Unnamed: 0 int64 0 41k | title stringlengths 4 274 | category stringlengths 5 18 | summary stringlengths 22 3.66k | theme stringclasses 8
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6,300 | Photospheric and Subphotospheric Dynamics of Emerging Magnetic Flux | astro-ph.SR | Magnetic fields emerging from the Sun's interior carry information about
physical processes of magnetic field generation and transport in the convection
zone. Soon after appearance on the solar surface the magnetic flux gets
concentrated in sunspot regions and causes numerous active phenomena on the
Sun. This paper dis... | physics |
6,301 | Observational Evidence for Coronal Twisted Flux Rope | astro-ph.SR | Multi-instrument data sets of NOAA AR10938 on Jan. 16, 2007, (e.g.,
{\emph{Hinode}}, {\it{STEREO}}, {\it{GOES}}, {\it{MLSO}} and {\it{ISOON}}
H$\alpha$) are utilized to study the fine structure and evolution of a magnetic
loop system exhibiting multiple crossing threads, whose arrangement and
individual shapes are very... | physics |
6,302 | On active region loops: Hinode/EIS observations | astro-ph.SR | Coronal loops are fundamental building blocks of the solar active regions and
the corona. Therefore, a clear understanding of the physics of coronal loops
will help us understand the physics of active region heating in particular and
coronal heating in general. This requires a precise measurement of physical
quantities... | physics |
6,303 | Relativistic Lidov-Kozai resonance in binaries | astro-ph.SR | We consider the secular dynamics of a binary and a planet in terms of
non-restricted, hierarchical three-body problem, including the general
relativity corrections to the Newtonian gravity. We determine regions in the
parameter space where the relativistic corrections may be important for the
long-term dynamics. We try... | physics |
6,304 | Polarization of FIR emission from T Tauri Disks | astro-ph.SR | Recent observation of 850 micron sub-mm polarization from T Tauri disks opens
up the possibility of studying magnetic field structure within protostellar
disks. The degree of polarization is around 3 % and the direction of
polarization is perpendicular to the disk. Since thermal emission from dust
grains dominates the ... | physics |
6,305 | Modeling the RV and BVS of active stars | astro-ph.SR | We present a method of modeling the radial velocity (RV) measurements which
can be useful in searching for planets hosted by chromospherically active
stars. We assume that the observed RV signal is induced by the reflex motion of
a star as well as by distortions of spectral line profiles, measured by the
Bisector Veloc... | physics |
6,306 | NLTE models of line-driven stellar winds III. Influence of X-ray radiation on wind structure of O stars | astro-ph.SR | We study the influence of X-rays on the wind structure of selected O stars.
For this purpose we use our non-local thermodynamic equilibrium (NLTE) wind
code with inclusion of additional artificial source of X-rays, assumed to
originate in the wind shocks.
We show that the influence of shock X-ray emission on wind mas... | physics |
6,307 | Advances in theory and simulations of large-scale dynamos | astro-ph.SR | Recent analytical and computational advances in the theory of large-scale
dynamos are reviewed. The importance of the magnetic helicity constraint is
apparent even without invoking mean-field theory. The tau approximation yields
expressions that show how the magnetic helicity gets incorporated into
mean-field theory. T... | physics |
6,308 | Magnetism of Herbig Ae/Be stars | astro-ph.SR | Observations of magnetic fields of stars at the pre-main sequence phase can
provide important new insights into the complex physics of the late stages of
star formation. This is especially true at intermediate stellar masses, where
magnetic fields are strong and globally organised, and therefore most amenable
to direct... | physics |
6,309 | Chirality of Intermediate Filaments and Magnetic Helicity of Active Regions | astro-ph.SR | Filaments which form either between or around active regions (ARs) are called
intermediate filaments. In spite of various theoretical studies, the origin of
the chirality of filaments is still uncovered. We investigated how intermediate
filaments are related to their associated ARs, especially from the point of
view of... | physics |
6,310 | The relations between main stellar parameters | astro-ph.SR | The relations between masses, radii and surface temperatures of stars are
considered. It is shown that calculated values of these relations are in a
satisfactory agreement with measuring data. | physics |
6,311 | Uncovering the Outflow Driven by the Brown Dwarf LS-RCr A1: H-alpha as a Tracer of Outflow Activity in Brown Dwarfs | astro-ph.SR | It is now apparent that classical T Tauri-like outflows commonly accompany
the formation of young brown dwarfs. To date two optical outflows have been
discovered and results presented in this paper increase this number to three.
Using spectro-astrometry the origin of the LS-RCrA 1 forbidden emission lines
in a blue-shi... | physics |
6,312 | Turbulence and Magnetic Field Amplification in Supernova Remnants: Interactions Between A Strong Shock Wave and Multi-Phase Interstellar Medium | astro-ph.SR | We examine MHD simulations of the propagation of a strong shock wave through
the interstellar two-phase medium composed of small-scale cloudlets and diffuse
warm neutral medium in two-dimensional geometry. The pre-shock two-phase medium
is provided as a natural consequence of the thermal instability that is
expected to... | physics |
6,313 | On the Physical Interpretation of Malyshkin's (2008) Model of Resistive Hall-MHD Reconnection | astro-ph.SR | A simple Sweet--Parker-like model for the electron current layer in resistive
Hall magnetohydrodynamic (MHD) reconnection is presented, with the focus on the
collisionless limit. The derivation readily recovers the main results obtained
recently by Malyshkin [PRL, 101, 225001 (2008)] and others, but is much quicker
and... | physics |
6,314 | An Infrared Census of Star Formation in the Horsehead Nebula | astro-ph.SR | At ~ 400 pc, the Horsehead Nebula (B33) is the closest radiatively-sculpted
pillar to the Sun, but the state and extent of star formation in this structure
is not well understood. We present deep near-infrared (IRSF/SIRIUS JHKs) and
mid-infrared (Spitzer/IRAC) observations of the Horsehead Nebula in order to
characteri... | physics |
6,315 | Photometric campaign on massive stars in the open cluster NGC 5617 | astro-ph.SR | A campaign on the open cluster NGC 5617 was organized in order to
characterize the pulsations and to better understand the internal structure of
its stars. The variability of the cluster members was never studied before. We
present the observations taken and an up-to-date analysis of the obtained time
series, especiall... | physics |
6,316 | Asteroseismology of massive stars in the young open cluster NGC 884: a status report | astro-ph.SR | To improve our comprehension of the beta Cephei stars, we set up a
photometric multi-site campaign on the open cluster NGC 884 (Chi Persei).
Thirteen telescopes joined the 2005-2007 campaign which resulted in almost
78000 CCD frames. We present an up-to-date status of the analysis of these
data, in which several intere... | physics |
6,317 | Empirical chemical stratifications in magnetic Ap stars: questions of uniqueness | astro-ph.SR | Over the last decades, modelling of the inhomogeneous vertical abundance
distributions of various chemical elements in magnetic peculiar A-type has
largely relied on simple step-function approximations. In contrast, the
recently introduced regularised vertical inverse problem (VIP) is not based on
parametrised stratifi... | physics |
6,318 | A first orbital solution for the very massive 30 Dor main-sequence WN6h+O binary R145 | astro-ph.SR | We report the results of a spectroscopic and polarimetric study of the
massive, hydrogen-rich WN6h stars R144 (HD 38282 = BAT99-118 = Brey 89) and
R145 (HDE 269928 = BAT99-119 = Brey 90) in the LMC. Both stars have been
suspected to be binaries by previous studies (R144: Schnurr et al. 2008b; R145:
Moffat 1989). We hav... | physics |
6,319 | Eta Carinae across the 2003.5 Minimum: Analysis in the visible and near infrared spectral region | astro-ph.SR | We present an analysis of the visible through near infrared spectrum of Eta
Carinae and its ejecta obtained during the "Eta Carinae Campaign with the UVES
at the ESO VLT". This is a part of larger effort to present a complete Eta
Carinae spectrum, and extends the previously presented analyses with the
HST/STIS in the U... | physics |
6,320 | The pre- versus post-main sequence evolutionary phase of B[e] stars: Constraints from 13CO band emission | astro-ph.SR | Many galactic B[e] stars suffer from improper distance determinations, which
make it difficult to distinguish between a pre- and post-main sequence
evolutionary phase on the basis of luminosity arguments. In addition, these
stars have opaque circumstellar material, obscuring the central star, so that
no detailed surfac... | physics |
6,321 | Spectroscopic Evidence for Gas Infall in GF9-2 | astro-ph.SR | We present spectroscopic evidence for infall motion of gas in the natal cloud
core harboring an extremely young low-mass protostar GF9-2. We previously
discussed that the ongoing collapse of the GF9-2 core has agreement with the
Larson-Penston-Hunter (LPH) theoretical solution for the gravitational collapse
of a core (... | physics |
6,322 | Magnetic pinch-type instability in stellar radiative zones | astro-ph.SR | The solar tachocline is shown as hydrodynamically stable against
nonaxisymmetric disturbances if it is true that no cos^{4}\theta term exists in
its rotation law. We also show that the toroidal field of 200 Gauss amplitude
which produces the tachocline in the magnetic theory of Ruediger & Kitchatinov
(1997) is stable a... | physics |
6,323 | Discovery of two distinct red clumps in NGC419: a rare snapshot of a cluster at the onset of degeneracy | astro-ph.SR | Colour-magnitude diagrams (CMD) of the SMC star cluster NGC419, derived from
HST/ACS data, reveal a well-delineated secondary clump located below the
classical compact red clump typical of intermediate-age populations. We
demonstrate that this feature belongs to the cluster itself, rather than to the
underlying SMC fie... | physics |
6,324 | Formation of Transient Coronal Holes during Eruption of a Quiescent Filament and its Overlying Sigmoid | astro-ph.SR | 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 overlying the filament
channel observed by the $\emph{GOES-12}$ SXR Imager (SXI), and led to the
eruption of ... | physics |
6,325 | Evolution and Nucleosynthesis of Extremely Metal Poor & Metal-Free Low- and Intermediate-Mass Stars I: Stellar Yield Tables and the CEMPs | astro-ph.SR | [Abridged] We calculate the structural evolution and nucleosynthesis of a
grid of models covering the metallicity range: -6.5 < [Fe/H] < -3.0 (plus Z=0),
and mass range: 0.85 < M < 3.0 Msun, amounting to 20 stars in total. In this
paper, the first of a series describing and analysing this large data set, we
present the... | physics |
6,326 | The redshifted network contrast of transition region emission | astro-ph.SR | Aims: We study the VUV emission of the quiet Sun and the net redshift of
transition region lines in the SUMER spectral range. We aim at establishing a
link with atmospheric processes and interpreting the observed downflow as the
most evident part of the prevailing global coronal mass transport. Methods: We
rank and arr... | physics |
6,327 | A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And XV and And XVI | astro-ph.SR | We present the results of a spectroscopic survey of the recently discovered
M31 satellites And XV and And XVI, lying at projected distances from the centre
of M31 of 93 and 130 kpc respectively. These satellites lie to the South of
M31, in regions of the stellar halo which wide field imaging has revealed as
relative vo... | physics |
6,328 | Solar and planetary dynamos: comparison and recent developments | astro-ph.SR | While obviously having a common root, solar and planetary dynamo theory have
taken increasingly divergent routes in the last two or three decades, and there
are probably few experts now who can claim to be equally versed in both.
Characteristically, even in the fine and comprehensive book "The magnetic
Universe" (Rudig... | physics |
6,329 | The Density of Coronal Null Points from Hinode and MDI | astro-ph.SR | Magnetic null points can be located numerically in a potential field
extrapolation or their average density can be estimated from the Fourier
spectrum of a magnetogram. We use both methods to compute the null point
density from a quiet Sun magnetogram made with Hinode's NFI and from
magnetograms from SOHO's MDI in both... | physics |
6,330 | Period Changes of LMC Cepheids in the OGLE and MACHO Data | astro-ph.SR | Pulsation period of Cepheids should change as stars evolve through the
instability strip. Rates of these changes found by other authors based on the
decades-long O-C diagrams show rather good agreement with theoretical
predictions. We have checked the variability on the scale of a few years on the
data recently publish... | physics |
6,331 | IPHAS A-type Stars with Mid-IR Excesses in Spitzer Surveys | astro-ph.SR | We have identified 17 A-type stars in the Galactic Plane that have mid-IR
excesses at 8 micron. From the observed colors in the (r'-H_alpha)-(r'-i')
plane, we first identified 23050 early A-type main sequence (MS) star
candidates in the Isaac Newton Photometric H-Alpha Survey (IPHAS) point source
database that are loca... | physics |
6,332 | Spectroscopic binaries among Hipparcos M giants I. Data, orbits, and intrinsic variations | astro-ph.SR | This paper is a follow-up of the vast effort to collect radial velocity data
for stars belonging to the Hipparcos survey. We aim at extending the orbital
data available for binaries with M giant primaries. The data will be used in
the companion papers of this series to (i) derive the binary frequency among M
giants and... | physics |
6,333 | Spectroscopic binaries among Hipparcos M giants II. Binary frequency | astro-ph.SR | This paper is the second one in a series devoted to the study of properties
of binaries involving M giants. The binary frequency of field M giants is
derived and compared with the binary fraction of K giants. Diagrams of the
CORAVEL spectroscopic parameter Sb (measuring the average line-width) vs.
radial-velocity stand... | physics |
6,334 | Spectroscopic binaries among Hipparcos M giants III. The eccentricity-period diagram and mass-transfer signatures | astro-ph.SR | This paper is the third one in a series devoted to studying the properties of
binaries involving M giants. We use a new set of orbits to construct the first
(e-logP) diagram of an extensive sample of M giant binaries, to obtain their
mass-function distribution, and to derive evolutionary constraints for this
class of b... | physics |
6,335 | Polarization observations of 100 pulsars at 774 MHz by the Green Bank Telescope | astro-ph.SR | We report on polarimetric observations of 100 pulsars centered on 774 MHz,
made using the Green Bank Telescope, presenting their polarization profiles and
polarized flux densities and comparing them with previous observations when
possible. For 67 pulsars, these are the first such measurements made.
Polarization profil... | physics |
6,336 | Supersonic Cloud Collision-II | astro-ph.SR | In this second paper of the sequel of two papers, we further investigate the
problem of molecular cloud (MC) collision. Anathpindika (2009) (hereafter paper
I) considered highly supersonic cloud collisions and examined the effect of
bending and shearing instabilities on the shocked gas slab. We now consider
moderately ... | physics |
6,337 | The beat Cepheids in the Magellanic Clouds: an analysis from the EROS-2 database | astro-ph.SR | A number of microlensing dark-matter surveys have produced tens of millions
of light curves of individual background stars. These data provide an
unprecedented opportunity for systematic studies of whole classes of variable
stars and their host galaxies. We aim to use the EROS-2 survey of the
Magellanic Clouds to detec... | physics |
6,338 | Plasma Magnetosphere Formation Around Oscillating Magnetized Neutron Stars | astro-ph.SR | The notion of death line of rotating pulsars is applied to model of
oscillating neutron stars. It is shown that the magnetosphere of typical
non-rotating oscillating stars may not contain secondary plasma to support the
generation of radio emission in the region of open field lines of plasma
magnetosphere. | physics |
6,339 | Search for sdB/WD pulsators in the Kepler FOV | astro-ph.SR | In this article we present the preliminary results of an observational search
for subdwarf B and white dwarf pulsators in the Kepler field of view, performed
using the DOLORES camera attached to the 3.6m Telescopio Nazionale Galileo
(TNG). | physics |
6,340 | Cold gas as an ice diagnostic toward low mass protostars | astro-ph.SR | Up to 90% of the chemical reactions during star formation occurs on ice
surfaces, probably including the formation of complex organics. Only the most
abundant ice species are however observed directly by infrared spectroscopy.
This study aims to develop an indirect observational method of ices based on
non-thermal ice ... | physics |
6,341 | Zero Sound in Neutron Stars with Dense Quark Matter under Strong Magnetic Fields | astro-ph.SR | We study a neutron star with a quark matter core under extremely strong
magnetic fields. We investigate the possibility of an Urca process as a
mechanism for the cooling of such a star. We found that apart from very
particular cases, the Urca process cannot occur. We also study the stability of
zero sound modes under t... | physics |
6,342 | The HYPERMUCHFUSS Campaign -- an undiscovered high velocity population | astro-ph.SR | We present an overview and a status report of HYPERMUCHFUSS (HYPER velocity
or Massive Unseen Companions of Hot Faint Underluminious Stars Survey) aiming
at the detection of a population of high velocity subluminous B stars and white
dwarfs. The first class of targets consists of hot subdwarf binaries with
massive comp... | physics |
6,343 | Pulsar spin-velocity alignment from single and binary neutron star progenitors | astro-ph.SR | The role of binary progenitors of neutron stars in the apparent distribution
of space velocities and spin-velocity alignment observed in young pulsars is
studied. A Monte-Carlo synthesis of pulsar population from single and binary
stars with different assumptions about the NS natal kick model (direction
distribution, a... | physics |
6,344 | Active region transition region loop populations and their relationship to the corona | astro-ph.SR | The relationships among coronal loop structures at different temperatures is
not settled. Previous studies have suggested that coronal loops in the core of
an active region are not seen cooling through lower temperatures and therefore
are steadily heated. If loops were cooling, the transition region would be an
ideal t... | physics |
6,345 | Cyclic Variability of the Circumstellar Disc of the Be Star $ζ$ Tau. II. Testing the 2D Global Disc Oscillation Model | astro-ph.SR | Aims. In this paper we model, in a self-consistent way, polarimetric,
photometric, spectrophotometric and interferometric observations of the
classical Be star $\zeta$ Tauri. Our primary goal is to conduct a critical
quantitative test of the global oscillation scenario. Methods. We have carried
out detailed three-dimen... | physics |
6,346 | Numerical Simulations of Magnetized Winds of Solar-Like Stars | astro-ph.SR | We investigate magnetized solar-like stellar winds by means of
self-consistent three-dimensional (3D) magnetohydrodynamics (MHD) numerical
simulations. We analyze winds with different magnetic field intensities and
densities as to explore the dependence on the plasma-beta parameter. By solving
the fully ideal 3D MHD eq... | physics |
6,347 | Automated Detection of EUV Polar Coronal Holes During Solar Cycle 23 | astro-ph.SR | A new method for automated detection of polar coronal holes is presented.
This method, called perimeter tracing, uses a series of 171, 195, and 304 \AA\
full disk images from the Extreme ultraviolet Imaging Telescope (EIT) on SOHO
over solar cycle 23 to measure the perimeter of polar coronal holes as they
appear on the... | physics |
6,348 | Intracluster Planetary Nebulae in the Hydra I cluster | astro-ph.SR | Using the Multislit Imaging Spectroscopy (MSIS) technique at the FORS2
spectrograph on VLT-UT1, we have identified 60 Intracluster Planetary Nebula
(ICPN) candidates associated with the Intracluster Light (ICL) in the central
region of the Hydra I cluster. Hydra I is a medium compact, relatively near
(~50 Mpc), rich cl... | physics |
6,349 | Simulations of magneto-hydrodynamic waves in atmospheres of roAp stars | astro-ph.SR | We report 2D time-dependent non-linear magneto-hydrodynamical simulations of
waves in the atmospheres of roAp stars. We explore a grid of simulations in a
wide parameter space. The aim of our study is to understand the influence of
the atmosphere and the magnetic field on the propagation and reflection
properties of ma... | physics |
6,350 | Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars | astro-ph.SR | We present interferometric angular sizes for 12 stars with known planetary
companions, for comparison with 28 additional main-sequence stars not known to
host planets. For all objects we estimate bolometric fluxes and reddenings
through spectral energy distribution fits, and in conjunction with the angular
sizes, measu... | physics |
6,351 | Low frequency QPO spectra and Lense-Thirring precession | astro-ph.SR | We show that the low frequency QPO seen in the power density spectra of black
hole binaries (and neutron stars) can be explained by Lense-Thirring
precession. This has been proposed many times in the past, and simple, single
radius models can qualitatively match the observed increase in QPO frequency by
decreasing a ch... | physics |
6,352 | The dust condensation sequence in red super-giant stars | astro-ph.SR | Context: Red super-giant (RSG) stars exhibit significant mass loss through a
slow and dense wind. They are often considered to be the more massive counter
parts of Asymptotic Giant Branch (AGB) stars. While the AGB mass loss is linked
to their strong pulsations, the RSG are often only weakly variable. Aim: To
study the... | physics |
6,353 | Keplerian frequency of uniformly rotating neutron stars and quark stars | astro-ph.SR | 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/10km)^-3/2, where M is the (gravitational) mass of Keplerian
configurati... | physics |
6,354 | Orbital eccentricity of binary radio pulsars in globular clusters and interaction between stars | astro-ph.SR | We analyze the observed distribution of the orbital eccentricity and period
of binary radio pulsars in globular clusters using computational tools to
simulate binary-single star interactions. Globular clusters have different
groups of pulsars arising from separate interaction scenarios. Intermediate
eccentricities of c... | physics |
6,355 | The chemical history of molecules in circumstellar disks. I. Ices | astro-ph.SR | (Abridged) Aims & Methods. A two-dimensional, semi-analytical model is
presented that follows, for the first time, the chemical evolution from a
collapsing molecular cloud (a pre-stellar core) to a protostar and
circumstellar disk. The model computes infall trajectories from any point in
the cloud and tracks the radial... | physics |
6,356 | V1647 Orionis: Reinvigorated Accretion and the Re-Appearance of McNeil's Nebula | astro-ph.SR | In late 2003, the young eruptive variable star V1647 Orionis optically
brightened by over 5 magnitudes, stayed bright for around 26 months, and then
decline to its pre-outburst level. In August 2008 the star was reported to have
unexpectedly brightened yet again and we herein present the first detailed
observations of ... | physics |
6,357 | Electron Temperatures of Planetary Nebulae Determined from the He I Discontinuities | astro-ph.SR | We have used the He I discontinuities at 3421A to determine the electron
temperatures, designated Te(He I), for a sample of five Galactic planetary
nebulae (PNe). We compared Te(He I) with the electron temperatures derived from
the hydrogen Balmer jump at 3646A, designated Te(H I), and found that Te(He I)
are generally... | physics |
6,358 | The Hydrodynamic Environment for the s Process in the He-Shell Flash of AGB Stars | astro-ph.SR | The He-shell flash convection in AGB stars is the site for the
high-temperature component of the s-process in low- and intermediate mass
giants, driven by the Ne22 neutron source. [...] The upper convection boundary
plays a critical role during the H-ingestion episode that may lead to
neutron-bursts in the most metal-p... | physics |
6,359 | Precision Astrometry with the Very Long Baseline Array: Parallaxes and Proper Motions for 14 Pulsars | astro-ph.SR | Astrometry can bring powerful constraints to bear on a variety of scientific
questions about neutron stars, including their origins, astrophysics,
evolution, and environments. Using phase-referenced observations at the VLBA,
in conjunction with pulsar gating and in-beam calibration, we have measured the
parallaxes and ... | physics |
6,360 | Pulsar glitch substructure and pulsar interiors | astro-ph.SR | Pulsar timing at the Mt Pleasant observatory focused on Vela, which could be
tracked for 18 hours of the day. These nearly continuous timing records extend
over 24 years allowing a great insight into details of timing noise, micro
glitches and other more exotic effects. It has been found that the spin up for
the Vela p... | physics |
6,361 | Dynamo-generated magnetic fields in fast rotating single giants | astro-ph.SR | Red giants offer a good opportunity to study the interplay of magnetic fields
and stellar evolution. Using the spectro-polarimeter NARVAL of the Telescope
Bernard Lyot (TBL), Pic du Midi, France and the LSD technique, we began a
survey of magnetic fields in single G-K-M giants. Early results include 6
MF-detections wit... | physics |
6,362 | Pulsars as Fantastic Objects and Probes | astro-ph.SR | Pulsars are fantastic objects, which show the extreme states of matters and
plasma physics not understood yet. Pulsars can be used as probes for the
detection of interstellar medium and even the gravitational waves. Here I
review the basic facts of pulsars which should attract students to choose
pulsar studies as their... | physics |
6,363 | Asteroseismology and evolution of EHB stars | astro-ph.SR | The properties of the Extreme Horizontal Branch stars are quite well
understood, but much uncertainty surrounds the many paths that bring a star to
this peculiar configuration. Asteroseismology of pulsating EHB stars has been
performed on a number of objects, bringing us to the stage where comparisons of
the inferred p... | physics |
6,364 | The Temperature and Density Structure of the Solar Corona. I. Observations of the Quiet Sun with the EUV Imaging Spectrometer (EIS) on Hinode | astro-ph.SR | Measurements of the temperature and density structure of the solar corona
provide critical constraints on theories of coronal heating. Unfortunately, the
complexity of the solar atmosphere, observational uncertainties, and the
limitations of current atomic calculations, particularly those for Fe, all
conspire to make t... | physics |
6,365 | Multiwavelength optical observations of two chromospherically active binary systems: V789 Mon and GZ Leo | astro-ph.SR | This paper describes a multiwavelengh optical study of chromospheres in two
X-ray/EUV selected active binary stars with strong H_alpha emission, V789 Mon
(2RE J0725-002) and GZ Leo (2RE J1101+223). The goal of the study is to
determine radial velocities and fundamental stellar parameters in
chromospherically active bin... | physics |
6,366 | Epicyclic oscillations of non-slender fluid tori around Kerr black holes | astro-ph.SR | Considering epicyclic oscillations of pressure-supported perfect fluid tori
orbiting Kerr black holes we examine non-geodesic (pressure) effects on the
epicyclic modes properties. Using a perturbation method we derive fully general
relativistic formulas for eigenfunctions and eigenfrequencies of the radial and
vertical... | physics |
6,367 | On the magnetic topology of partially and fully convective stars | astro-ph.SR | We compare the amount of magnetic flux measured in Stokes V and Stokes I in a
sample of early- and mid-M stars around the boundary to full convection
(~M3.5). Early-M stars possess a radiative core, mid-M stars are fully
convective. While Stokes V is sensitive to the net polarity of magnetic flux
arising mainly from la... | physics |
6,368 | MBM 12: young protoplanetary discs at high galactic latitude | astro-ph.SR | (abridged) We present Spitzer infrared observations to constrain disc and
dust evolution in young T Tauri stars in MBM 12, a star-forming cloud at high
latitude with an age of 2 Myr and a distance of 275 pc. The region contains 12
T Tauri systems, with primary spectral types between K3 and M6; 5 are weak-line
and the r... | physics |
6,369 | The Diskionary: A Glossary of Terms Commonly Used for Disks and Related Objects, First Edition | astro-ph.SR | Based on a panel discussion at the meeting "New Light on Young Stars:
Spitzer's View of Circumstellar Disks", we provide some definitions of common
usage of terms describing disks and related objects. | physics |
6,370 | Dust Formation Observed in Young Supernova Remnants with Spitzer | astro-ph.SR | We present dust features and masses observed in young supernova remnants
(SNRs) with Spitzer IRS mapping and staring observations of four youngest
supernova remnants: SNR 1E102.2-7219 (E0102) in the SMC, Cas A and G11.2-0.3 in
our Galaxy, and N132D in the LMC. The spectral mapping data revealed a number
of dust feature... | physics |
6,371 | Magnetic field observations of low-mass stars | astro-ph.SR | Direct measurements of magnetic fields in low-mass stars of spectral class M
have become available during the last years. This contribution summarizes the
data available on direct magnetic measurements in M dwarfs from Zeeman analysis
in integrated and polarized light. Strong magnetic fields at kilo-Gauss
strength are ... | physics |
6,372 | Analysis of the white--light flickering of the Intermediate Polar V709 Cas with wavelets and Hurst analysis | astro-ph.SR | We characterize the flickering observed in the optical lightcurve of the
Intermediate Polar system V709 Cas by determining its position in the
alpha-Sigma as in the Fritz and Bruch (1998) classification scheme. Sigma
represents the strength of flickering at a given timescale, while alpha
describes the energy distributi... | physics |
6,373 | Hot subdwarf binaries - Masses and nature of their heavy compact companions | astro-ph.SR | Neutron stars and stellar-mass black holes are the remnants of massive stars,
which ended their lives in supernova explosions. These exotic objects can only
be studied in relatively rare cases. If they are interacting with close
companions they become bright X-ray sources. If they are neutron stars, they
may be detecte... | physics |
6,374 | Nonlinear Fast Magnetoacoustic Wave Propagation in the Neighbourhood of a 2D magnetic X-point: Oscillatory Reconnection | astro-ph.SR | This paper extends the models of Craig & McClymont (1991) and McLaughlin &
Hood (2004) to include finite $\beta$ and nonlinear effects. We investigate the
nature of nonlinear fast magnetoacoustic waves about a 2D magnetic X-point. We
solve the compressible and resistive MHD equations using a Lagrangian remap,
shock cap... | physics |
6,375 | Modeling the Subsurface Evolution of Active Region Flux Tubes | astro-ph.SR | I present results from a set of 3D spherical-shell MHD simulations of the
buoyant rise of active region flux tubes in the solar interior which put new
constraints on the initial twist of the subsurface tubes in order for them to
emerge with tilt angles consistent with the observed Joy's law for the mean
tilt of solar a... | physics |
6,376 | The complex polarization angles of radio pulsars: orthogonal jumps and interstellar scattering | astro-ph.SR | Despite some success in explaining the observed polarisation angle swing of
radio pulsars within the geometric rotating vector model, many deviations from
the expected S-like swing are observed. In this paper we provide a simple and
credible explanation of these variations based on a combination of the rotating
vector ... | physics |
6,377 | On the formation of hot DQ white dwarfs | astro-ph.SR | We present the first full evolutionary calculations aimed at exploring the
origin of hot DQ white dwarfs. These calculations consistently cover the whole
evolution from the born-again stage to the white dwarf cooling track. Our
calculations provide strong support to the diffusive/convective-mixing picture
for the forma... | physics |
6,378 | The "Living with a Red Dwarf" Program | astro-ph.SR | Red Dwarfs (main-sequence / dwarf M or dM) stars are the most common stars in
the Galaxy. These cool, faint, low mass stars comprise over 75% of all stars.
Because of their low luminosities (~0.0008-0.06 of the Sun's luminosity), the
circumstellar habitable zones (HZs) of dM stars are located within ~0.05-0.4 AU
of the... | physics |
6,379 | Constraining white-dwarf kicks in globular clusters : IV. Retarding Core Collapse | astro-ph.SR | Observations of white dwarfs in the globular clusters NGC 6397 and
Omega Centauri indicate that these stars may get a velocity kick during their
time as giants. If the mass loss while on the asymptotic giant branch is
slightly asymmetric, the resulting white dwarf could be born with such a
velocity kick. These energe... | physics |
6,380 | Testing the models: NIR imaging and spectroscopy of the benchmark T-dwarf binary Eps Indi B | astro-ph.SR | The relative roles of metallicity and surface gravity on the near-infrared
spectra of late-T brown dwarfs are not yet fully understood, and evolutionary
models still need to be calibrated in order to provide accurate estimates of
brown dwarf physical parameters from measured spectra. The T-type brown dwarfs
Eps Indi Ba... | physics |
6,381 | Triggering Eruptive Mass Ejection in Luminous Blue Variables | astro-ph.SR | We study the runaway mass loss process of major eruptions of luminous blue
variables (LBVs) stars, such as the 1837-1856 Great Eruption of Eta Carinae. We
follow the evolution of a massive star with a spherical stellar evolution
numerical code. After the star exhausted most of the hydrogen in the core and
had developed... | physics |
6,382 | VLT/NACO coronagraphic observations of fine structures in the disk of beta Pictoris | astro-ph.SR | We present ground-based observations of the disk around the A-type star
$\beta$ Pictoris to perform a close inspection of the inner disk morphology.
Images were collected with NACO, the AO-assisted near-IR instrument on the VLT
(ESO) which includes two types of coronagraphs: classical Lyot masks and phase
masks. In thi... | physics |
6,383 | Discriminating between overshooting and rotational mixing in massive stars: any help from asteroseismology? | astro-ph.SR | Chemical turbulent mixing induced by rotation can affect the internal
distribution of mu near the energy-generating core of main-sequence stars,
having an effect on the evolutionary tracks similar to that of overshooting.
However, this mixing also leads to a smoother chemical composition profile near
the edge of the co... | physics |
6,384 | Post common envelope binaries from SDSS. IV: SDSSJ121258.25-012310.1, a new eclipsing system | astro-ph.SR | From optical photometry we show that SDSSJ121258.25-012310.1 is a new
eclipsing, post common-envelope binary with an orbital period of 8.06 hours and
an eclipse length of 23 minutes. We observed the object over 11 nights in
different bands and determined the ephemeris of the eclipse to HJD_mid =
2454104. 7086(2) + 0.33... | physics |
6,385 | Spitzer-IRAC GLIMPSE of high mass protostellar objects II - SED modelling of a bonafide sample | astro-ph.SR | We aim to estimate and analyse the physical properties of the infrared
counterparts of HMPOs by comparing their spectral energy distributions (SED)
with those predicted by radiative transfer accretion models of YSOs. The SED of
68 IRCs are extended beyond the GLIMPSE photometry to the possible limits, from
the near-inf... | physics |
6,386 | Testing the forward approach in modelling beta Cephei pulsators: setting the stage | astro-ph.SR | The information on stellar parameters and on the stellar interior we can get
by studying pulsating stars depends crucially on the available observational
constraints: both seismic constraints precision and number of detected modes,
identification, nature of the modes) and "classical" observations (photospheric
abundanc... | physics |
6,387 | A low energy core-collapse supernova without a hydrogen envelope | astro-ph.SR | The final fate of massive stars depends on many factors, including mass,
rotation rate, magnetic fields and metallicity. Theory suggests that some
massive stars (initially greater than 25-30 solar masses) end up as Wolf-Rayet
stars which are deficient in hydrogen because of mass loss through strong
stellar winds. The m... | physics |
6,388 | Turbulent diffusion with rotation or magnetic fields | astro-ph.SR | The turbulent diffusion tensor describing the evolution of the mean
concentration of a passive scalar is investigated for non-helically forced
turbulence in the presence of rotation or a magnetic field. With rotation, the
Coriolis force causes a sideways deflection of the flux of mean concentration.
Within the magnetoh... | physics |
6,389 | Driving Turbulence and Triggering Star Formation by Ionizing Radiation | astro-ph.SR | 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 with smoothed particle hydrodynamics (SPH) and
gravitational forces. We sh... | physics |
6,390 | X-ray and Radio Timing of the Pulsar in 3C 58 | astro-ph.SR | We present timing data spanning 6.4 yr for the young and energetic PSR
J0205+6449, in the supernova remnant 3C 58. Data were obtained with the Rossi
X-ray Timing Explorer, the Jodrell Bank Observatory and the Green Bank
Telescope. We present phase-coherent timing analyses showing timing noise and
two spin-up glitches w... | physics |
6,391 | Spectroscopic Detection of Carbon Monoxide in Two Late-type T Dwarfs | astro-ph.SR | M band spectra of two late-type T dwarfs, 2MASS J09373487+2931409, and Gliese
570D, confirm evidence from photometry that photospheric CO is present at
abundance levels far in excess of those predicted from chemical equilibrium.
These new and unambiguous detections of CO, together with an earlier
spectroscopic detectio... | physics |
6,392 | An Adaptive Optics Survey for Close Protostellar Binaries | astro-ph.SR | In order to test the hypothesis that Class I protostellar binary stars are a
product of ejections during the dynamical decay of non-hierarchical multiple
systems, we combined the results of new adaptive optics (AO) observations of
Class I protostars with our previously published AO data to investigate whether
Class I p... | physics |
6,393 | Carbon-rich RR Lyr type stars | astro-ph.SR | We have derived CNO abundances in 12 RR Lyrae stars. Four stars show [C/Fe]
near 0.0 and two stars show [C/Fe] = 0.52 and 0.65. Red giant branch stars,
which are known to be the predecessors of RR Lyrae stars, generally show a
deficiency of carbon due to proton captures during their evolution from the
main sequence up ... | physics |
6,394 | Raman Scattered HeII 6545 in the Young and Compact Planetary Nebula NGC 6790 | astro-ph.SR | We present the high resolution spectra of the youn and compact planerary
nebula NGC 6790 obtained with the echelle spectrograph at Bohyunsan Optical
Astronomy Observatory and report the discovery of Raman scattered He II 6545 in
this object. This line feature is formed in a thick neutral region surrounding
the hot cent... | physics |
6,395 | The CoRoT satellite in flight : description and performance | astro-ph.SR | CoRoT is a space telescope dedicated to stellar seismology and the search for
extrasolar planets. The mission is led by CNES in association with French
laboratories and has a large international participation: the European Space
Agency (ESA), Austria, Belgium and Germany contribute to the payload, and Spain
and Brazil ... | physics |
6,396 | Ultraviolet and extreme-ultraviolet line ratio diagnostics for O IV | astro-ph.SR | Aims: We generate theoretical ultraviolet and extreme-ultraviolet emission
line ratios for O IV and show their strong versatility as electron temperature
and density diagnostics for astrophysical plasmas. Methods: Recent fully
relativistic calculations of radiative rates and electron impact excitation
cross sections fo... | physics |
6,397 | The planetary nebula population of M33 and its metallicity gradient: A look into the galaxy's distant past | astro-ph.SR | 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 were performed on
the 93 PNe where the necessary diagnostic lines were measured. About 20% of the
PNe are comp... | physics |
6,398 | Carbon Monoxide in the Cassiopeia A Supernova Remnant | astro-ph.SR | We report the likely detection of near-infrared 2.29 $\mu$m first overtone
Carbon Monoxide (CO) emission from the young supernova remnant Cassiopeia A
(Cas A). The continuum-subtracted CO filter map reveals CO knots within the
ejecta-rich reverse shock. We compare the first overtone CO emission with that
found in the w... | physics |
6,399 | A Close Binary Star Resolved from Occultation by 87 Sylvia | astro-ph.SR | The star BD+29 1748 was resolved to be a close binary from its occultation by
the asteroid 87 Sylvia on 2006 December 18 UT. Four telescopes were used to
observe this event at two sites separated by some 80 km apart. Two flux drops
were observed at one site, whereas only one flux drop was detected at the
other. From th... | physics |
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