ISSN 1783-3426
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s-process production in rotating
massive stars at solar and low metallicities
Spectroscopic
and Photometric Variability in the A0 Supergiant HR 1040
IAU Commission 36 (Theory of Stellar Atmospheres): Hexennial Report 2009-2015
Two PhD positions in asteroseismology of massive stars at Leuven University
Electron
Capture Supernovae & Super-AGB Star Workshop
IAUS
329: The Lives and Death-Throes of Massive Stars
Urs Frischknecht (1,2), Raphael Hirschi (1,3,8), Marco
Pignatari (4), André Maeder (5), George Meynet (5), Cristina
Chiappini (6), Friedrich-Karl Thielemann (2), Thomas Rauscher
(2,7,8), Cyril Georgy (1), Sylvia Ekström (5)
(1) Keele
Uni, (2) Uni Basel (3) Kavli IPMU (4) Konkoly Obs (5) Geneva Obs (6)
AIPotsdam (7) Uni Hertfordshire (8) BRIDGCE UK network
Rotation
was shown to have a strong impact on the structure and light element
nucleosynthesis in massive stars. In particular, models including
rotation can reproduce the primary nitrogen observed in halo
extremely metal-poor (EMP) stars. Additional exploratory models
showed that rotation may enhance s-process production at low
metallicity.
Here we present a large grid of massive star
models including rotation and a full s-process network to
study the impact of rotation on the weak s-process. We explore
the possibility of producing significant amounts of elements beyond
the strontium peak, which is where the weak s-process usually
stops.
We used the Geneva stellar evolution code coupled to a
large reaction network with 737 nuclear species up to bismuth to
calculate 15-40 M☉ models at four metallicities
(Z=0.014, 10-3, 10-5, and 10-7) from
the main sequence up to the end of oxygen burning.
We confirm
that rotation-induced mixing between the convective H-shell and
He-core enables an important production of primary 14N,
22Ne and s-process at low metallicity. At low
metallicity, even though the production is still limited by the
initial number of iron seeds, rotation enhances the s-process
production, even for isotopes heavier than strontium, by
increasing the neutron to seed ratio. The increase in this ratio is a
direct consequence of the primary production of 22Ne.
Despite nuclear uncertainties affecting the s-process
production and stellar uncertainties affecting the rotation-induced
mixing, our results show a robust production of s process at
low metallicity when rotation is taken into account. Considering
models with a distribution of initial rotation rates enables to
reproduce the observed large range of the [Sr/Ba] ratios in
(carbon-enhanced and normal) EMP stars.
Reference: article
to be published in MNRAS
Status: Manuscript has been
accepted
Weblink:
http://adsabs.harvard.edu/abs/2015arXiv151105730F
Comments:
26 pages, 15 figures, 8 tables
Email:
r.hirschi@keele.ac.uk
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David J. Corliss (1,2), Nancy D.
Morrison (2), and Saul J. Adelman (3)
1 - The University
of Toledo; 2 - Wayne State University; 3 - The Citadel
A
time-series analysis of spectroscopic and photometric observables of
the A0 Ia supergiant HR 1040 has been performed, including equivalent
widths, radial velocities, and Strömgren photometric indices. The
data, obtained from 1993 through 2007, include 152 spectroscopic
observations from the Ritter Observatory 1 m telescope and 269
Strömgren photometric observations from the Four College Automated
Photoelectric Telescope. Typical of late B- and early A-type
supergiants, HR 1040 has a highly variable Hα profile. The star was
found to have an intermittent active phase marked by correlation
between the Hα absorption equivalent width and blue-edge radial
velocity and by photospheric connections observed in correlations to
equivalent width, second moment and radial velocity in Si II λλ6347,
6371. High-velocity absorption (HVA) events were observed only during
this active phase. HVA events in the wind were preceded by
photospheric activity, including Si II radial velocity oscillations
19–42 days prior to onset of an HVA event and correlated increases
in Si II Wλ and second moment from 13 to 23 days before the start of
the HVA event. While increases in various line equivalent widths in
the wind prior to HVA events have been reported in the past in other
stars, our finding of precursors in enhanced radial velocity
variations in the wind and at the photosphere is a new
result.
Reference: AJ, 150, 190
Status: Manuscript
has been accepted
Weblink:
http://iopscience.iop.org/article/10.1088/0004-6256/150/6/190
Email:
nancy.morrison@utoledo.edu
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Joachim Puls & Martin
Asplund
(1) University Observatory, LMU Munich, Germany
(2) Research School of Astronomy & Astrophysics, ANU,
Canberra, Australia
This hexennial report covers the
activities of IAU Commission 36 -- 'Theory of Stellar Atmospheres' --
during the years 2009 to 2015, and will be the last report from this
Commission, being replaced by Commission C.G5.
After
outlining the composition of the Organization Committee(s), we list
the scientific meetings held between 2009 and 2015 that were of
relevance for our Commission members, and comment on the
establishment and objectives of the new Commission C.G5 ('Stellar and
Planetary Atmospheres') within the re-structuring process of the IAU.
In the main part of the report, we briefly review specific
contributions and achievements within our research field during the
last six years, concentrating on the theoretical aspect, and dividing
between late-type and massive star atmospheres. We also provide a
more general overview of primary research areas, and finish our
report with a collection of useful web links.
Reference:
Transactions IAU, Volume XXIXA
http://arxiv.org/abs/1512.06972
Status: Manuscript has been
accepted
Weblink: http://arxiv.org/abs/1512.06972
Email:
uh101aw@usm.uni-muenchen.de
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Conny Aerts
Institute
of Astronomy
Celestijnenlaan 200D
3001 Leuven
Belgium
MAMSIE is an ERC Advanced Grant in stellar physics
(2016-2020) with the aim to study mixing and angular momentum
transport of massive blue stars. The project consists of several work
packages and relies on the bridging of stellar modelling and 3D
hydrodynamics. As part of the project, two PhD students will perform
seismic modelling of OB-type stars based on non-radial oscillation
modes detected in space photometry and/or ground-based data.
One
PhD student will focus on the development and application of new
modelling
tools for single OB-type gravity-mode pulsators. The
other PhD student will
tackle the case of massive binary
pulsators by performing multicolour photometry and spectroscopic
monitoring with the aim to apply iterative binary and seismic
modelling. Both PhD students will interact intensively with the
MAMSIE postdocs, who will focus on the bridging of asteroseismology
and 3D hydrodynamics. The MAMSIE PI, Conny Aerts, will act as PhD
supervisor:
fys.kuleuven.be/ster/staff/conny-aerts
Attention/Comments:
More information on the institute, the requirements and the
application instructions is available from
http://fys.kuleuven.be/ster/vacancies
Weblink:
http://fys.kuleuven.be/ster/vacancies
Email:
conny.aerts@ster.kuleuven.be
Deadline: 25 February
2016
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February 1-5, 2016
Venue: Monash
University, Melbourne, Australia
We would like to announce the
Joint Institute for Nuclear Astrophysics (JINA) workshop on Electron
Capture Supernovae (ECSNe) & Super-AGB Stars to be held February
1-5, 2016 at Monash University, Melbourne, Australia. This workshop
aims to bring together Australian and international experts from
stellar evolution, supernova theory, stellar spectroscopy,
hydrodynamics, and nuclear physics with expected topics including:
* single and binary super-AGB star evolution
*
population synthesis & ECSNe rate predictions
*
convective URCA phase
* C and O/Ne flame propagation
*
electron capture supernova models
* s/p/r/iprocess
nucleosynthesis
* spectroscopy and GCE role of ECSNe at low
metallicity
* ECSNe from Pop III stars
* evidence for
ECSNe from a) light curves, b) SN remnants c) neutron star masses
*
massive white dwarf formation and super-AGB stars mass loss rates
The preliminary webpage for the meeting can be found at:
http://users.monash.edu.au/~cdoherty/EC-SN-2016/
If you
are interested in participating please register as soon as possible
through our website. Registration is free and we are able to offer
limited financial support for students.
We hope to see you in
Melbourne next February!
Yours Sincerely,
The
Organising Committee
Carolyn Doherty, Alexander Heger, John
Lattanzio and Bernhard Mueller
Weblink:
http://users.monash.edu.au/~cdoherty/EC-SN-2016/
Email:
alexander.heger@monash.edu
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28th November to 2nd December 2016
Venue:
Takpuna, Auckland, New Zealand
Dear colleagues,
This
is the first announcement of the forthcoming IAU symposium to be held
in Auckland, New Zealand entitled
"IAUS 329: The Lives and
Death-Throes of Massive Stars".
Dates: 28th November to
2nd December 2016
Location: Auckland, New Zealand
Venue: The
Spencer on Byron Hotel, Takapuna
Abstract Submission and
registration to open: 30th March 2016
Abstract Submission closes:
30th May 2016
Early-bird registration closes: 30th August 2016
IAU Grant submission deadline: 30th May 2016
Conference
website: http://nzstars2016.nz
Contact for questions about
the meeting scientific program: nztars2016@auckland.ac.nz
The
meeting will summarize recent progress and establish stronger links
between the massive star community and closely-linked fields,
particularly those studying end stages of massive star evolution and
massive star cosmic implications. We will announce the invited
speakers and a more detailed schedule before registration opens but
wanted to provide useful information on the conference while it is
only one year away.
Topics to be covered:
well established facts and open problems in our knowledge of
massive stars, particularly in the so-thought well understood phases
challenges to present theoretical models of interior and
atmospheres; connecting interior and atmospheres; wind structure;
episodic mass-loss mechanisms; binaries in interaction; X-ray and
gamma-ray production
short-lived phases of massive stars
(LBVs, WRs and RSGs) and their characteristics as supernova
progenitors
new results from large-scale surveys,
observational techniques and instrumentation for massive stars and
supernovae
the link between massive stars and their deaths
constraints on the nucleosynthesis production in supernovae
and the production of dust
explosion mechanisms of supernovae
and the parameters required for a successful explosion
massive
stars as astrophysical tools: tracing galaxies’ structure; tracers
of star formation; feedback from massive stars; population synthesis;
limits to our interpretation of the high-z Universe; cosmic
reionization; first stars and galaxies.
Travel, accommodation
and support
New Zealand is a significant distance to travel,
particularly due to the location of the international date line
causing many attendees to "lose-a-day" when travelling to
the conference. We advise our most distant attendees to arrive two
days early, if possible, but at least 1 day before the Monday
morning, so they are able to enjoy the first full day of the
conference.
We are finalizing the accommodation for the
conference but have ensured that people can share rooms to reduce.
Rooms in the conference venue come with kitchenette facilities. Rooms
are NZ$178.25 inclusive of GST per night including wifi we will
provide details of how to book a room in the second announcement. The
conference registration fee is yet to be finalized but including GST
it will be around NZ$575.
We have limited funds from the IAU
to provide support for attendees that have limited travel funding.
Further details of how to apply for this funding will be provided
shortly.
Please contact the organizers if child care is
required. We are currently in discussion with local providers.
If
you require a letter of invitation to visit New Zealand, you must
first register for and pay all applicable registration fees. Full
details of how to apply for this letter and a list of visa-free
countries are listed on the conference website.
Nationwide
public symposium
In the weekend following the conference, Dec
3rd, we are planning to run a large one day public symposium with as
many speakers as possible talking about their latest research. We
also hope to have these talks streamed live onto the internet and
recorded so there is a lasting impact of the meeting in New Zealand.
If you would like to be involved, or perhaps to travel to a city
within New Zealand to give a talk please email
j.eldridge@auckland.ac.nz and outline your previous outreach
experience.
Splinter Meetings:
It may be possible to run a
few splinter meetings during the conference in the evenings, or
during the weekend after the main conference. If you would like to
run a splinter meeting please email j.eldridge@auckland.ac.nz with a
short outline of the topic, an estimated number of participants, and
the names of organizers before the 30th March 2016.
Conference
Excursions:
We currently aim to provide a choice for were to go in
the conference excursions on Wednesday afternoon. We hope to have a
trip to a nearby Auckland vineyard, a trip to the Auckland Domain
Museum and possibly a beach Olympics.
Social Media:
The
hashtag for the meeting is #NZstars2016. We have also setup a
Facebook group for the meeting which can be found at:
https://www.facebook.com/groups/1015095635200645/
Conference
Equity and Anti-Harassment Statement:
#NZstars2016 is dedicated to
providing an equitable and harassment-free conference experience for
everyone regardless of gender, gender identity and expression, sexual
orientation, disability, physical appearance, body size, race, age or
religion. We do not tolerate harassment of conference participants in
any form. Conference participants violating these rules may be
sanctioned at the discretion of the conference organizers and the
conference equity committee.
Weblink:
http://nzstars2016.nz
Email:
nzstars2016@auckland.ac.nz
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