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The Celestial Sign in the Anglo-Saxon Chronicle in the 770s: Insights on
Contemporary Solar Activity: The anomalous concentration of radiocarbon in 774/775 attracted intense
discussion on its origin, including the possible extreme solar event(s)
exceeding any events in observational history. Anticipating such extreme... | astro-ph_SR |
Stellar mid-life crisis: subcritical magnetic dynamos of solar-like
stars and the breakdown of gyrochronology: Recent observations reveal the surprising breakdown of stellar gyrochronology
relations at about the Sun's age hinting that middle-aged, solar-like stars
transition to a magnetically inactive future. We prov... | astro-ph_SR |
On the energy dissipation rate at the inner edge of circumbinary discs: We study, by means of numerical simulations and analysis, the details of the
accretion process from a disc onto a binary system. We show that energy is
dissipated at the edge of a circumbinary disc and this is associated with the
tidal torque that ... | astro-ph_SR |
The First Extensive Exploration of UV-bright Stars in the Globular
Cluster NGC 2808: In this study, we identified and characterized the hot and luminous UV-bright
stars in the globular cluster NGC 2808. We combined data from the Ultra Violet
Imaging Telescope (UVIT) on-board the Indian space satellite, AstroSat, with... | astro-ph_SR |
Testing Angular Momentum Transport and Wind Loss in Intermediate Mass
Core Helium Burning Stars: Stars between two and three solar masses rotate rapidly on the main sequence,
and their rotation rates in the core helium burning (secondary clump) phase can
therefore be used to test models of angular momentum loss used ... | astro-ph_SR |
Binary stars as the key to understanding planetary nebulae: Planetary nebulae are traditionally considered to represent the final
evolutionary stage of all intermediate-mass stars ($\sim$0.7-8Msol). Recent
evidence seems to contradict this picture. In particular, since the launch of
the Hubble Space Telescope it has be... | astro-ph_SR |
A detailed study of the barium central star of the planetary nebula
Abell 70: We present a detailed study of the barium star at the heart of the planetary
nebula Abell 70. Time-series photometry obtained over a period of more than ten
years demonstrates that the barium-contaminated companion is a rapid rotator
with t... | astro-ph_SR |
GALEX J184559.8-413827: a new extreme helium star identified using SALT: A high-resolution spectrum of the helium-rich `hot subdwarf' GALEX
J184559.8-413827 (J1845-4138) obtained with SALT HRS demonstrates it to be the
first extreme helium (EHe) star to be discovered in nearly 40 years. A
quantitative analysis demonstr... | astro-ph_SR |
Driving Turbulence and Triggering Star Formation by Ionizing Radiation: We present high resolution simulations on the impact of ionizing radiation of
massive O-stars on the surrounding turbulent interstellar medium (ISM). The
simulations are performed with the newly developed software iVINE which
combines ionization wi... | astro-ph_SR |
Active red giants: close binaries versus single rapid rotators: The objective of this work is to determine what fraction of red-giant (RG)
stars shows photometric rotational modulation, and understand its origin. One
of the underlying questions is the role of close binarity in this population,
standing upon the fact th... | astro-ph_SR |
Eccentricity and Spin-Orbit Misalignment in Short-Period Stellar
Binaries as a Signpost of Hidden Tertiary Companions: Eclipsing binaries are observed to have a range of eccentricities and
spin-orbit misalignments (stellar obliquities). Whether such properties are
primordial, or arise from post-formation dynamical in... | astro-ph_SR |
The winds of young Solar-type stars in Coma Berenices and Hercules-Lyra: We present wind models of ten young Solar-type stars in the Hercules-Lyra
association and the Coma Berenices cluster aged around 0.26 Gyr and 0.58 Gyr
respectively. Combined with five previously modelled stars in the Hyades
cluster, aged 0.63 Gyr,... | astro-ph_SR |
Episodic Accretion on to Strongly Magnetic Stars: Some accreting neutron stars and young stars show unexplained episodic flares
in the form of quasi-periodic oscillations or recurrent outbursts. In a series
of two papers we present new work on an instability that can lead to episodic
outbursts when the accretion disc i... | astro-ph_SR |
Two-dimensional simulations of internal gravity waves in a 5 $M_{\odot}$
Zero-Age-Main-Sequence model: Main-sequence intermediate-mass stars present a radiative envelope that
supports internal gravity waves (IGWs). Excited at the boundary with the
convective core, IGWs propagate towards the stellar surface and are su... | astro-ph_SR |
Mode identification in three pulsating hot subdwarfs observed with TESS
satellite: We report on the detection of pulsations of three pulsating subdwarf B stars
observed by the TESS satellite and our results of mode identification in these
stars based on an asymptotic period relation. SB 459 (TIC 067584818), SB 815
(T... | astro-ph_SR |
The Vertical Current Approximation Nonlinear Force-Free Field Code -
Description, Performance Tests, and Measurements of Magnetic Energies
Dissipated in Solar Flares: In this work we provide an updated description of the Vertical Current
Approximation Nonlinear Force-Free Field (VCA-NLFFF) code, which is designed t... | astro-ph_SR |
Precise mass measurements for the double neutron star system J1829+2456: PSR J1829+2456 is a radio pulsar in a relativistic binary system with another
neutron star. It has a rotational period of 41 ms and a mildly eccentric ($e =
0.14$) 28-hr orbit. We have continued its observations with the Arecibo radio
telescope an... | astro-ph_SR |
Imaging Discovery of the Debris Disk Around HIP 79977: We present Subaru/HiCIAO H-band high-contrast images of the debris disk
around HIP 79977, whose pres- ence was recently inferred from an infrared
excess. Our images resolve the disk for the first time, allowing
characterization of its shape, size, and dust grain pr... | astro-ph_SR |
The Mass-Loss Induced Eccentric Kozai Mechanism: A New Channel for the
Production of Close Compact Object-Stellar Binaries: Over a broad range of initial inclinations and eccentricities an appreciable
fraction of hierarchical triple star systems with similar masses are
essentially unaffected by the Kozai-Lidov mechan... | astro-ph_SR |
Using Machine Learning Methods to Forecast If Solar Flares Will Be
Associated with CMEs and SEPs: Among the eruptive activity phenomena observed on the Sun, the most
technology threatening ones are flares with associated coronal mass ejections
(CMEs) and solar energetic particles (SEPs). Flares with associated CMEs a... | astro-ph_SR |
Magnetospherically driven optical and radio aurorae at the end of the
stellar main sequence: Aurorae are detected from all the magnetized planets in our Solar System,
including Earth. They are powered by magnetospheric current systems that lead
to the precipitation of energetic electrons into the high-latitude region... | astro-ph_SR |
Detailed computation of hot-plasma atomic spectra: We present recent evolutions of the detailed opacity code SCO-RCG which
combines statistical modelings of levels and lines with fine-structure
calculations. The code now includes the Partially-Resolved-Transition-Array
model, which allows one to replace a complex trans... | astro-ph_SR |
Observations of magnetic reconnection and particle acceleration
locations in solar coronal jets: We present a multi-wavelength analysis of two flare-related jets on November
13, 2014, using data from SDO/AIA, RHESSI, Hinode/XRT, and IRIS. Unlike most
coronal jets where hard X-ray (HXR) emissions are usually observed ... | astro-ph_SR |
Hubble Space Telescope Snapshot Survey for Resolved Companions of
Galactic Cepheids: Final Results: Cepheids in multiple systems provide information on the outcome of the
formation of massive stars. They can also lead to exotic end-stage objects.
This study concludes our survey of 70 galactic Cepheids using the {\it ... | astro-ph_SR |
Probing X-ray photoevaporative winds through their interaction with
ionising radiation in cluster environments: the case for X-ray proplyds: We show that if young low mass stars undergo vigorous X-ray driven disc
winds, these may be detected in clusters through their interaction with
ionising radiation from massive s... | astro-ph_SR |
Spicule Dynamics over Plage Region: We studied spicular jets over a plage area and derived their dynamic
characteristics using Hinode Solar Optical Telescope (SOT) high-resolution
images. The target plage region was near the west limb of the solar disk. This
location permitted us to study the dynamics of spicular jets ... | astro-ph_SR |
Resistive magnetohydrodynamic simulations of the ideal tearing mode: We study the linear and nonlinear evolution of the tearing instability on
thin current sheets by means of two-dimensional numerical simulations, within
the framework of compressible, resistive magnetohydrodynamics. In particular we
analyze the behavio... | astro-ph_SR |
Signature of mass supply to quiet coronal loops: Aims. The physical implication of large blue shift of Ne viii in the quiet
Sun region is investigated in this paper. Methods. We compare the significant
Ne viii blue shifts, which are visible as large blue patches on the
Doppler-shift map of a middlelatitude quiet-Sun re... | astro-ph_SR |
The first photometric investigation of the contact binary OQ Cam: The first charge-coupled device photometric light curves in B, V, R${_c}$,
and I${_c}$ bands of the short-period contact binary star OQ Cam are presented.
Through analyzing the light curves with the Wilson-Devinney code, it is found
that OQ Cam is a W-ty... | astro-ph_SR |
A Low-Mass Pre-Main-Sequence Eclipsing Binary in Lower Centaurus Crux
Discovered with TESS: We report the discovery of 2M1222-57 as a low-mass, pre-main-sequence (PMS)
eclipsing binary (EB) in the Lower Centaurus Crux (LCC) association for which,
using Gaia parallaxes and proper motions with a neural-net age estimato... | astro-ph_SR |
Lagrangian coherent structures in nonlinear dynamos: Turbulence and chaos play a fundamental role in stellar convective zones
through the transportof particles, energy and momentum, and in fast dynamos,
through the stretching, twisting and folding of magnetic flux tubes. A
particularly revealing way to describe turbule... | astro-ph_SR |
Discovery of a new photometric sub-class of faint and fast classical
novae: We present photometric and spectroscopic follow-up of a sample of
extragalactic novae discovered by the Palomar 60-inch telescope during a search
for "Fast Transients In Nearest Galaxies" (P60-FasTING). Designed as a fast
cadence (1-day) and ... | astro-ph_SR |
Sunspot umbra atmosphere from full Stokes inversion: Sunspots are prominent manifestations of the solar cycle and provide key
constraints for understanding its operation. Also, knowing internal structure
of sunspots allows us to gain insights on the energy transport in strong
magnetic fields and, thus, on the processes... | astro-ph_SR |
A JWST project on 47 Tucanae. Overview, photometry and early
spectroscopic results of M dwarfs, and observation of brown dwarfs: The James Webb Space Telescope (JWST) observations have been demonstrated to
be efficient in detecting globular clusters' (GCs) multiple stellar populations
in the low mass regime of M dwar... | astro-ph_SR |
Using ForeCAT Deflections and Rotations to Constrain the Early Evolution
of CMEs: To accurately predict the space weather effects of coronal mass ejection
(CME) impacts at Earth one must know if and when a CME will impact Earth, and
the CME parameters upon impact. Kay et al. (2015b) presents Forecasting a CME's
Alter... | astro-ph_SR |
Solar cycle variations of large frequency separations of acoustic modes:
Implications for asteroseismology: We have studied solar cycle changes in the large frequency separations that
can be observed in Birmingham Solar Oscillations Network (BiSON) data. The
large frequency separation is often one of the first output... | astro-ph_SR |
Suzaku observation of the transient X-ray pulsar GRO J1008-57: We report the timing and broad-band spectral properties of the Be transient
high mass X-ray binary pulsar GRO J1008-57 using a Suzaku observation in the
declining phase of its 2007 November-December outburst. Pulsations with a
period of 93.737 s were clearl... | astro-ph_SR |
Twelve years of spectroscopic monitoring in the Galactic Center: the
closest look at S-stars near the black hole: We study the young S-stars within a distance of 0.04 pc from the supermassive
black hole in the center of our Galaxy. Given how inhospitable the region is
for star formation, their presence is more puzzli... | astro-ph_SR |
Chemical Abundances in a Sample of Red Giants in the Open Cluster NGC
2420 from APOGEE: NGC 2420 is a $\sim$2 Gyr-old well-populated open cluster that lies about 2
kpc beyond the solar circle, in the general direction of the Galactic
anti-center. Most previous abundance studies have found this cluster to be
mildly me... | astro-ph_SR |
The 26 December 2001 Solar Eruptive Event Responsible for GLE63. II.
Multi-Loop Structure of Microwave Sources in a Major Long-Duration flare: Analysis of the observations of the SOL2001-12-26 event related to
ground-level-event GLE63, including microwave spectra and images from NoRH at
17 and 34 GHz, SSRT at 5.7 GHz... | astro-ph_SR |
NSE abundance data: Novel method of calculating Nuclear Statistical Equilibrium is presented.
Basic equations are carefully solved using arbitrary precision arithmetic.
Special interpolation procedure is then used to retrieve all abundances using
tabulated results for neutrons and protons, together with basic nuclear d... | astro-ph_SR |
Identification of red supergiants in nearby galaxies with mid-IR
photometry: The role of episodic mass loss in massive star evolution is one of the most
important open questions of current stellar evolution theory. Episodic mass
loss produces dust and therefore causes evolved massive stars to be very
luminous in the ... | astro-ph_SR |
Fine structures of radio bursts from flare star AD Leo with FAST
observations: Radio bursts from nearby active M-dwarfs have been frequently reported and
extensively studied in solar or planetary paradigms. Whereas, their
sub-structures or fine structures remain rarely explored despite their
potential significance in... | astro-ph_SR |
Alfvén wave experiments with liquid rubidium in a pulsed magnetic
field: Magnetic fields are key ingredients for heating the solar corona to
temperatures of several million Kelvin. A particularly important region with
respect to this is the so-called magnetic canopy below the corona, where sound
and Alfv\'en waves ha... | astro-ph_SR |
Empirical 2MASS-WFC3/IR filter transformations from synthetic photometry: Near-infrared bandpasses on spaceborne observatories diverge from their
ground-based counterparts as they are free of atmospheric telluric absorption.
Available transformations between respective filter systems in the literature
rely on theoretic... | astro-ph_SR |
Jeans Instability in a viscoelastic fluid: The well known Jeans instability is studied for a viscoelastic, gravitational
fluid using generalized hydrodynamic equations of motions. It is found that the
threshold for the onset of instability appears at higher wavelengths in a
viscoelastic medium. Elastic effects playing ... | astro-ph_SR |
HD 51106 and HD 50747: an ellipsoidal binary and a triple system
observed with CoRoT: We present an analysis of the observations of HD 51106 and HD 50747 by the
satellite CoRoT, obtained during its initial run, and of the spectroscopic
preparatory observations.
AIMS: We complete an analysis of the light curve, extr... | astro-ph_SR |
Luminosities of Carbon-rich Asymptotic Giant Branch stars in the Milky
Way: Stars evolving along the Asymptotic Giant Branch can become Carbon-rich in
the final part of their evolution. They replenish the inter-stellar medium with
nuclear processed material via strong radiative stellar winds. The
determination of the... | astro-ph_SR |
First axion bounds from a pulsating helium-rich white dwarf star: The Peccei-Quinn mechanism proposed to solve the CP problem of Quantum
Chromodynamics has as consequence the existence of axions, hypothetical weakly
interacting particles whose mass is constrained to be on the sub-eV range. If
these particles exist and ... | astro-ph_SR |
On modeling ICME cross-sections as static MHD columns: Solar coronal mass ejections are well known to expand as they propagate
through the heliosphere. Despite this, their cross-sections are usually modeled
as static plasma columns within the magnetohydrodynamics (MHD) framework. We
test the validity of this approach u... | astro-ph_SR |
An abundance analysis from the STIS-HST UV spectrum of the non-magnetic
Bp star HR 6000: The sharp-line spectrum of the Bp star HR 6000 has peculiarities that
distinguish it from those of the HgMn stars with which it is sometimes
associated. The position of the star close to the center of the Lupus 3
molecular cloud,... | astro-ph_SR |
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 ("... | astro-ph_SR |
Evidence of a Mira-like tail and bow shock about the semi-regular
variable V CVn from four decades of polarization measurements: Polarization is a powerful tool for understanding stellar atmospheres and
circumstellar environments. Mira and semi-regular variable stars have been
observed for decades and some are known ... | astro-ph_SR |
Far Ultraviolet Spectroscopy of Three Long Period Nova-Like Variables: We have selected three nova-like variables at the long period extreme of
nova-like orbital periods: V363 Aur, RZ Gru and AC Cnc, all with IUE archival
far ultraviolet spectra. All are UX UMa type nova-like variables and all have
$P_{orb} > 7$h. V363... | astro-ph_SR |
Chemical Composition of the Atmospheres of Red Giants with High Space
Velocities: The results of a comparative analysis of the elemental abundances in the
atmospheres of 14 red giants with high Galactic space velocities are presented.
For almost all of the chemical elements considered, the their abundance trends
with... | astro-ph_SR |
MESA Models of the Evolutionary State of the Interacting Binary epsilon
Aurigae: Using MESA code (Modules for Experiments in Stellar Astrophysics, version
9575), an evaluation was made of the evolutionary state of the epsilon Aurigae
binary system (HD 31964, F0Iap + disk). We sought to satisfy several
observational c... | astro-ph_SR |
IRTF Observations of White Dwarfs with Possible Near-Infrared Excess: Near-infrared photometry and spectroscopy is obtained for a heterogeneous
sample of nearby white dwarfs with possible excess flux as identified primarily
in the Two Micron All Sky Survey. Among the sample of 43 stars are a number of
white dwarfs that... | astro-ph_SR |
Astro2020 Science White Paper: gravity-wave asteroseismology of
intermediate- and high-mass stars: The evolution of a star is driven by the physical processes in its interior
making the theory of stellar structure and evolution the most crucial
ingredient for not only stellar evolution studies, but any field of astro... | astro-ph_SR |
Magnetoclinicity Instability: In strongly compressible magnetohydrodynamic turbulence, obliqueness between
the large-scale density gradient and magnetic field gives an electromotive
force mediated by density variance (intensity of density fluctuation). This
effect is named ``magnetoclinicity'', and is expected to play ... | astro-ph_SR |
Early Time Light Curves of Type Ia Supernovae Observed with TESS: We present early time light curves of Type Ia supernovae observed in the
first six sectors of TESS data. Ten of these supernovae were discovered by
ASAS-SN, seven by ATLAS, six by ZTF, and one by \textit{Gaia}. For nine SNe
with sufficient dynamic range ... | astro-ph_SR |
Keplerian frequency of uniformly rotating neutron stars and quark stars: We calculate Keplerian (mass shedding) configurations of rigidly rotating
neutron stars and quark stars with crusts. We check the validity of empirical
formula for Keplerian frequency, f_K, proposed by Lattimer & Prakash, f_K(M)=C
(M/M_sun)^1/2 (R... | astro-ph_SR |
Predicting the Magnetic Fields of a Stealth CME Detected by Parker Solar
Probe at 0.5 AU: Stealth coronal mass ejection (CMEs) are eruptions from the Sun that are not
associated with appreciable low-coronal signatures. Because they often cannot
be linked to a well-defined source region on the Sun, analysis of their i... | astro-ph_SR |
The Rich Circumstellar Chemistry of SMP LMC 11: Carbon-rich evolved stars from the asymptotic giant branch to the planetary
nebula phase are characterized by a rich and complex carbon chemistry in their
circumstellar envelopes. A peculiar object is the preplanetary nebula SMP LMC
11, whose Spitzer-IRS spectrum shows re... | astro-ph_SR |
Photometric and spectroscopic study of the intermediate-age open cluster
NGC 2355: In this paper we analyse the evolutionary status and properties of the old
open cluster NGC 2355, located in the Galactic anticentre direction, as a part
of the long term programme BOCCE. NGC 2355 was observed with LBC@LBT using the
Be... | astro-ph_SR |
Spectroscopic Studies of 30 Short-period Cataclysmic Variable Stars, and
Remarks on the Evolution and Population of Similar Objects: We present spectroscopy and orbital periods Porb for 30 apparently
non-magnetic cataclysmic binaries with periods below about 3 hours, nearly all
of which are dwarf novae, mostly of the... | astro-ph_SR |
The formation of IRIS diagnostics VIII. IRIS observations in the C II
133.5 nm multiplet: The C II 133.5 nm multiplet has been observed by NASA's Interface Region
Imaging Spectrograph (IRIS) in unprecedented spatial resolution. The aims of
this work are to characterize these new observations of the C II lines, place
... | astro-ph_SR |
The orbital and superhump periods of the SU UMa-type dwarf nova V1212
Tauri: We report CCD photometry of the superoutburst of the dwarf nova V1212 Tau
obtained during 2011 January and February. The outburst amplitude was at least
6 magnitudes and it lasted at least 12 days. Three distinct superhump regimes
were obser... | astro-ph_SR |
3D Stellar Reddening Map from 2MASS Photometry: An Improved Version: An improved version of the 3D stellar reddening map in a space with a radius
of 1200 pc around the Sun and within 600 pc of the Galactic midplane is
presented. As in the previous 2010 and 2012 versions of the map, photometry
with an accuracy better th... | astro-ph_SR |
Pulsating Components in Binary and Multiple Stellar Systems --- A
Catalog of Oscillating Binaries: We present an up-to-date catalog of pulsating binaries, i.e. the binary and
multiple stellar systems containing pulsating components, along with a
statistics on them. Compared to the earlier compilation by Soydugan et
a... | astro-ph_SR |
The G-O Rule and Waldmeier Effect in the Variations of the Numbers of
Large and Small Sunspot Groups: We have analysed the combined Greenwich and Solar Optical Observing Network
(SOON) sunspot group data during the period of 1874-2011 and determined
variations in the annual numbers (counts) of the small, large and bi... | astro-ph_SR |
On effects of surface bipolar magnetic regions on the convection zone
dynamo: We investigate the effect of the surface bipolar magnetic regions (BMR) on
the large-scale dynamo distributed in the bulk of the convection zone. The
study employs the nonlinear 3D mean-field dynamo model. We model the emergence
of the BMR ... | astro-ph_SR |
Discovery of Radial Spectral Hardening in the Hot Bubble of Planetary
Nebula BD+30 3639 with Median Energy Imaging: We introduce a new imaging analysis technique to study the spatial
distribution of the X-ray emission from the hot bubble of planetary nebula
BD+30 3639. Hot bubble emission is typically photon-starved,... | astro-ph_SR |
The data center for the Spectrometer and Telescope for Imaging X-rays
(STIX) onboard Solar Orbiter: The Spectrometer and Telescope for Imaging X-rays (STIX) on board Solar
Orbiter observes solar X-ray emission in the range of 4 – 150 keV and
produces spectra and images of solar flares over a wide range of flare... | astro-ph_SR |
Population of post-nova supersoft X-ray sources: Novae undergo a supersoft X-ray phase of varying duration after the optical
outburst. Such transient post-nova supersoft X-ray sources (SSSs) are the
majority of the observed SSSs in M31. In this paper, we use the post-nova
evolutionary models of Wolf et al. to compute t... | astro-ph_SR |
The planetary nebula population of M33 and its metallicity gradient: A
look into the galaxy's distant past: The Planetary Nebula (PN) population of M33 is studied via multi-fiber
spectroscopy with Hectospec at the MMT. In this paper we present the spectra of
102 PNe, whereas plasma diagnostic and chemical abundances ... | astro-ph_SR |
SN 2008gz - most likely a normal type IIP event: We present BV RI photometric and low-resolution spectroscopic investigation
of a type II core-collapse supernova (SN) 2008gz, which occurred in a star
forming arm and within a half-light radius (solar metallicity region) of a
nearby spiral galaxy NGC 3672. The SN event w... | astro-ph_SR |
Distances to Recent Near-Earth Supernovae From Geological and Lunar 60Fe: Near-Earth supernova blasts which engulf the solar system have left traces of
their ejecta in the geological and lunar records. There is now a wealth of data
on live radioactive ${}^{60}$Fe pointing to a supernova at 3 Myr ago, as well
as the rec... | astro-ph_SR |
Power-law statistics and stellar rotational velocities in the Pleiades: In this paper we will show that, the non-gaussian statistics framework based
on the Kaniadakis statistics is more appropriate to fit the observed
distributions of projected rotational velocity measurements of stars in the
Pleiades open cluster. To ... | astro-ph_SR |
GYRE: A New Open-Source Stellar Oscillation Code: We introduce GYRE, a new open-source stellar oscillation code which solves
the adiabatic/non-adiabatic pulsation equations using a novel Magnus Multiple
Shooting (MMS) numerical scheme. The code has a global error scaling of up to
6th order in the grid spacing, and can ... | astro-ph_SR |
Local Helioseismology of Sunspots: Current Status and Perspectives
(Invited Review): Mechanisms of the formation and stability of sunspots are among the
longest-standing and intriguing puzzles of solar physics and astrophysics.
Sunspots are controlled by subsurface dynamics hidden from direct observations.
Recently, ... | astro-ph_SR |
Magnetic imprints of eruptive and non-eruptive Solar flares as observed
by Solar Dynamics Observatory: The abrupt and permanent changes of photospheric magnetic field in the
localized regions of active regions during solar flares called magnetic
imprints (MIs), have been observed for the past nearly three decades. Th... | astro-ph_SR |
Characterisation of the turbulent electromotive force and its
magnetically-mediated quenching in a global EULAG-MHD simulation of solar
convection: We perform a mean-field analysis of the EULAG-MHD millenium simulation of
global magnetohydrodynamical convection presented in Passos et al. 2014. The
turbulent electro... | astro-ph_SR |
Heavy element abundances in planetary nebulae: A theorist's perspective: The determination of heavy element abundances from planetary nebula (PN)
spectra provides an exciting opportunity to study the nucleosynthesis occurring
in the progenitor asymptotic giant branch (AGB) star. We perform
post-processing calculations ... | astro-ph_SR |
Numerical methods for solution of the stochastic differential equations
equivalent to the non-stationary Parker's transport equation: We derive the numerical schemes for the strong order integration of the set
of the stochastic differential equations (SDEs) corresponding to the
non-stationary Parker transport equatio... | astro-ph_SR |
Fundamental parameters of Ap-star HD 108662: We present the results of a self-consistent spectroscopic analysis of the
atmosphere of Ap-star HD 108662 based on high resolution spectrum and low
resolution spectrophotometric observations. Magnetic field effects, such as
Zeeman broadening and polarized line formation, wer... | astro-ph_SR |
Disk-Driven Rotating Bipolar Outflow in Orion Source I: One of the outstanding problems in star-formation theory concerns the
transfer of angular momentum such that mass can accrete onto a newly born young
stellar object (YSO). From a theoretical standpoint, outflows and jets are
predicted to play an essential role in ... | astro-ph_SR |
Constraining the amplitude of turbulence in solar corona using
observations of angular broadening of radio sources: The angular broadening of compact radio sources observed through a medium
having turbulent density irregularities is usually estimated using the phase
structure function. We employ an exact formulation ... | astro-ph_SR |
Flare Rates, Rotation Periods. and Spectroscopic Activity Indicators of
a Volume-Complete Sample of Mid-to-Late M dwarfs within 15 Parsecs: We present a study of flare rates, rotation periods, and spectroscopic
activity indicators of 125 single stars within 15 parsecs and with masses
between 0.1$-$0.3 $M_\odot$ obser... | astro-ph_SR |
Monotonicity of the cores of massive stars: Massive stars are linked with diverse astronomical processes and objects
including star formation, supernovae and their remnants, cosmic rays,
interstellar media, and galaxy evolution. Understanding their properties is of
primary importance for modern astronomy, and finding s... | astro-ph_SR |
Shaken and stirred: the effects of turbulence and rotation on disc and
outflow formation during the collapse of magnetised molecular cloud cores: We present the results of eighteen magnetohydrodynamical calculations of the
collapse of a molecular cloud core to form a protostar. Some calculations
include radiative tra... | astro-ph_SR |
A Closer Look at the Alpha Persei Coronal Conundrum: A ROSAT survey of the Alpha Per open cluster in 1993 detected its brightest
star, mid-F supergiant Alpha Persei: the X-ray luminosity and spectral hardness
were similar to coronally active late-type dwarf members. Later, in 2010, a
Hubble Cosmic Origins Spectrograph ... | astro-ph_SR |
A comprehensive study of young B stars in NGC 2264: I. Space photometry
and asteroseismology: Space photometric time series of the most massive members of the young open
cluster NGC 2264 allow us to study their different sources of variability down
to the millimagnitude level and permits a search for Slowly Pulsating... | astro-ph_SR |
Diagnostics of non-thermal distributions in solar flare spectra observed
by RESIK and RHESSI: We focus on the non-thermal components of the electron distribution in the
keV range and analyse high-energy resolution X-ray spectra detected by RESIK
and RHESSI for three solar flares.In the 2-4 keV range we assume that th... | astro-ph_SR |
The floor in the interplanetary magnetic field: Estimation on the basis
of relative duration of ICME observations in solar wind during 1976-2000: To measure the floor in interplanetary magnetic field and estimate the time-
invariant open magnetic flux of Sun, it is necessary to know a part of magnetic
field of Sun ca... | astro-ph_SR |
Determination of the inclination of the multi-planet hosting star HR8799
using asteroseismology: Direct imaging of the HR8799 system was a major achievement in the study of
exoplanets. HR8799 is a $\gamma$\,Doradus variable and asteroseismology can
provide an independent constraint on the inclination. Using 650 high
... | astro-ph_SR |
Two-step evolution of a rising flux rope resulting in a confined solar
flare: Combining the Solar Dynamics Observatory and the New Vacuum Solar Telescope
observations, we study a confined flare triggered by a rising flux rope within
the trailing sunspots of active region 12733. The flux rope lying above the
sheared p... | astro-ph_SR |
Radiation-pressure-driven dust waves inside bursting interstellar
bubbles: Massive stars drive the evolution of the interstellar medium through their
radiative and mechanical energy input. After their birth, they form bubbles of
hot gas surrounded by a dense shell. Traditionally, the formation of bubbles is
explained... | astro-ph_SR |
The physics of neutron stars: Topical problems in the physics of and basic facts about neutron stars are
reviewed. The observational manifestations of neutron stars, their core and
envelope structure, magnetic fields, thermal evolution, and masses and radii
are briefly discussed, along with the underlying microphysics. | astro-ph_SR |
Statistics of the two-point cross-covariance function of solar
oscillations: Context: The cross-covariance of solar oscillations observed at pairs of
points on the solar surface is a fundamental ingredient in time-distance
helioseismology. Wave travel times are extracted from the cross-covariance
function and are use... | astro-ph_SR |
An interesting candidate for isolated massive star formation in the
Small Magellanic Cloud: The region of the Small Magellanic Cloud (SMC) with which this paper is
concerned contains the highest concentration of IRAS/Spitzer sources, H I
emission, and molecular clouds in this neighboring galaxy. However very few
stud... | astro-ph_SR |
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