2 Msun neutron star provided a robust constraint for the
theory of exotic dense matter, bringing into question the existence of strange
baryons in the interiors of neutron stars. Although many theories fail to
reproduce this observationa... | astro-ph_SR |
Observations and numerical models of solar coronal heating associated
with spicules: Spicules have been proposed as significant contributors to the mass and
energy balance of the corona. While previous observations have provided a
glimpse of short-lived transient brightenings in the corona that are associated
with sp... | astro-ph_SR |
The intermediate neutron-capture process and carbon-enhanced metal-poor
stars: Carbon-enhanced metal-poor (CEMP) stars in the Galactic Halo display
enrichments in heavy elements associated with either the s (slow) or the r
(rapid) neutron-capture process (e.g., barium and europium respectively), and
in some cases the... | astro-ph_SR |
Episodic modulations in supernova radio light curves from luminous blue
variable supernova progenitor models: <Context> Ideally, one would like to know which type of core-collapse SNe is
produced by different progenitors and the channels of stellar evolution leading
to these progenitors. These links have to be very w... | astro-ph_SR |
Determination of stellar atmospheric parameters for a sample of the
post-AGB stars: We report for the first time the stellar atmospheric parameters for a a set
of post-AGB stars classified by Suarez et al. (2006). The stellar spectra were
taken from optical region, with low-resolution and have different spectral
rang... | astro-ph_SR |
Preliminary results of giant pulse investigations from Crab pulsar with
Radioastron: Giant pulses from Crab pulsar were observed together with Radioastron space
radiotelescope, Global EVN radio telescopes and Kvazar-KVO VLBI stations to
study the scattering effects in the ISM. Five observing sessions were conducted
a... | astro-ph_SR |
Oscillator Strength Measurements of Atomic Absorption Lines from Stellar
Spectra: We develop a new method to determine oscillator strength values of atomic
absorption lines with state-of-the-art detailed spectral synthesis calculations
of the optical spectrum of the Sun and of standard spectral reference stars. We
up... | astro-ph_SR |
Search for aluminium monoxide in the winds of oxygen-rich AGB stars: Aluminium monoxide, AlO, is likely efficiently depleted from the gas around
oxygen-rich evolved stars to form alumina clusters and dust seeds. Its presence
in the extended atmospheres of evolved stars has been derived from optical
spectroscopy. More r... | astro-ph_SR |
Chemical Abundance Signature of J0023+0307 -- A Second-Generation
Main-Sequence Star with [Fe/H]<-6: We present a chemical abundance analysis of the faint halo metal-poor
main-sequence star J0023+0307, with [Fe/H]<-6.3, based on a high-resolution
(R~35,000) Magellan/MIKE spectrum. The star was originally found to hav... | astro-ph_SR |
Protostellar Evolution in Serpens Main: Possible Origin of Disk-Size
Diversity: We have observed the submillimeter continuum condensations SMM2, SMM4, SMM9,
and SMM11 in the star forming cluster Serpens Main using the Atacama Large
Millimeter/submillimeter Array during Cycle 3 in the 1.3 mm continuum, 12CO
J=2-1, SO ... | astro-ph_SR |
3-D Kinematics of the near-IR HH 223 outflow in L723: In this work we derive the full 3-D kinematics of the near-infrared outflow
HH 223, located in the dark cloud Lynds 723 (L723), where a well-defined
quadrupolar CO outflow is found. HH 223 appears projected onto the two lobes of
the east-west CO outflow. The radio c... | astro-ph_SR |
Mind the Gap I: H$α$ Activity of M Dwarfs Near the Partially/Fully
Convective Boundary and a New H$α$ Emission Deficiency Zone on the Main
Sequence: Since identifying the gap in the H-R Diagram (HRD) marking the transition
between partially and fully convective interiors, a unique type of slowly
pulsating M dwarf h... | astro-ph_SR |
Non-Ideal Magnetohydrodynamic Simulations of the Two-Stage Fragmentation
Model for Cluster Formation: We model molecular cloud fragmentation with thin disk non-ideal
magnetohydrodynamic simulations that include ambipolar diffusion and partial
ionization that transitions from primarily ultraviolet dominated to cosmic ... | astro-ph_SR |
Correlated Strontium and Barium Isotopic Compositions of Acid-Cleaned
Single Silicon Carbides from Murchison: We present strontium, barium, carbon, and silicon isotopic compositions of 61
acid-cleaned presolar SiC grains from Murchison. Comparison with previous data
shows that acid washing is highly effective in remo... | astro-ph_SR |
Gravitational waves from pulsars in the context of magnetic ellipticity: In one of our previous articles we have considered the role of a time
dependent magnetic ellipticity on pulsars' braking indices and on the putative
gravitational waves these objects can emit. Since only nine of more than 2000
known pulsars have a... | astro-ph_SR |
HST Low Resolution Stellar Library: Hubble Space Telescope's (HST) Space Telescope Imaging Spectrograph (STIS)
targeted 556 stars in a long-running program called Next Generation Spectral
Library (NGSL) via proposals GO9088, GO9786, GO10222, and GO13776. Exposures
through three low resolution gratings provide wavelengt... | astro-ph_SR |
HAZMAT VI: The Evolution of Extreme Ultraviolet Radiation Emitted from
Early M Star: Quantifying the evolution of stellar extreme ultraviolet (EUV, 100 -- 1000
$\overset{\circ}{A}$) emission is critical for assessing the evolution of
planetary atmospheres and the habitability of M dwarf systems. Previous studies
from... | astro-ph_SR |
The (non-)variability of magnetic chemically peculiar candidates in the
Large Magellanic Cloud: The galactic magnetic chemically peculiar (mCP) stars of the upper main
sequence are well known as periodic spectral and light variables. The observed
variability is obviously caused by the uneven distribution of overabund... | astro-ph_SR |
Gaia18aen: First symbiotic star discovered by Gaia: Besides the astrometric mission of the Gaia satellite, its repeated and
high-precision measurements serve also as an all-sky photometric transient
survey. The sudden brightenings of the sources are published as Gaia
Photometric Science Alerts and are made publicly ava... | astro-ph_SR |
Transit Timing Observations of the Extrasolar Hot-Neptune Planet GL 436b: Gliese 436 is an M dwarf with a mass of 0.45 Msun and hosts the extrasolar
planet GL 436b [3, 6, 7, 2], which is currently the least massive transiting
planet with a mass of ~23.17 Mearth [10], and the only planet known to transit
an M dwarf. GL ... | astro-ph_SR |
Young Stars near Cometary Globule CG 30 in the Tumultuous Gum Nebula: We have conducted a high-dispersion ($R \sim$ 34,000) optical spectroscopic
study of 10 young stars near the cometary gloule CG 30 in the Gum Nebula, a
diffuse H \textsc{ii} region home to at least 32 cometary globules. All 10
spectroscopically obser... | astro-ph_SR |
RR Lyrae stars in the globular cluster Palomar 2: A CCD VI imaging time-series over 11-year is employed to explore the light
curves of stars in the field of Palomar 2. We discovered 20 RRab and 1 RRc
variables. A revision of Gaia-DR3 data enabled us to identify 10 more variables
and confirm the RRab nature of 6 of them... | astro-ph_SR |
Observed luminosity spread in young clusters and Fu Ori stars: a unified
picture: The idea that non steady accretion during the embedded phase of protostar
evolution can produce the observed luminosity spread in the Herzsprung-Russell
diagram (HRD) of young clusters has recently been called into question.
Observation... | astro-ph_SR |
Large-amplitude longitudinal oscillations in solar prominences simulated
with different resolutions: Large-amplitude longitudinal oscillations (LALOs) in solar prominences have
been widely studied in the last decades. However, their damping and
amplification mechanisms are not well understood. In this study, we inves... | astro-ph_SR |
Optical and X-ray studies of three polars: RX J0859.1+0537, RX
J0749.1-0549, and RX J0649.8-0737: We present optical photometric and spectroscopic observations, and an
analysis of archival X-ray data of three polars: RX J0859.1+0537, RX
J0749.1-0549, and RX J0649.8-0737. Optical light curves of these three polars
rev... | astro-ph_SR |
On the Performance of Multi-Instrument Solar Flare Observations During
Solar Cycle 24: The current fleet of space-based solar observatories offers us a wealth of
opportunities to study solar flares over a range of wavelengths. Significant
advances in our understanding of flare physics often come from coordinated
obse... | astro-ph_SR |
Polarization due to rotational distortion in the bright star Regulus: Polarization in stars was first predicted by Chandrasekhar [1] who calculated
a substantial linear polarization at the stellar limb for a pure
electron-scattering atmosphere. This polarization will average to zero when
integrated over a spherical sta... | astro-ph_SR |
Sunspot Rotation as a Driver of Major Solar Eruptions in NOAA Active
Region 12158: We studied the developing conditions of sigmoid structure under the influence
of magnetic non-potential characteristics of a rotating sunspot in the active
region (AR) 12158. Vector magnetic field measurements from Helioseismic
Magneti... | astro-ph_SR |
Formation and Eruption of Hot Channels during an M6.5 Class Solar Flare: We investigate the formation and eruption of hot channels associated with the
M6.5 class flare (SOL2015-06-22T18:23) occurring in NOAA AR 12371 on 2015 June
22. Two flare precursors are observed before the flare main phase. Observations
in 94 {\AA... | astro-ph_SR |
MIDI interferometry of massive YSOs: Updates on the MPIA programme: Information about the inner structure of young stellar objects is crucial for
understanding how the central forming stars gain their mass. However,
especially for observations of (usually further away) high-mass young stellar
objects, conventional imag... | astro-ph_SR |
Evolutionary tracks of massive stars with different rotation and
metallicity in neutrino H-R diagram: Neutrino losses play a crucial role in the evolution of massive stars. We
study the neutrino luminosity of stars ranging from 20 to 90 M_{\odot} from
Zero Age Main Sequence (ZAMS) to Fe Core Collapse (FeCC) with diff... | astro-ph_SR |
A New Multi-wavelength Solar Telescope: Optical and Near-infrared Solar
Eruption Tracer (ONSET): A new multi-wavelength solar telescope, Optical and Near-infrared Solar
Eruption Tracer (ONSET) of Nanjing University, was constructed, being
fabricated by Nanjing Institute of Astronomical Optics & Technology and run in
... | astro-ph_SR |
PEPSI deep spectra. III. A chemical analysis of the ancient planet-host
star Kepler-444: We obtained an LBT/PEPSI spectrum with very high resolution and high
signal-to-noise ratio (S/N) of the K0V host Kepler-444, which is known to host
5 sub-Earth size rocky planets. The spectrum has a resolution of R=250,000, a
con... | astro-ph_SR |
New outburst of the symbiotic nova AG Peg after 165 years: AG Peg is known as the slowest symbiotic nova, which experienced its
nova-like outburst around 1850. After 165 years, during June of 2015, it
erupted again showing characteristics of the Z And-type outburst. The primary
objective is to determine basic character... | astro-ph_SR |
Extraordinary Solar Modulation Effects On Galactic Cosmic Rays Observed
By V1 Near The Heliopause: We discuss two extraordinary increases of cosmic ray intensity observed by
Voyager 1 in the last 1.1 AU before heliopause crossing, Aug 2012 at 121.7 AU.
The two increases are roughly similar in amplitude and result in ... | astro-ph_SR |
SN 2017ens: The Metamorphosis of a Luminous Broad-lined Type Ic
Supernova into an SN IIn: We present observations of supernova (SN) 2017ens, discovered by the ATLAS
survey and identified as a hot blue object through the GREAT program. The
redshift z=0.1086 implies a peak brightness of M_g=-21.1 mag, placing the
objec... | astro-ph_SR |
Rotating massive O stars with non-spherical 2D winds: We present solutions for the velocity field and mass-loss rates for 2D
axisymmetric outflows, as well as for the case of mass accretion through the
use of the Lambert W-function. For the case of a rotating radiation-driven wind
the velocity field is obtained analyti... | astro-ph_SR |
Influence of magnetic activity on the determination of stellar
parameters through asteroseismology: Magnetic activity changes the gravito-acoustic modes of solar-like stars and
in particular their frequencies. There is an angular-degree dependence that is
believed to be caused by the non-spherical nature of the magne... | astro-ph_SR |
Testing Disk-Locking in NGC 2264: We test analytic predictions from different models of magnetospheric
accretion, which invoke disk-locking, using stellar and accretion parameters
derived from models of low resolution optical spectra of 36 T Tauri stars
(TTSs) in NGC 2264 (age~3 Myrs). Little evidence is found for mode... | astro-ph_SR |
Oscillations above sunspots from the temperature minimum to the corona: Context. An analysis of the oscillations above sunspots was carried out using
simultaneous ground-based and Solar Dynamics Observatory (SDO) observations
(SiI 10827A, HeI 10830A, FeI 6173A, 1700A, HeII 304A, FeIX 171A).
Aims. Investigation of the... | astro-ph_SR |
Calibrating the surface brightness - color relation for late-type red
giants stars in the visible domain using VEGA/CHARA interferometric
observations: The surface brightness - color relationship (SBCR) is a poweful tool for
determining the angular diameter of stars from photometry. It was for instance
used to deri... | astro-ph_SR |
Wind mass-loss rates of stripped stars inferred from Cygnus X-1: Recent observations of the high-mass X-ray binary Cygnus X-1 have shown that
both the companion star (41 solar masses) and the black hole (21 solar masses)
are more massive than previously estimated. Furthermore, the black hole appears
to be nearly maxima... | astro-ph_SR |
Three-dimensional delayed-detonation models with nucleosynthesis for
Type Ia supernovae: We present results for a suite of fourteen three-dimensional, high resolution
hydrodynamical simulations of delayed-detonation modelsof Type Ia supernova (SN
Ia) explosions. This model suite comprises the first set of three-dimen... | astro-ph_SR |
The (non-)variability of magnetic chemically peculiar candidates in the
Large Magellanic Cloud: The galactic magnetic chemically peculiar (mCP) stars of the upper main
sequence are well known as periodic spectral and light variables. The observed
variability is obviously caused by the uneven distribution of overabund... | astro-ph_SR |
Imaging sub-milliarcsecond stellar features with intensity
interferometry using air Cherenkov telescope arrays: Recent proposals have been advanced to apply imaging air Cherenkov telescope
arrays to stellar intensity interferometry (SII). Of particular interest is the
possibility of model-independent image recovery a... | astro-ph_SR |
Beryllium detection in the very fast nova ASASSN-16kt (V407 Lupi): We present high-resolution spectroscopic observations of the fast nova
ASASSN-16kt (V407 Lup). A close inspection of spectra obtained at early stages
has revealed the presence of low-ionization lines, and among the others we have
identified the presence... | astro-ph_SR |
Direct Imaging Explorations for Companions around Mid-Late M Stars from
the Subaru/IRD Strategic Program: The Subaru telescope is currently performing a strategic program (SSP) using
the high-precision near-infrared (NIR) spectrometer IRD to search for
exoplanets around nearby mid/late-M~dwarfs via radial velocity (R... | astro-ph_SR |
Asteroseismology of the $δ$ Scuti star HD 50844: Aims. We aim to probe the internal structure and investigate more detailed
information of the $\delta$ Scuti star HD 50844 with asteroseismology. Methods.
We analyse the observed frequencies of the $\delta$ Scuti star HD 50844
obtained by Balona (2014), and search for po... | astro-ph_SR |
Simulations of Protoplanetary Disk Dispersal: Stellar Mass Dependence of
the Disk Lifetime: Recent infrared and submillimeter observations suggest that the
protoplanetary disk lifetime depends on the central stellar mass. The disk
dispersal is thought to be driven by viscous accretion, magneto-hydrodynamics
(MHD) win... | astro-ph_SR |
From the atmosphere to the circumstellar environment in cool evolved
stars: We discuss and illustrate contributions that optical interferometry has made
on our current understanding of cool evolved stars. We include red giant branch
(RGB) stars, asymptotic giant branch (AGB) stars, and red supergiants (RSGs).
Studies... | astro-ph_SR |
ALMA Imaging of Millimeter/Submillimeter Continuum Emission in Orion KL: We have carried out high resolution observations with Atacama Large
Millimeter/Submillimeter Array (ALMA) of continuum emission from Orion KL
region. We identify 11 compact sources at ALMA band 6 (245 GHz) and band 7 (339
GHz), including Hot Core,... | astro-ph_SR |
Magnetic activities on two single-lined RS Canum Venaticorum binaries IM
Pegasi and $σ$ Geminorum: We present the study on continuous high-resolution spectroscopic observations
of two long-period single-lined RS Canum Venaticorum (RS CVn) binary stars IM
Pegasi (IM Peg) and $\sigma$ Geminorum ($\sigma$ Gem), obtained... | astro-ph_SR |
A very young, compact bipolar H$_2$O maser outflow in the
intermediate-mass star-forming LkH$α$ 234 region: We report multi-epoch VLBI H$_2$O maser observations towards the compact
cluster of YSOs close to the Herbig Be star LkH$\alpha$ 234. This cluster
includes LkH$\alpha$ 234 and at least nine more YSOs that are f... | astro-ph_SR |
Emergence of magnetic flux generated in a solar convective dynamo. I:
Formation of Sunspots and Active regions, and Origin of Their Asymmetries: We present a realistic numerical model of sunspot and active region formation
based on the emergence of flux bundles generated in a solar convective dynamo.
To this end we u... | astro-ph_SR |
Solid-state production of complex organic molecules: H-atom addition
versus UV irradiation: Complex organic molecules (COMs) have been observed in comets, hot cores and
cold dense regions of the interstellar medium. It is generally accepted that
these COMs form on icy dust grain through the recombination reaction of
... | astro-ph_SR |
Envelope Convection, Surface Magnetism and Spots in A- and late B-type
Stars: Weak magnetic fields have recently been detected in a number of A-type stars,
including Vega and Sirius. At the same time, space photometry observations of
A- and late B-type stars from Kepler and TESS have highlighted the existence of
rota... | astro-ph_SR |
The Cluster AgeS Experiment (CASE). Variable stars in the field of the
globular cluster M10: The field of the globular cluster M10 (NGC 6254) was monitored between 1998
and 2015 in a search for variable stars. V -light curves were derived for 40
variables or likely variables, most of which are new detections. Proper ... | astro-ph_SR |
Off-disk straylight measurements for the Swedish 1-meter Solar Telescope: Context. Accurate photometry with ground based solar telescopes requires
characterization of straylight. Scattering in Earth's atmosphere and in the
telescope optics are potentially significant sources of straylight, for which
the point spread fu... | astro-ph_SR |
Measuring the Magnetic Field Strength of the Quiet Solar Corona Using
"EIT Waves": Variations in the propagation of globally-propagating disturbances (commonly
called "EIT waves") through the low solar corona offer a unique opportunity to
probe the plasma parameters of the solar atmosphere. Here, high-cadence
observa... | astro-ph_SR |
A Statistical Survey of Hard X-ray Spectral Characteristics of Solar
Flares with Two Footpoints: Using RHESSI data, we have analyzed some 172 hard X-ray peaks during 53 solar
flares which exhibited a double-footpoint structure. Fitting both footpoints
with power-laws, we find that spectral index differences range mos... | astro-ph_SR |
Exploring the Nature of EUV Waves in a Radiative Magnetohydrodynamic
Simulation: Coronal extreme-ultraviolet (EUV) waves are large-scale disturbances
propagating in the corona, whose physical nature and origin have been discussed
for decades. We report the first three dimensional (3D) radiative
magneto-hydrodynamic (... | astro-ph_SR |
Interpretation of CEMP(s) and CEMP(s + r) Stars with AGB Models: Asymptotic Giant Branch (AGB) stars play a fundamental role in the s-process
nucleosynthesis during their thermal pulsing phase. The theoretical predictions
obtained by AGB models at different masses, s-process efficiencies, dilution
factors and initial r... | astro-ph_SR |
Stellar Yields of Rotating First Stars. II. Pair Instability Supernovae
and Comparison with Observations: Recent theory predicts that a first star is born with a massive initial mass
of $\gtrsim$ 100 $M_\odot$. Pair instability supernova (PISN) is a common fate
for such a massive star. Our final goal is to prove the ... | astro-ph_SR |
A New Look at the YY CrB Binary System: This study presented a new analysis for the TESS-observed W Ursae Majoris (W
UMa) binary star YY Coronea Borealis (YY CrB). The light curve was analyzed by
the PHysics Of Eclipsing BinariEs (PHOEBE) Python version together with the
Markov chain Monte Carlo (MCMC) method. The ligh... | astro-ph_SR |
Searching For Wide Binary Stars with Non-coeval Components in the
Southern Sky: We have completed our observational program to search for wide binary systems
with non-coeval components in the southern sky and report our results here. The
final set of four systems was spectroscopically investigated in this paper. No
b... | astro-ph_SR |
BD +44 493: A Ninth Magnitude Messenger from the Early Universe; Carbon
Enhanced and Beryllium Poor: We present a 1D LTE chemical abundance analysis of the very bright (V=9.1)
Carbon-Enhanced Metal-Poor (CEMP) star BD +44 493, based on high-resolution,
high signal-to-noise spectra obtained with Subaru/HDS. The star i... | astro-ph_SR |
The 12C + 12C reaction and the impact on nucleosynthesis in massive
stars: Despite much effort in the past decades, the C-burning reaction rate is
uncertain by several orders of magnitude, and the relative strength between the
different channels 12C(12C,alpha)20Ne, 12C(12C,p)23Na and 12C(12C,n)23Mg is
poorly determin... | astro-ph_SR |
The VLT-FLAMES Tarantula Survey XXV. Surface nitrogen abundances of
O-type giants and supergiants: Theoretically, rotation-induced chemical mixing in massive stars has far
reaching evolutionary consequences, affecting the sequence of morphological
phases, lifetimes, nucleosynthesis, and supernova characteristics. Usi... | astro-ph_SR |
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