ISSN 1783-3426
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Luminous and Variable Stars in M31 and
M33. IV. Luminous Blue Variables, Candidates LBVs, B[e] Supergiants,
and the Warm Hypergiants; How to Tell Them Apart
A
Modern Search for Wolf-Rayet Stars in the Magellanic Clouds. III. A
Third Year of Discoveries
The
detection of variable radio emission from the fast rotating magnetic
hot B-star HR7355 and evidence for its X-ray aurorae
How
unique is Plaskett's star? A search for organized magnetic fields in
short period, interacting or post-interaction massive binary
systems
The VLT-FLAMES Tarantula
Survey XXVI: Properties of the O-dwarf population in 30 Doradus
Monitoring Luminous Yellow Massive Stars in M33: New Yellow Hypergiant Candidates
Perspectives for observing hot massive
stars with XMM-Newton in the years 2017 -- 2027
The
Red Supergiant Content of the Local Group
The
evolution of magnetic hot massive stars: Implementation of the
quantitative influence of surface magnetic fields in modern models of
stellar evolution
Recent advances
in non-LTE stellar atmosphere models
Winds from
massive stars: What are the real rates?
The
physics of evolved stars II: the role of binarity
Eta
Carinae, LBVs, and Supernova Impostors
Recent executive order by
the President of the United States suspended entry of all refugees to
the United States for 120 days, and blocked entry to the U.S. for at
least 90 days for citizens of seven countries. IAU is intrinsically
an international organization comprising of citizens from every
corner of the globe regardless of their national origin, religious
beliefs or sexual orientations. Thus, such a ban impacts our
activities directly and goes counter to our core beliefs. The
organizing committee of the IAU massive stars commission discussed
the situation. The IAU supports the International Council for Science
(ICSU) rules on Freedom, Responsibility and Universality of Science,
that include the freedom of movement. To deny participation in a
meeting because of nationality, political or religious beliefs are in
breach of the ICSU Principle of the Universality of Science, and all
member states are expected to abide by this principle.
For
this reason, the organizing committee of the IAU massive stars
commission believes the IAU should temporarily suspend all IAU
sponsored meetings in the USA and, if the order remains in effect in
the future, cancel them all. Moreover, we think that new IAU
sponsored meetings should not be approved while the order is in
effect. Although holding other non-IAU sponsored astronomical
meetings are left to individual organizing committees, we urge
everyone to uphold the principle of Universality of Science. If it is
at stake, consider appropriate actions, including the cancellation of
the meeting.
The Organizing Committee of the IAU Massive
Stars Commission
Artemio Herrero (president), Jorick Vink
(vice-president), Nicole St.-Louis (Secretary), You-Hua Chu, Jose
Groh, Gregor Rauw, Asif ud-Doula
Weblink:
Email:
ahd@iac.es
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Roberta M. Humphreys (1), Michael S. Gordon (1), John C.
Martin (2), Kerstin Weis (3),
and David Hahn(1)
1.
University of Minnesota, 2. University of Illinois Springfield, 3.
Astronomical Institute, Ruhr-Universitaet Bochum, Germany
In
this series of papers we have presented the results of a
spectroscopic survey of luminous stars in the nearby spirals M31 and
M33. Here, we present spectroscopy of 132 additional stars. Most have
emission line spectra, including LBVs and candidate LBVs, Fe II
emission line stars, the B[e] supergiants, and the warm hypergiants.
Many of these objects are spectroscopically similar and are often
confused with each other. We examine their similarities and
differences and propose the following guidelines to help distinguish
these stars in future work: 1. The B[e] supergiants have emission
lines of [O I] and [Fe II] in their spectra. Most of the
spectroscopically confirmed sgB[e] stars also have warm circumstellar
dust in their SEDs.2 Confirmed LBVs it do not have the [O I] emission
lines in their spectra. Some LBVs have [Fe II] emission lines, but
not all. Their SEDs shows free-free emission in the near infrared but
no evidence for warm dust. Their most important and defining
characteristic is the S Dor-type variability. 3. The warm hypergiants
spectroscopically resemble the LBVs in their dense wind state and the
B[e] supergiants. However, they are very dusty. Some have [Fe II] and
[O I] emission in their spectra like the sgB[e] stars, but are
distinguished by their A and F-type spectra. In contrast, the B[e]
supergiant spectra have strong continua and few if any apparent
absorption lines. Candidate LBVs should share the spectral
characteristics of the confirmed LBVs with low outflow velocities and
the lack of warm circumstellar dust.
Reference: To
appear in the Astrophysical Journal
Status: Manuscript has been
accepted
Weblink:
http://adsabs.harvard.edu/abs/2016arXiv161107986H
Comments:
Email: roberta@umn.edu
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Philip Massey (1), Kathryn F. Neugent (1), and Nidia
Morrell (2)
(1) Lowell Observatory, and Dept of
Physics & Astronomy, Northern Arizona University, (2) Las
Campanas Observatory, Carnegie Observatory
For the past
three years we have been conducting a survey for WR stars in the
Large and Small Magellanic Clouds (LMC, SMC). Our previous work has
resulted in the discovery of a new type of WR star in the LMC, which
we are calling WN3/O3. These stars have the emission-line properties
of a WN3 star (strong N V but no N IV), plus the absorption-line
properties of an O3 star (Balmer hydrogen plus Pickering He II, but
no He I). Yet these stars are 15× fainter than an O3 V star would be
by itself, ruling out these being WN3+O3 binaries. Here we report the
discovery of two more members of this class, bringing the total
number of these objects to 10, 6.5% of the LMC’s total WR
population. The optical spectra of nine of these WN3/O3s are
virtually indistinguishable from each other, but one of the newly
found stars is significantly different, showing a lower excitation
emission and absorption spectrum (WN4/O4-ish). In addition, we have
newly classified three unusual Of-type stars, including one with a
strong C III λ4650 line, and two rapidly rotating “Oef” stars.
We also “rediscovered” a low mass x-ray binary, RX J0513.9-6951,
and demonstrate its spectral variability. Finally, we discuss the
spectra of ten low priority WR candidates that turned out not to have
He II emission. These include both a Be star and a B[e]
star.
Reference: ApJ, in press
Status:
Manuscript has been accepted
Weblink:
https://arxiv.org/pdf/1701.07815v1.pdf
Comments:
Email: phil.massey@lowell.edu
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P. Leto, C. Trigilio, L. Oskinova, R. Ignace, C.S. Buemi,
G. Umana, A. Ingallinera, H. Todt, F. Leone
INAF -
Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123 Catania,
Italy
In this paper we investigate the multiwavelengths
properties of the magnetic early B-type star HR7355. We present its
radio light curves at several frequencies, taken with the Jansky Very
Large Array, and X-ray spectra, taken with the XMM X-ray telescope.
Modeling of the radio light curves for the Stokes I and V provides a
quantitative analysis of the HR7355 magnetosphere. A comparison
between HR7355 and a similar analysis for the Ap star CUVir, allows
us to study how the different physical parameters of the two stars
affect the structure of the respective magnetospheres where the
non-thermal electrons originate. Our model includes a cold thermal
plasma component that accumulates at high magnetic latitudes that
influences the radio regime, but does not give rise to X-ray
emission. Instead, the thermal X-ray emission arises from shocks
generated by wind stream collisions close to the magnetic equatorial
plane. The analysis of the X-ray spectrum of HR7355 also suggests the
presence of a non-thermal radiation. Comparison between the spectral
index of the power-law X-ray energy distribution with the non-thermal
electron energy distribution indicates that the non-thermal X-ray
component could be the auroral signature of the non-thermal electrons
that impact the stellar surface, the same non-thermal electrons that
are responsible for the observed radio emission. On the basis of our
analysis, we suggest a novel model that simultaneously explains the
X-ray and the radio features of HR7355 and is likely relevant for
magnetospheres of other magnetic early type stars.
Reference:
Leto et al., 2017, eprint arXiv:1701.07679
Status:
Manuscript has been accepted
Weblink:
https://arxiv.org/abs/1701.07679
Comments:
Email: paolo.leto@oact.inaf.it
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Y. Naze (ULg), C. Neiner (ObsPM), J. Grunhut (ESO,
Toronto Univ), S. Bagnulo (Armagh Obs), E. Alecian (IPAG, CNRS), G.
Rauw (ULg), G.A. Wade (RMC), the BinaMIcS collaboration
1-(ULg),
2- (ObsPM), 3 - (ESO, Toronto Univ), 4- (Armagh Obs), 5- (IPAG,
CNRS), 6- (ULg), 7- (RMC)
Amongst O-type stars with
detected magnetic fields, the fast rotator in the close binary called
Plaskett's star shows a variety of unusual properties. Since strong
binary interactions are believed to have occurred in this system, one
may wonder about their potential role in generating magnetic fields.
Stokes V spectra collected with the low-resolution FORS2 and
high-resolution ESPaDOnS and Narval spectropolarimeters were
therefore used to search for magnetic fields in 15 interacting or
post-interaction massive binaries. No magnetic field was detected in
any of them, with 0G always being within 2sigma of the derived
values. For 17 out of 25 stars in the systems observed at
high-resolution, the 90% upper limit on the individual dipolar fields
is below the dipolar field strength of Plaskett's secondary; a
similar result is found for five out of six systems observed at low
resolution. If our sample is considered to form a group of stars
sharing similar magnetic properties, a global statistical analysis
results in a stringent upper limit of ~200G on the dipolar field
strength. Moreover, the magnetic incidence rate in the full sample of
interacting or post-interaction systems (our targets + Plaskett's
star) is compatible with that measured from large surveys, showing
that they are not significantly different from the general O-star
population. These results suggest that binary interactions play no
systematic role in the magnetism of such massive systems.
Reference:
MNRAS, in press
Status: Manuscript has been
accepted
Weblink:
https://arxiv.org/abs/1701.05370
Comments:
Email: naze@astro.ulg.ac.be
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C. Sabín-Sanjulián(1,2), S.
Simón-Díaz(3,4), A. Herrero(3,4), J. Puls(5), F. R. N.
Schneider(6), C. J. Evans(7), M. Garcia(8), F. Najarro(8), I.
Brott(9), N. Castro(10), P. A. Crowther(11), A. de Koter(12,13), S.
E. de Mink(12), G. Gräfener(14), N. J. Grin(14), G. Holgado(3,4), N.
Langer(14), D. J. Lennon(15), J. Maíz Apellániz(16), O. H.
Ramírez-Agudelo(7), H. Sana(13), W. D. Taylor(7), J. S. Vink(17), N.
R. Walborn(18)
1.- Departamento de Física y
Astronomía, Universidad de La Serena, Av. Cisternas 1200 Norte, La
Serena, Chile
2.- Instituto de Investigación Multidisciplinar
en Ciencia y Tecnología, Universidad de La Serena, Raúl Bitrán
1305, La Serena, Chile
3.- Instituto de Astrofísica de
Canarias, E-38200 La Laguna, Tenerife, Spain
4.- Departamento
de Astrofísica, Universidad de La Laguna, E-38205 La Laguna,
Tenerife, Spain
5.- LMU Munich, Universitätssternwarte,
Scheinerstrasse 1, 81679 Munchen, Germany
6.- Department of
Physics, University of Oxford, Denys Wilkinson Building, Keble Road,
Oxford OX1 3RH, United Kingdom
7.- UK Astronomy Technology
Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK
8.- Centro de Astrobiolog ́ıa (CSIC-INTA), Ctra. de Torrejón
a Ajalvir km-4, E-28 850 Torrejón de Ardoz, Madrid, Spain
9.-
University of Vienna, Department of Astronomy, Türkenschanzstr. 17,
1180, Vienna, Austria
10.- Department of Astronomy, University
of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109-1107, USA
11.- Department of Physics & Astronomy, Hounsfield Road,
University of Sheffield, S3 7RH, UK
12.- Astronomical Institute
Anton Pannekoek, Amsterdam University, Science Park 904, 1098 XH,
Amsterdam, The Netherlands
13.- Instituut voor Sterrenkunde,
Universiteit Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium
14.- Argelander-Institut für Astronomie der Universit ̈at
Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
15.- European
Space Astronomy Centre (ESAC), Camino bajo del castillo, s/n
Urbanización Villafranca del Castillo, Villanueva de la Cañada,
E-28 692 Madrid, Spain
16.- Centro de Astrobiología,
CSIC-INTA, Campus ESAC, Camino bajo del castillo s/n, E-28 692
Madrid, Spain
17.- Armagh Observatory, College Hill, Armagh,
BT61 9DG, Northern Ireland, UK
18.- Space Telescope Science
Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
The
VLT-FLAMES Tarantula Survey has observed hundreds of O-type stars in
the 30 Doradus region of the Large Magellanic Cloud (LMC). We study
the properties of 105 apparently single O-type dwarfs. To determine
stellar and wind parameters, we used the IACOB-GBAT package, an
automatic procedure based on a large grid of atmospheric models
calculated with the FASTWIND code. In addition to classical
techniques, we applied the Bayesian BONNSAI tool to estimate
evolutionary masses. We provide a new calibration of effective
temperature vs. spectral type for O-type dwarfs in the LMC, based on
our homogeneous analysis of the largest sample of such objects to
date and including all spectral subtypes. Good agreement with
previous results is found, although the sampling at the earliest
subtypes could be improved. Rotation rates and helium abundances are
studied in an evolutionary context. We find that most of the rapid
rotators (vsini higher than 300 km/s ) in our sample have masses
below 25 MSun and intermediate rotation-corrected gravities (log gc
between 3.9 and 4.1). Such rapid rotators are scarce at higher
gravities (i.e. younger ages) and absent at lower gravities (larger
ages). This is not expected from theoretical evolutionary models,
and does not appear to be due to a selection bias in our sample. We
compare the estimated evolutionary and spectroscopic masses, finding
a trend that the former is higher for masses below 20 MSun. This can
be explained as a consequence of limiting our sample to the O-type
stars, and we see no compelling evidence for a systematic mass
discrepancy. For most of the stars in the sample we were unable to
estimate the wind-strength parameter (hence mass-loss rates)
reliably, particularly for objects with luminosity lower than
logL/LSun about 5.1. Ultraviolet spectroscopy is needed to undertake
a detailed investigation of the wind properties of these
dwarfs.
Reference: arXiv:1702.04773
Status:
Manuscript has been accepted
Weblink:
https://arxiv.org/abs/1702.04773
Comments:
Email: cssj@dfuls.cl
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M. Kourniotis (1,2), A.Z.
Bonanos (1), W. Yuan (3), L.M. Macri (3), D. Garcia-Alvarez (4,5,6),
and C.-H. Lee (7)
1-IAASARS, National Observatory of
Athens, GR-15236 Penteli, Greece
2-Section of Astrophysics,
Astronomy and Mechanics, Faculty of Physics, National and
Kapodistrian University of Athens, Panepistimiopolis, GR15784
Zografos, Athens, Greece
3-Mitchell Institute for Fundamental
Physics & Astronomy, Department of Physics & Astronomy, Texas
A&M University, College Station, TX 77843, USA
4-Dpto. de
Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife,
Spain
5-Grantecan CALP, 38712 Breña Baja, La Palma, Spain
6-Instituto de Astrofisica de Canarias, E-38205 La Laguna,
Tenerife, Spain
7-Subaru Telescope, National Astronomical
Observatory of Japan, 650 North Aohoku Place, Hilo, HI 96720,
USA
The evolution of massive stars surviving the red
supergiant (RSG) stage remains unexplored due to the rarity of such
objects. The yellow hypergiants (YHGs) appear to be the warm
counterparts of post-RSG classes located near the Humphreys-Davidson
upper luminosity limit, which are characterized by atmospheric
instability and high mass-loss rates. We aim to increase the number
of YHGs in M33 and thus to contribute to a better understanding of
the pre-supernova evolution of massive stars. Optical spectroscopy of
five dust-enshrouded YSGs selected from mid-IR criteria was obtained,
with the goal of detecting evidence of extensive atmospheres. We also
analyzed BVI photometry for 21 of the most luminous YSGs in M33 to
identify changes in the spectral type. To explore the properties of
circumstellar dust, we performed SED-fitting of multi-band photometry
of the 21 YSGs. We find three luminous YSGs in our sample to be YHG
candidates, as they are surrounded by hot dust and are enshrouded
within extended, cold dusty envelopes. Our spectroscopy of Star 2
shows emission of more than one H$\alpha$ components, as well as
emission of Ca II, implying expanding structures associated with
large outflow velocities. In addition, the long-term monitoring of
the star reveals a dimming in the visual light curve of amplitude
larger than 0.5 mag, which caused an apparent drop in the temperature
that exceeded 500 K. We suggest the observed variability to be
analogous to that of the Galactic YHG $\rho$ Cas. Five less luminous
YSGs are suggested as post-RSG candidates showing evidence of hot
or/and cool dust emission. We demonstrate that mid-IR photometry,
combined with optical spectroscopy and time-series photometry,
provide a robust method for identifying candidate YHGs. Future
discovery of YHGs in Local Group galaxies is critical for the study
of the late evolution of intermediate-mass massive stars.
Reference:
A&A
Status: Manuscript has been submitted
Weblink:
https://arxiv.org/abs/1612.06853
Comments:
Manuscript revised following the comments by the referee
Email:
mkourniotis@astro.noa.gr
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Gregor Rauw
Liege University,
Belgium
XMM-Newton has deeply changed our picture of X-ray
emission of hot, massive stars. High-resolution X-ray spectroscopy as
well as monitoring of these objects helped us gain a deeper insight
into the physics of single massive stars with or without magnetic
fields, as well as of massive binary systems, where the stellar winds
of both stars interact. These observations also revealed a number of
previously unexpected features that challenge our understanding of
the dynamics of the stellar winds of massive stars. I briefly
summarize the results obtained over the past 15 years and highlight
the perspectives for the next decade. It is anticipated that
coordinated (X-ray and optical or UV) monitoring and time-critical
observations of either single or binary massive stars will become the
most important topics in this field over the coming years. Synergies
with existing or forthcoming X-ray observatories (NuSTAR, Swift,
eROSITA) will also play a major role and will further enhance the
importance of XMM-Newton in our quest for understanding the physics
of hot, massive stars.
Reference: To appear in a
special issue of Astronomical Notes. Proceedings of the workshop
"XMM-Newton: The Next Decade", (ESAC, Villafranca del
Castillo, Spain, 9-11 May 2016)
Status: Conference
proceedings
Weblink: arXiv:1701.04557
Comments:
Email: rauw@astro.ulg.ac.be
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Phil Massey (1,), Emily Levesque (2), Kathryn Neugent
(1), Kate Evans (1,3), Maria Drout (4), Madeleine Beck (5)
(1)
Lowell Observatory; (2) Dept of Physics and Astronomy, Northern
Arizona University, (3) Caltech, (4) Observatories of the Carnegie
Institution for Science, (5) Wellesley Collage
We
summarize here recent work in identifying and characterizing red
supergiants (RSGs) in the galaxies of the Local Group.
Reference:
To appear in The Lives and Death-throes of Massive Stars,
Proceedings IAU Symposium No. 329.
Status: Conference
proceedings
Weblink:
http://arxiv.org/abs/1702.00221
Comments:
Email: phil.massey@lowell.edu
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Zsolt Keszthelyi [1,2], Gregg A. Wade [1], Veronique
Petit [3,4]
[1] Royal Military College of Canada
[2]
Queen's University
[3] Florida Institute of Technology
[4]
University of Delaware
Large-scale dipolar surface
magnetic fields have been detected in a fraction of OB stars, however
only few stellar evolution models of massive stars have considered
the impact of these fossil fields. We are performing 1D
hydrodynamical model calculations taking into account evolutionary
consequences of the magnetospheric-wind interactions in a simplified
parametric way. Two effects are considered: i) the global mass-loss
rates are reduced due to mass-loss quenching, and ii) the surface
angular momentum loss is enhanced due to magnetic braking. As a
result of the magnetic mass-loss quenching, the mass of magnetic
massive stars remains close to their initial masses. Thus magnetic
massive stars - even at Galactic metallicity - have the potential to
be progenitors of `heavy' stellar mass black holes. Similarly, at
Galactic metallicity, the formation of pair instability supernovae is
plausible with a magnetic progenitor.
Reference: to
appear in Proceedings of IAUS 329
Status: Conference
proceedings
Weblink:
https://arxiv.org/abs/1702.04460
Comments:
Email: zsolt.keszthelyi@rmc.ca
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Andreas A.C. Sander
Institut
fuer Physik & Astronomie, Universitaet Potsdam, Germany
In
the last decades, stellar atmosphere models have become a key tool in
understanding massive stars. Applied for spectroscopic analysis,
these models provide quantitative information on stellar wind
properties as well as fundamental stellar parameters. The intricate
non-LTE conditions in stellar winds dictate the development of
adequate sophisticated model atmosphere codes. The increase in both,
the computational power and our understanding of physical processes
in stellar atmospheres, led to an increasing complexity in the
models. As a result, codes emerged that can tackle a wide range of
stellar and wind parameters.
After a brief address of the
fundamentals of stellar atmosphere modeling, the current stage of
clumped and line-blanketed model atmospheres will be discussed.
Finally, the path for the next generation of stellar atmosphere
models will be outlined. Apart from discussing multidimensional
approaches, I will emphasize on the coupling of hydrodynamics with a
sophisticated treatment of the radiative transfer. This next
generation of models will be able to predict wind parameters from
first principles, which could open new doors for our understanding of
the various facets of massive star physics, evolution, and
death.
Reference: to be published in the
Proceedings of the IAU Symposium No. 329 "The lives and
death-throes of massive stars"
Status: Conference
proceedings
Weblink:
https://arxiv.org/abs/1702.04798
Comments:
8 pages, 1 figure
Email:
ansander@astro.physik.uni-potsdam.de
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28 June 2017
Venue: Faculty of Law
of the Charles University, Prague, Czech Republic
Massive
stars are among the key players that shape our Universe. The massive
stars are truly cosmic engines, which power the evolution of matter
in the Universe since the formation of first stars. The input of
massive star winds into the interstellar matter is mostly given by
two parameters: the wind mass-loss rate and the terminal velocity.
While the terminal velocity can be directly measured with high
precision, the mass-loss rates are strongly debated.
There
are several observational tracers of the mass-loss rate across the
whole electromagnetic spectrum. In the X-ray domain, the shape of the
emission line profiles is affected by the wind density and may
therefore be used to determine the wind mass-loss rate. Also the
strength of the ultraviolet P Cygni lines depends on the mass-loss
rate. The optical region can be reached from the ground, consequently
the H alpha emission line is most typically used mass-loss rate
indicator. The strength of the infrared recombination lines and radio
excess is also closely related to the wind mass-loss rate.
Ideally,
all these tracers should give the same mass-loss rate for the same
star, which should also agree with theoretical predictions. However,
this is not the case for many stars. The differences may amount to
one order of magnitude. This is a serious problem for stellar
evolutionary models and for the determination of the massive star
feedback because even a factor of two difference in the mass-loss
rates can have a drastic effect for the predicted (and actual)
evolution of massive stars. The differences between the individual
discordant determinations may be most likely attributed to the
influence of the small scale wind inhomogeneities (clumping) on the
diagnostics and on the predictions.
The aim of this
special session is to bring together experts on the observational and
theoretical studies of the massive star winds to establish the
current status of the field of the mass-loss rate determination,
discuss the critical uncertainties that are mostly connected with
wind inhomogeneities, and propose the best strategies to provide more
reliable mass-loss rate determinations to the astrophysical
community.
Programme
- Prediction of hot star wind
mass-loss rates from theory
- Observational hot star wind
mass-loss rates estimation: from X-rays to radio
- Influence of
inhomogeneities on the observational mass-loss rate indicators
-
Indirect mass-loss rate estimations
Invited speakers
-
Ronny Blomme (Royal Observatory of Belgium, Belgium)
- Maurice
Leutenegger (NASA/GSFC, USA)
- Francisco Najarro (Centro de
Astrobiología, Spain)
- Jon Sundqvist (KU Leuven, Belgium)
-
Jorick Vink (Armagh Observatory, UK)
Scientific
organisers
- Jiri Krticka (Masaryk University, Czech
Republic)
- Nevena Markova (Institute of Astronomy with NAO,
BAS, Bulgaria)
- Joachim Puls (Universitäts-Sternwarte,
Muenchen, Germany)
- Jorick Vink (Armagh Observatory,
UK)
Weblink:
http://eas.unige.ch/EWASS/session.jsp?id=SS10
Email:
krticka@physics.muni.cz
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10 - 13 July 2017
Venue: Nice
This
conference aims at gathering researchers working in the domain of
evolved stars, be it low mass or high mass, i.e. AGB, LBV, Delta
Scuti, WR, sgB[e], etc. This will foster fruitful discussions and
exchanges between stellar physicists. The first of this conference
series has been organized in 2015 in Nice, and it was dedicated to
the memory of Olivier Chesneau, a young stellar physics scientist who
was at the origin of many collaborations. To get a sense of the
topics discussed during this first conference, you can browse the
presentations of the 2015 conference, or take a look at the published
proceedings.
Weblink:
https://poe2017.sciencesconf.org/
Email:
fmillour@oca.eu
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June 19 - 23, 2017
Venue: University
of Pittsburgh, Pittsburgh, PA, USA
A five-day workshop
which will bring both observational and theoretical researchers
together to discuss massive stars, LBVs, and Supernova (SN) Impostors
will be held June 19 - 23, 2017 at the University of Pittsburgh.
With the advent of new surveys, many more SN impostors
and peculiar SNe are being found. These discoveries are challenging
our current understanding of massive star evolution. Some of the
questions we intend to address at the workshop are:
What is the
relationship between massive stars, LBVs and SN impostors?
What
can current observations tell researchers about massive star
evolution and instabilities?
Are Type IIn SNe related to
classical LBVs or do they arise from another mechanism?
Do LBVs
originate from the most massive stars?
Is binarity required for
a star to go through the LBV stage?
How important is inflation
for massive star outbursts?
How do massive stars influence
enrichment leading to molecule and dust formation?
Our
tentative schedule, intended to maximize discussion at each stage,
will devote the first three to four days to massive stars, LBVs and
SN impostors in general. The last one to two days will focus more on
Eta Carinae, one of the most enigmatic objects in our local group of
galaxies and one of the most massive and luminous stars in our galaxy
that is conveniently in the LBV stage. Despite extensive
investigations we still have many outstanding questions: Which star
underwent the outburst? What caused the outburst? How much material
was ejected? What is the enriched ejection telling us about molecules
and dust formation? Were there only the 1840s and 1890s events, or
were there previous massive ejections in addition to the pre-LBV
winds? What is the evolutionary stage of the secondary star?
The
workshop will examine how this massive binary fits into our
understanding of these questions and discuss the studies, both
theoretical and observational, that are needed as the 2020 periastron
event approaches. We will also address what other massive stars, LBVs
and SN impostors can and should be studied to provide new
insights into massive star evolution.
A block of rooms
has been reserved at Hilton Garden Inn Pittsburgh in Oakland
(Pennsylvania), which is within walking distance of the conference
room. Details will be placed on the conference website at
http://kookaburra.phyast.pitt.edu/hillier/Eta2017_workshop in
the near future. There is no registration fee.
As
attendance is limited to approximately 35 participants, all attendees
must be approved by the Scientific Organizing Committee. If you are
interested in attending the workshop, and in presenting a talk,
please send an email to John Hillier at hillier@pitt.edu. Please use
the words "Pittsburgh Workshop" in the subject
line.
Weblink:
http://kookaburra.phyast.pitt.edu/hillier/Eta2017_workshop
Email:
hillier@pitt.edu
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