ISSN 1783-3426
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The variable stellar wind of Rigel
probed at high spatial and spectral resolution
Massive
open star clusters using the VVV survey III. A young massive cluster
at the far edge of the Galactic bar
The
Close Binary Frequency of Wolf-Rayet Stars as a Function of
Metallicity in M31 and M33
Modelling
of Sigma Scorpii, a high-mass binary with a Beta Cep variable primary
component
Masgomas-4: Physical
characterization of a double-core obscured cluster with a massive and
very young stellar population.
Discovery
of a Thorne-Żytkow object in the Small Magellanic Cloud
Discovery
of X-ray pulsations from a massive star
Investigation
of the stellar content in the western part of the Carina
nebula
Effect of rotational mixing
and metallicity on the hot star wind mass-loss rates
Mass
loss from inhomogeneous hot star winds III. An effective-opacity
formalism for line radiative transfer in accelerating, clumped
two-component media, and first results on theory and
diagnostics
X-rays from wind-blown
bubbles: an XMM-Newton detection of NGC 2359
Second
announcement: Magnetism and variability in O stars
International
Workshop on Wolf-Rayet Stars
Living
Together: Planets, Host Stars and Binaries
Thomas Rivinius
ESO
Dear
colleagues,
The Active B star community has suffered a sudden
and tragic loss when our friend and colleague Stanislav Stefl died in
a car accident Wednesday night, June 11 in Santiago de Chile.
The
working group has created a page in memory of Stan at:
http://activebstars.iag.usp.br/index.php/be-star-newsletter/volume-41/wg-matters-41/47-stan
Thomas Rivinius
Reference: N/A
Status:
Other
Weblink:
http://activebstars.iag.usp.br/index.php/be-star-newsletter/volume-41/wg-matters-41/47-stan
Comments:
Email: triviniu@eso.org
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O. Chesneau {1}, A. Kaufer {2}, O. Stahl {3}, C. Colvinter
{1}, A. Spang {1}, L. Dessart {4}, R. Prinja {5} and R. Chini
{6,7}
{1} Laboratoire Lagrange, UMR7293, Univ. Nice
Sophia-Antipolis, CNRS, Observatoire de la C^ote d'Azur, F-06300
Nice, France and
{2} European Southern Observatory, Alonso de
Cordova 3107, Casilla 19001, Santiago 763-0355, Chile
and {3}
ZAH, Landessternwarte, K"onigstuhl 12, D-69117 Heidelberg,
Germany and
{4} Laboratoire d'Astrophysique de Marseille, Universit'e de
Provence, CNRS, 38 rue Fr'ed'eric Joliot-Curie, F-13388 Marseille
Cedex 13, France and
{5} Department of Physics & Astronomy,
University College London, Gower Street, London, WC1E 6BT, UK and
{6} Instituto de Astronom'{i}a, Universidad Cat'{o}lica del
Norte, Avenida Angamos 0610, Antofagasta, Chile and
{7}
Astronomisches Institut, Ruhr-Universit"at Bochum,
Universit"atsstrass{}e 150, D-44801 Bochum, Germany
We
present a spatially resolved, high-spectral resolution (R=12000)
K-band temporal monitoring of Rigel using AMBER at the VLTI. Rigel
was observed in the Bracket Gamma line and its nearby continuum in
2006-2007, and 2009-2010. These unprecedented observations were
complemented by contemporaneous optical high-resolution spectroscopy.
We analyse the near-IR spectra and visibilities with the 1D non-LTE
radiative-transfer code CMFGEN. The differential and closure phase
signal exhibit asymmetries that are interpreted as perturbations of
the wind. A systematic visibility decrease is observed across the
Bracket Gamma. During the 2006-2007 period the Bracket Gamma and
likely the continuum forming regions were larger than in the
2009-2010 epoch. Using CMFGEN, we infer a mass-loss rate change of
about 20% between the two epochs. We further find time variations in
the differential visibilities and phases. The 2006-2007 period is
characterized by noticeable variations of the differential
visibilities in Doppler position and width and by weak variations in
differential and closure phase. The 2009-2010 period is much more
quiet with virtually no detectable variations in the dispersed
visibilities but a strong S-shape signal is observed in differential
phase coinciding with a strong ejection event discernible in the
optical spectra. The differential phase signal that is sometimes
detected is reminiscent of the signal computed from hydrodynamical
models of corotating interaction regions. For some epochs the
temporal evolution of the signal suggests the rotation of the
circumstellar structures.
Reference: Manuscript
accepted in the A&A Journal
Status: Manuscript has been
accepted
Weblink: http://arxiv.org/abs/1405.0907
Comments:
Email: Olivier.Chesneau@oca.eu
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S. Ramírez Alegría (1,2),
J. Borissova (1,2), A.N. Chené (3), E. O'Leary (3), P. Amigo (1,2),
D. Minniti (2,4), R. K. Saito (5), D. Geisler (6), R. Kurtev (1,2),
M. Hempel (2,4), M. Gromadzki (1), J. R. A. Clarke (1), I. Negueruela
(7), A. Marco (7), C. Fierro (1,8), C. Bonatto (9), M. Catelan
(2,4)
(1) Instituto de Física y Astronomía, Universidad
de Valparaíso, Chile; (2) The Millennium Institute of Astrophysics
(MAS), Chile; (3) Gemini North Observatory, USA; (4) Pontificia
Universidad Católica de Chile, Instituto de Astrofísica, Chile; (5)
Universidade Federal de Sergipe, Departamento de Física, Brazil; (6)
Departamento de Astronomía, Universidad de Concepción, Chile; (7)
Departamento de Física, Ingeniería de Sistemas y Teoría de la
Señal, Universidad de Alicante, Spain; (8) Escuela Superior de
Física y Matemáticas del Instituto Politécnico Nacional, México;
(9) Universidade Federal do Rio Grande do Sul, Departamento de
Astronomia, Brazil
We present the third article in a series of
papers focused on young and massive clusters discovered in the VVV
survey. This article is dedicated to the physical characterization of
VVV CL086, using part of its OB-stellar population.
We physically
characterized the cluster using JHKs near-infrared photometry from
ESO public survey VVV images, using the VVV-SkZ pipeline, and
near-infrared K-band spectroscopy, following the methodology
presented in the first article of the series.
Individual
distances for two observed stars indicate that the cluster is located
at the far edge of the Galactic bar. These stars, which are probable
cluster members from the statistically field-star decontaminated CMD,
have spectral types between O9 and B0 V. According to our analysis,
this young cluster (1.0 Myr < age < 5.0 Myr) is located at a
distance of 11 kpc, and we estimate a lower limit for the cluster
total mass of (2.8·10^3) solar masses. It is likely that the cluster
contains even earlier and more massive stars.
Reference:
Astronomy & Astrophysics, Volume 564, id.L9, 4 pp
Status:
Manuscript has been accepted
Weblink:
http://arxiv.org/abs/1403.3428
Comments:
Email: sebastian.ramirez@uv.cl
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Kathryn F. Neugent (1) and
Philip Massey (1)
(1) Lowell Observatory
Massive
star evolutionary models generally predict the correct ratio of
WC-type and WN-type Wolf-Rayet stars at low metallicities, but
underestimate the ratio at higher (solar and above) metallicities.
One possible explanation for this failure is perhaps single-star
models are not sufficient and Roche-lobe overflow in close binaries
is necessary to produce the "extra" WC stars at higher
metallicities. However, this would require the frequency of close
massive binaries to be metallicity dependent. Here we test this
hypothesis by searching for close Wolf-Rayet binaries in the high
metallicity environments of M31 and the center of M33 as well as in
the lower metallicity environments of the middle and outer regions of
M33. After identifying ~100 Wolf-Rayet binaries based on radial
velocity variations, we conclude that the close binary frequency of
Wolf-Rayets is not metallicity dependent and thus other factors must
be responsible for the overabundance of WC stars at high
metallicities. However, our initial identifications and observations
of these close binaries have already been put to good use as we are
currently observing additional epochs for eventual orbit and mass
determinations.
Reference: ApJ, in press
Status:
Manuscript has been accepted
Weblink:
http://arxiv.org/abs/1405.1810
Email:
phil.massey@lowell.edu
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A. Tkachenko (1), C. Aerts
(1,2), K. Pavlovski (3), P. Degroote (1), P. I. Papics (1), E.
Moravveji (1), H. Lehmann (4), V. Kolbas (3), and K. Clemer (1)
(1)
Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, B-3001
Leuven, Belgium; (2) Department of Astrophysics, IMAPP, Radboud
University Nijmegen, 6500 GL Nijmegen, The Netherlands; (3)
Department of Physics, University of Zagreb, Bijenicka cesta 32,
10000 Zagreb, Croatia; (4) Thueringer Landessternwarte Tautenburg,
07778 Tautenburg, Germany
High-mass binary stars are known to
show an unexplained discrepancy between the dynamical masses of the
individual components and those predicted by models. In this work, we
study Sigma Scorpii, a double-lined spectroscopic binary system
consisting of two B-type stars residing in an eccentric orbit. The
more massive primary component is a Beta Cep-type pulsating variable
star. Our analysis is based on a time-series of some 1000 high
resolution spectra collected with the CORALIE spectrograph in 2006,
2007, and 2008. We use two different approaches to determine the
orbital parameters of the star; the spectral disentangling technique
is used to separate the spectral contributions of the individual
components in the composite spectra. The non-LTE based spectrum
analysis of the disentangled spectra reveals two stars of similar
spectral type and atmospheric chemical composition. Combined with the
orbital inclination angle estimate found in the literature, our
orbital elements allow a mass estimate of 14.7 +/- 4.5 and 9.5 +/-
2.9 solar masses for the primary and secondary component,
respectively. The primary component is found to pulsate in three
independent modes, of which two are identified as fundamental and
second overtone radial modes, while the third is an l = 1 non-radial
mode. Seismic modelling of the pulsating component refines stellar
parameters to 13.5 +0.5/-1.4 and 8.7 +0.6/-1.2 solar masses , and
delivers radii of 8.95 +0.43/-0.66 and 3.90 +0.58/-0.36 solar radii
for the primary and secondary, respectively. The age of the system is
estimated to be ~12 Myr.
Reference: Monthly Notices of
the Royal Astronomical Society (MNRAS)
Status: Manuscript has been
accepted
Weblink: http://arxiv.org/abs/1405.0924
Comments:
Email: Andrew.Tkachenko@ster.kuleuven.be
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S. Ramírez Alegría (1,2),
A. Marín-Franch (3), & A. Herrero (4,5)
(1) The
Millennium Institute of Astrophysics (MAS), Santiago, Chile; (2)
Instituto de Astrofísica, Universidad de Valparaíso, Valparaíso,
Chile; (3) Centro de Estudios de Física del Cosmos de Aragón
(CEFCA), Teruel, Spain; (4) Instituto de Astrofísica de Canarias,
Tenerife, Spain; (5) Departamento de Astrofísica, Universidad de La
Laguna, Tenerife, Spain.
The discovery of new, obscured
massive star clusters has changed our understanding of the Milky Way
star-forming activity from a passive to a very active star-forming
machine. The search for these obscured clusters is strongly supported
by the use of all-sky, near-IR surveys.
The main goal of the
MASGOMAS project is to search for and study unknown, young, and
massive star clusters in the Milky Way, using near-IR data. Here we
try to determine the main physical parameters (distance, size, total
mass, and age) of Masgomas-4, a new double-core obscured cluster.
Using near-IR photometry (J, H, and Ks) we selected a total of 21
stars as OB-type star candidates. Multi-object, near-IR follow-up
spectroscopy allowed us to carry out the spectral classification of
the OB-type candidates.
Of the 21 spectroscopically observed
stars, ten are classified as OB-type stars, eight as F- to early
G-type dwarf stars, and three as late-type giant stars.
Spectroscopically estimated distances indicate that the OB-type stars
belong to the same cluster, located at a distance of 1.90 kpc. Our
spectrophotometric data confirm a very young and massive stellar
population, with a clear concentration of pre-main-sequence massive
candidates (Herbig Ae/Be) around one of the cluster cores. The
presence of a surrounding HII cloud and the Herbig Ae/Be candidates
indicate an upper age limit of 5 Myr.
Reference: A&A,
accepted (05/09/14 )
Status: Manuscript has been
accepted
Weblink: http://arxiv.org/abs/1405.4494
Email:
sebastian.ramirez@uv.cl
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Emily M. Levesque, Philip
Massey, Anna N. Żytkow, Nidia Morrell
University of
Colorado; Lowell Observatory; University of Cambridge; Carnegie
Observatories
Thorne-Żytkow objects (TŻOs) are a theoretical
class of star in which a compact neutron star is surrounded by a
large, diffuse envelope. Supergiant TŻOs are predicted to be almost
identical in appearance to red supergiants (RSGs). The best features
that can be used at present to distinguish TŻOs from the general RSG
population are the unusually strong heavy-element and Li lines
present in their spectra, products of the star's fully convective
envelope linking the photosphere with the extraordinarily hot burning
region in the vicinity of the neutron star core. Here we present our
discovery of a TŻO candidate in the Small Magellanic Cloud. It is
the first star to display the distinctive chemical profile of
anomalous element enhancements thought to be unique to TŻOs. The
positive detection of a TŻO will provide the first direct evidence
for a completely new model of stellar interiors, a theoretically
predicted fate for massive binary systems, and never-before-seen
nucleosynthesis processes that would offer a new channel for Li and
heavy-element production in our universe.
Reference: MNRAS
Letters, in press
Status: Manuscript has been accepted
Weblink:
http://arxiv.org/abs/1406.0001
Comments:
5 pages, 3 figures
Email:
Emily.Levesque@colorado.edu
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Lidia M. Oskinova (1), Yael
Naze (2),
Helge Todt (1) , David P. Huenemoerder (3),
Richard
Ignace (4), Swetlana Hubrig (5), Wolf-Rainer Hamann (1)
(1)
University of Potsdam, (2) University of Liege, (3) MIT, (4) ETSU,
(5) AIP
X-ray emission from stars much more massive than the
Sun was discovered only 35 years ago. Such stars drive fast stellar
winds where shocks can develop, and it is commonly assumed that the
X-rays emerge from the shock-heated plasma. Many massive stars
additionally pulsate. However, hitherto it was neither theoretically
predicted nor observed that these pulsations would affect their X-ray
emission. All X-ray pulsars known so far are associated with
degenerate objects, either neutron stars or white dwarfs. Here we
report the discovery of pulsating X-rays from a non-degenerate
object, the massive B-type star Xi1 CMa. This star is a variable of
beta Cep-type and has a strong magnetic field. Our observations with
the X-ray Multi-Mirror (XMM-Newton) telescope reveal X-ray pulsations
with the same period as the fundamental stellar oscillations. This
discovery challenges our understanding of stellar winds from massive
stars, their X-ray emission and their magnetism.
Reference:
Nature Communications 5, 4024
doi:10.1038/ncomms5024
Status:
Manuscript has been accepted
Weblink:
arXiv:1406.0845
Comments:
http://sci.esa.int/xmm-newton/54101-pulsating-x-rays-allow-xmm-newton-to-unmask-a-mysterious-star/
Email:
lida@astro.physik.uni-potsdam.de
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Brajesh Kumar, Saurabh
Sharma, Jean Manfroid, Eric Gosset, Gregor Rauw, Yael Naze, and Ram
Kesh Yadav
1,2,7 : Aryabhatta Research Institute of
1,3,4,5,6 : Observational Sciences (India), University of Liege
(Belgium)
We obtained deep $UBVRI$ H$alpha$ photometric data
of the field situated to the west of the main Carina nebula and
centered on WR~22. Medium-resolution optical spectroscopy of a
subsample of X-ray selected objects along with archival data sets
from $Chandra$, $XMM-Newton$ and 2MASS surveys were used for the
present study. Different sets of color-color and color-magnitude
diagrams are used to determine reddening for the region and to
identify young stellar objects (YSOs) and estimate their age and
mass. Our spectroscopic results indicate that the majority of the
X-ray sources are late spectral type stars.
The region shows a
large amount of differential reddening with minimum and maximum
values of $E(B-V)$ as 0.25 and 1.1 mag, respectively. Our analysis
reveals that the total-to-selective absorption ratio $R rm_{V}$ is
$sim$3.7 $pm$ 0.1, suggesting an abnormal grain size in the observed
region. We identified 467 YSOs and studied their characteristics. The
ages and masses of the 241 optically identified YSOs range from
$sim$0.1 to 10 Myr and $sim$0.3 to 4.8M$_odot$, respectively.
However, the majority of them are younger than 1 Myr and have masses
below 2 M$_odot$. The high mass star WR 22 does not seem to have
contributed to the formation of YSOs in the CrW region. The initial
mass function slope, $Gamma$, in this region is found to be -1.13
$pm$ 0.20 in the mass range of 0.5 < M/M$_odot$ < 4.8. The
$K$-band luminosity function slope ($alpha$) is also estimated as
0.31 $pm$ 0.01. We also performed minimum spanning tree analysis of
the YSOs in this region, which reveals that there are at least ten
YSO cores associated with the molecular cloud, and that leads to an
average core radius of 0.43 pc and a median branch length of 0.28
pc.
Reference: 23 pages, 19 figures, 4 tables, Accepted
for publication in Astronomy
& Astrophysics
Status:
Manuscript has been accepted
Weblink:
http://arxiv.org/abs/1406.0994
Email:
brajesharies@gmail.com
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Jiri Krticka, Jiri
Kubat
Masaryk University, Brno, Czech Republic
Astronomical Institute, Ondrejov, Czech Republic
Hot star
wind mass-loss rates depend on the abundance of individual elements.
This dependence is usually accounted for assuming scaled solar
chemical composition. However, this approach may not be justified in
evolved rotating stars. The rotational mixing brings CNO-processed
material to the stellar surface, increasing the abundance of nitrogen
at the expense of carbon and oxygen, which potentially influences the
mass-loss rates. We study the influence of the modified chemical
composition resulting from the rotational mixing on the wind
parameters, particularly the wind mass-loss rates. We use our NLTE
wind code to predict the wind structure and compare the calculated
wind mass-loss rate for the case of scaled solar chemical composition
and the composition affected by the CNO cycle. We show that for a
higher mass-fraction of heavier elements Z/Z⊙≳0.1 the change of
chemical composition from the scaled solar to the CNO-processed
scaled solar composition does not significantly affect the wind
mass-loss rates. The missing line force caused by carbon and oxygen
is compensated for by nitrogen line force. However, for a very
low-mass fraction of heavier elements Z/Z⊙≲0.1 the rotational
mixing significantly affects the wind mass-loss rates. Moreover, the
decrease of the mass-loss rate with metallicity is stronger at such
low metallicities. We study the relevance of the wind
momentum-luminosity relationship for different metallicities and show
that for a metallicity Z/Z⊙≲0.1 the relationship displays a large
scatter, which depreciates the use of this relationship at the lowest
metallicities.
Reference: Astronomy & Astrophysics,
in press
Status: Manuscript has been accepted
Weblink:
http://lanl.arxiv.org/abs/1406.1288
Email:
krticka@physics.muni.cz
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J.O. Sundqvist(1), J. Puls(1), S.P. Owocki(2)
1
- University of Munich; 2 - University of Delaware
Aim: To
provide a fast and easy-to-use formalism for treating the reduction
in effective opacity associated with optically thick clumps in an
accelerating two-component medium. Method: We develop and benchmark
effective-opacity laws for continuum and line radiative transfer that
bridge the limits of optically thin and thick clumps. We then use
this formalism to i) design a simple method for modeling and
analyzing UV wind resonance lines in hot, massive stars, and ii)
derive simple correction factors to the line force driving the
outflows of such stars. Results: Using a vorosity-modified Sobolev
with exact integration (vmSEI) method, we show that, for a given
ionization factor, UV resonance doublets may be used to analytically
predict the upward corrections in empirically inferred mass-loss
rates associated with porosity in velocity space (a.k.a.
velocity-porosity, or vorosity). However, we also show the presence
of a solution degeneracy: in a two-component clumped wind with given
inter-clump medium density, there are always two different solutions
producing the same synthetic doublet profile. We demonstrate this by
application to SiIV and PV in B and O supergiants and derive, for an
inter-clump density set to 1 % of the mean density, upward empirical
mass-loss corrections of typically factors of either ~5 or ~50,
depending on which of the two solutions is chosen. Overall, our
results indicate that this solution dichotomy severely limits the use
of UV resonance lines as direct mass-loss indicators in current
diagnostic models of clumped hot stellar winds. We next apply the
effective line-opacity formalism to the standard CAK theory of
line-driven winds. A simple vorosity correction factor to the CAK
line force is derived, which for normalized velocity filling factor
fvel simply scales as fvel^alpha, where alpha characterizes the slope
of the CAK line-strength distribution function. By analytic and
numerical hydrodynamics calculations, we further show that in cases
where vorosity is important at the critical point setting the
mass-loss rate, the reduced line force leads to a lower theoretical
mass loss, by simply a factor fvel. On the other hand, if vorosity is
important only above this critical point, the predicted mass loss is
not affected, but the wind terminal speed is reduced, by a factor
scaling as fvel^(alpha/(2-2alpha)). This shows that porosity in
velocity space can have a significant impact not only on the
diagnostics, but also on the dynamics and theory of radiatively
driven winds.
Reference: Accepted for publication in
Astronomy and Astrophysics. Pre-print available at ArXiv.
Status:
Manuscript has been accepted
Weblink:
http://arxiv.org/abs/1405.7800
Comments:
Email: mail@jonsundqvist.com
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Svetozar A. Zhekov
Space
Research and Technology Institute, Sofia, Bulgaria
We present
an analysis of the XMM-Newton observation of the
wind-blown
bubble NGC 2359. This is the first detection of this object
in
X-rays. The X-ray emission of NGC 2359 is soft and originates from
a
thermal plasma with a typical temperature of kT ~ 0.2 keV. A direct
comparison between the one-dimensional hydrodynamic model of
wind-blown bubbles and the X-ray spectrum of NGC 2359 suggests a
reduced mass-loss rate of the central star in order to provide
the
correct value of the observed flux. The central star of the
nebula,
WR 7, is an X-ray source. Its emission is similar to that
of other
presumably single Wolf-Rayet stars detected in X-rays.
The WR 7
spectrum is well represented by the emission from a
two-temperature
plasma with a cool component of kT ~ 0.6 keV and
a hot component of kT
~ 2.7 keV.
Reference: Monthly
Notices of the Royal Astronomical Society
Status: Manuscript has
been accepted
Weblink:
http://arxiv.org/abs/1406.2463
Comments:
Email: szhekov@space.bas.bg
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17-19 September 2014
Venue:
De Rode Hoed, Amsterdam, The Netherlands
Variability is a
fundamental property of OB star winds. This variability is not
strictly periodic, but cyclic on a timescale that scales with the
estimated rotation period of the star. The underlying cause or
trigger of this variability is not known.The major time-variable wind
features likely find their origin close to, or at the surface of the
star, and have been suggested to be connected to non-radial
pulsations or bright magnetic star spots.
The past few years
have shown very promising new developments, both observationally and
theoretically. High-precision space-based photometry reveals rapid
variations, incompatible with pulsations, but consistent with the
continuous presence of co-rotating bright stellar spots. These spots
could be of magnetic origin; surface magnetic fields have recently
been detected in several OB-type stars, and theoretical studies show
that magnetic fields can be generated in massive stars.
Understanding the role of magnetic fields and variability in
O and early B stars, in the context of their internal structure,
stellar winds, and evolution, is a major challenge in massive star
research. This is the focus of a 3-day conference to be held in
Amsterdam, organized to mark the formal retirement of Huib Henrichs,
one of the pioneers of this field of research.
Important
dates:
----------------
May 15th: Second announcement and
registration
June 1st: Deadline abstract submission
June
16th: Deadline block-booking hotels
July 1st: Deadline early
payment registration fee
August 1st: Registration closed
Registration:
-------------
Please register for
participation at your earliest convenience. In case you would like to
give an oral presentation, please submit your abstract before June
1st, 2014. Payment of the registration fee can be done electronically
through our website. The registration fee is 275 Euro when paid
before July 1st, 2014, the fee includes coffee/tea, lunches and the
conference dinner; the late registration fee is 325 Euro. The
registration will close on August 1st, 2014.
Scientific
programme:
---------------------
We aim for 50-100
participants; rather than having a skeleton program with invited
speakers, the community is invited to come forward on their own
accord, and the SOC will construct a scientific programme from the
input received. So far, over 40 participants have registered and
provided a title for a talk or a poster; the current list already
promises a very exciting scientific programme. In order to construct
the preliminary programme, the participants are requested to submit
an abstract (deadline June 1st, 2014) to the SOC (L.Kaper@uva.nl).
Social programme:
-----------------
-Tuesday
September 16:
Public lecture by Huib Henrichs
Welcome
reception at Science Park
-Wednesday Sep 17 – Friday Sep 19:
Conference at De Rode Hoed
-Thursday September 18:
Conference dinner
-Saturday September 20:
Social outing
Accommodation:
--------------
Amsterdam is a
touristic place, so it is recommended to make hotel reservations at
your earliest convenience. We have made block bookings at some hotels
near the city center (De Rode Hoed is in the city center); the
deadline for these block booking (and discount) is June 16th, 2014.
Amsterdam Schiphol airport is well connected to the city center by
public transport.
Weblink:
http://www.astro.uva.nl/ostars/
Email:
ostarsws@list.uva.nl
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1. - 5. June 2015
Venue:
Potsdam (Germany)
This workshop is the first conference in
a long time that is specifically dedicated to Wolf-Rayet stars.
Considerable progress has been made meanwhile in modeling and
analyzing their spectra, understanding their evolutionary context,
and quantifying their feedback. Nevertheless, major questions remain
heavily debated. This workshop shall bring together the experts in
the field to discuss its recent progress, open issues, and future
perspectives. The meeting should also motivate young scientists for
joining the research on Wolf-Rayet stars with their broad
astrophysical context.
Weblink:
http://www.astro.physik.uni-potsdam.de/~wr2015/
Email:
wr2015@astro.physik.uni-potsdam.de
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September 8-12, 2014
Venue: Litomyšl,
Czech Republic
In celebration of the 100th anniversary of
prof. Zdeněk Kopal birth, we are organizing a conference in his
hometown with following topics:
•Evolution of angular momentum:
Formation of binary stars and of planetary systems.
•Detection
of planetary systems. New techniques and new results.
•Results
from the space missions for binary stars and exo-planets.
•Evolution
of planetary systems. Stability of planetary systems and planetary
migrations.
•Internal structure of planets. Planetary
atmospheres.
•Planetary systems in binary stars.
•Unsolved
problems in structure and evolution of binary stars.
•Directions
for further research in binary stars and exo-planets.
•Zdeněk
Kopal and his legacy.
Weblink:
http://astro.physics.muni.cz/kopal2014
Email:
zejda@physics.muni.cz
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