Evolution offor
Planetary
Nebulae:
analysis & numerical
Application
funding
the research
projectmodels
Evolution of Planetary
Nebulae: analysis &
numerical models
Evolution Planetarischer Nebel: Analyse & numerische Modelle
Applicant:
A.Univ. Prof. Dr. Stefan Kimeswenger
Co-Investigator: Ass.Prof. Dr. Ralf Kissmann
Institute for Astro- and Particle Physics
University of Innsbruck
Technikerstrasse 25
A-6020 Innsbruck
Austria
13.02.2014
Evolution Planetarischer Nebel: Analyse & numerische Modelle
Title image: The multiple shell planetary nebula NGC 2438 as seen in H [N II] (left) and in [O III] (right). As
the intensity range covers more than 3 orders of magnitude between the main nebular rim and the halo, the images
were scaled logarithmically. The middle panel shows the ratio of the two images. The ratio varies only by a factor of
two. The dark clumps along the edges of the rim and the halo are the accentuation of the low excitation clumps in [N
II].
Adopted from: Dalnodar & Kimeswenger, Proceedings of ‘Asymmetric Planetary Nebulae 5 ’ held in Bowness-onWindermere, U.K., 20 - 25 June 2010, A.A. Zijlstra, F. Lykou, E. Lagadec and I. McDonald eds., A81 (2011) ebrary ©
Jodrell Bank Centre for Astrophysics
Evolution of Planetary Nebulae: analysis & numerical models
Introduction
Planetary nebulae (PNe) are a very special laboratory in space. Just like other kinds of ionized nebulae such as H II
regions, supernova remnants, the physics of ionized gases has been extensively studied in such objects from the
beginning of their first spectroscopic observations. As long as the assumption of equilibrium holds (thermal and
ionization), the theory of PNe is considered largely understood (Osterbrock & Ferland 2006). Although the standard
textbook model of the colliding two wind system proposed by Kwok (Kwok et al. 1978; Kwok 1982, 2007) is still the
basis of our understanding, deeper insights show, that it can`t be that simple.
Their typical optical thickness near unity, positioning them thus between the optically thick stellar atmosphere and
the optically thin interstellar matter (ISM) regime, makes modelling as well as interpretation of observations rather
difficult. In this proposed research project we intend to proceed towards a more general model of the PNe evolution.
Moreover, we combine the expertise of experienced observers around the PI Stefan Kimeswenger, with a developer
of a numerical MHD code around CoI Ralf Kissmann within one team.
Due to the double affiliation with a Chilean institute, the PI has extensive access to European and US facilities hosted
in Chile as well as access to own facilities of the Universidad Católica del Norte (UCN) without delay through a time
allocation committee (TAC).
The CoI developed the numerical magneto hydrodynamic (MHD) code Cronos in close collaboration with various
other groups. It was adapted and successfully applied to a wide variety of problems in astrophysics such as stellar
wind outflows and turbulence in accretion discs and in interstellar matter. This allows unique access for adapting the
code down to the Riemann solver level, and thus not only as usually done as add-on plugins around a black box of
the internal routines.
This in-house collaboration started a few years ago leading to the preparation studies for this project in a PhD and a
MSc thesis strengthening the link between theory and observation. This connection in one team instead of the more
often used loose bridge between individual theoretical and observationally working team is one of the major
strengths of this project.
In this proposal we focus on three major subprojects:

Observation and static modelling of (nearly) spherical PNe at various stages, with a focus on the spherical
multiple shell PNe (MSPNe).

Radiation-Hydrodynamic modelling of PNe evolution to get new insights in energy and radiation transport
and balance over the main part of the evolution (until the nebulae get completely optically thin).

A dedicated investigation of the extremely fast evolving carbon rich very late helium flash/pulse (VLTP)
objects – also called born-again nebulae.
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Evolution of Planetary Nebulae: analysis & numerical models
1
Scientific aspects
1.1 Current status of the research
PNe are the ionized ejecta from asymptotic giant branch (AGB) stars running into the neutral material ejected during
the last phases of severe mass loss of the star. They are a short-lived phenomenon compared to typical stellar
lifetimes, and are visible while the now post-AGB star quickly crosses the Hertzsprung-Russell diagram (HRD)
towards high temperatures, before entering the white-dwarf cooling track. Most of the luminous material originates
from the stellar wind during the last thermal pulses on the AGB. It is believed, although recently under some debate,
that the vast majority of stars with initial masses between 0.8 and 8 solar masses (M) eject their remaining shell at
the end of their lifetime to form a PN (Kwok 2007). The stellar core (central star; CSPN) remains as an early stage hot
white dwarf (WD), photo ionizing this nebula. Moreover, if a VLTP event occurs on the WD cooling track, additionally
a second, extremely carbon rich PN is ejected (see Hajduk et al. 2005).
The whole event, until the shell is diffused in the ISM, lasts a only few 10 000 years.
The standard PN model (Kwok et al. 1978; Kwok 1982, 2007; Okorokov et al. 1985) assumes a spherical shell with a
wind from the CSPN quickly decreasing its mass load but increasing its speed from about ten km/s up to a few
hundred km/s or even excessing two thousand km/s in some cases. The ionization and thermal energy balance is
dominated by radiation processes (photon dominated region: PDR). In these models, the transport of this radiation is
assumed to be isotropic to achieve (1D) spherical symmetry. The currently best state of the art models of this type
are those by the group around D. Schönberner (Kifonidis, 1996, Schönberner & Steffen, 2002; Corradi et al. 2000,
2003; Perinotto et al. 2004). These models provide a very good representation of the observed integrated surface
brightness. The related setup (Fig. 1) includes a slight deviation from a pure constant mass loss wind during the last
AGB pulse, using a semi empirical mass-loss luminosity relation on the AGB.
Fig. 1: AGB wind model used by Perinotto et al. (2004) at the start of the simulation. Left: A constant
stellar mass loss during the AGB; Right: result of an AGB wind evolution including thermal pulses. Both
are assuming a neutral material and a sudden onset of the fast wind (thick line: heavy particle density;
dotted line: electron density; thin line: flow velocity).
The onset of the fast wind causes an expanding supersonic shock front running into the remnant AGB wind material
forming the main rim of the PN. The onset of the hard UV radiation from the hot WD causes a large fraction of the
ionization of the nebula. CSPN parameters (wind, mass loss, temperature, …) are well modelled (see Perinotto et al.
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Evolution of Planetary Nebulae: analysis & numerical models
2004). Observational studies show that the expanding shock fronts (Guerrero et al. 2013) break up the structures
even in fairly symmetric nebulae, thereby causing clump formation. This leads to leaking of hard ultraviolet (UV)
radiation through the inner shell and thus a much higher ionization rate further out in the nebula. Although these
models suffer from ignoring and not modelling these effects they are often noticed as the best available dynamic
model.
All the effects described above can be best studied at nearly symmetrical multiple shell and halo PNe (MSPNe), as
the surrounding stellar material from the final mass loss of the AGB wind is observable too. Thus they were already
picked as benchmark nebulae in the models of Schönberner and his group. Such observational studies, however,
represent a single snapshot in time only. They (WER IST ‘they’?) compare their observations by using static
photoionization models like e.g. CLOUDY (Ferland et al 2013). As was shown by Schönberner (2008), the timescales
for the photon dominated processes are much shorter than those of the hydrodynamic evolution. Thus these kind of
models should give reliable results for the energy balance and the plasma ionization level of the nebulae at this
moment in the dynamic evolution. A deep study of these effects for NGC 2438 and an extensive discussion can be
found in the recent paper by Öttl et al. (2014b). This study clearly showed that the temperature profile does not
follow the predictions of a recombination halo proposed e.g. by Corradi et al. (2000) obtained in the previous 1D
hydrodynamic models. The UV radiation leaking by the low filling factor adds an enormous energy load to the outer
regions (Wie hängt das mit dem davor zusammen?). This finding has been claimed by Schönberner et al. (2014), not
to be in conflict with the previous studies
Fig. 2: Left panel: Shadowing effects in NGC 2438 as seen in Hubble Space Telescope (HST) images. The
lines point to the direction of the central star; Right panel: the increase of the electron temperature.
crosses: calibration of Osterbrock & Ferland (2006); bars: calibration of Proxauf et al. (2014) (taken from
Öttl et al. 2014b).
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Evolution of Planetary Nebulae: analysis & numerical models
García-Segura, G. et al. (2006) started a 2D study where they showed the breakup of the fronts, leading to similar
structures, as they are seen in observations (see Fig. 2). These simulations show small dense clumps at the inner
edge and large smooth structures outwards. The latter might be partly due to the fairly low resolution used for the
model. But moreover hydrodynamic numerical studies from other field in physics although show, that 2D models
force due to the plane vortices more the larger structures (they call it conservation of enstrophy), while real 3D
models allow the formation of realistic size distributions with a larger number of small fractals (see reviews by
Boffetta & Ecke (2012) and Tabeling (2002) and references therein).
The timescales for the complete breakup of the front and the build-up of leaks in the main rim are about a factor of
2 faster, than the evolution in the 1D models. Despite the problems mentioned above, these 2D models are,
therefore, a good starting point for further studies.
Fig. 3: 2D models by García-Segura et al.
(2006) showing the break-up of the nebular
rim by instabilities caused by the fast wind
colliding with the AGB material
The observations of Speck et al. (2003) and Matsuura et al. (2009, 2011) show this evolution towards smaller and
smaller structures when going outwards in the nebula (Fig. 3).
Fig. 4: Zoom into the Ring Nebula (left) and the Helix Nebula (right) by Matsuura et al. (2009, 2011).
While the inner zone contains distinct clumps with shadowing effects, the outer ring only shows
numerous crescents without tails.
A very special case of PNe evolution certainly is that of the born again nebulae. Thermal pulses (helium flashes)
dominate the last phase of the AGB evolution. At this time the energy generation is via hydrogen shell burning,
punctuated at regular intervals (104 - 105 yr) by helium flashes followed by short phases of quiescent helium burning.
In a significant fraction of stars (10 - 20%), a final helium flash occurs on the WD cooling track after already a normal
PN has been evolved: a VLTP (Zijlstra, 2002). This causes the re-ignited star to retrace its evolution, briefly becoming
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Evolution of Planetary Nebulae: analysis & numerical models
a born-again red giant. Due to the short lifetime of the phenomenon only two such objects were observed directly:
V605 Aql in 1918 and V4334 Sgr (Sakurai's object) in 1996. Observations have now led to significant improvements in
theoretical models. The physics behind it, is currently further investigated by constructing detailed 3D hydrodynamic
simulations of the core (Herwig et al. 2014). Due to the unusual carbon rich chemistry the evolution is much faster
than for normal PNe (Koller & Kimeswenger, 2001, Clayton et al. 2006). This is caused due to the enormous optical
depth and thus the high radiation pressure of this extremely metal rich material. Furthermore the newly evolved
second PN not runs into a neutral AGB wind material, but into a thin hot inner bubble of the previous PN causing
more or less no pressure against the new ejecta.
Fig 4: (upper left) The green light continnum imaging (5x5”) of V605 Aql by Clayton et al. (2013)
dominated by C IV wind line emission; (lower left) The NTT spectroscopy and identifying by veleocity
seperation individual components and the real center of the source (Kimeswenger et al. 2008); (upper
right) The brand new adaptive optics (AO) observations of V4334 Sgr by Hinkle & Joyce (2014) showing a
dramatic change of the Ks image from 2010 September to 2013 April. (lower right) The [C I] 985.1 nm
line from a slit image obtained by the same authors showing spatial vs. veleocity segregation.
1.2 Preparation Study
The team has obtained during the recent years a feasibility study for the proposed research project. Although it is
now clear that a binary formation pathway is responsible for the formation of a significant fraction of the PNe (Jones
et al. 2014) and thus a large fraction of PNe is not spherical, we first focused on the classical evolution spherical
evolution. The asymmetries and the formation process of those is not the focus of this project as we first try to
understand the complex mechanisms in the spherical nebulae. Imaging of spherical nebulae and nebulae with only
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Evolution of Planetary Nebulae: analysis & numerical models
small deviation from spherical symmetry shows strong effects of dense clumps und UV leaking through a thin
material between the clumps.
1.2.1
Observational Studies and static photoionization Modelling
The team successfully collected observations from various resources to obtain deep insights into the thermodynamic
state of the nebulae – both, MSPNe like NGC 2438 (see Öttl et al. 2014b) as well as for the born-again nebulae V605
Aql (intermediate resolution from European Southern Observatory (ESO) New Technolgy Telescope (NTT) spectra;
Lechner & Kimeswenger 2004 & some unpublished high resolution data obtained by the applicant) and a large grid
of ESO Very Large Telescope (VLT) spectra (7-9 h per observing season) and radio observations using the Very Large
Array (VLA) for V4334 Sgr (Sakurai’s star) over a full decade during it´s on going re-ionization. The latter is part of the
international collaborations with Peter van Hoof (Brussels) and Albert Zijlstra (Manchester). The data was only briefly
analysed, but is mostly waiting for detailed investigation and analysis (van Hoof et al. 2014). Further deep
spectroscopy is applied for currently already at 6.5 to 8m class telescopes to obtain deeper spectra in the outskirts,
haloes and shells. To improve the interpretation, recently new diagnostic diagrams for the forbidden line emission,
using modern state of the art atomic data, were calculated by Proxauf et al. (2014). Atacama Large
Millimeter/submillimeter Array (ALMA) observations were granted recently for Cycle 2 for V4334 Sgr. The latest
CLOUDY modelling of the MSPNe was able to predict all spectral lines, only by fitting parameters like the density
profile and the filling factor using a few well exposed lines of Oxygen, Hydrogen and Helium. These predictions are in
good agreement with observations in intensity and in spatial distribution (see Fig. 5 taken from Öttl et al. 2014b).
Fig. 5: Model of NGC 2438 (Öttl et al.
2014b).
dashed:
model;
solid:
observations. The spectral lines in
panels a) and b) were used to fit
model parameters. Panels c) and d)
show the resulting predictions in
comparison with data for other
prominent lines.
The energy balance of PNe is dominated by photoionization and radiative cooling, although shock fronts moving
through the medium might play an essential role at the boundary layers (see e.g. Corradi et al. 2003, 2007 and
Perinotto et al. 2004). Investigations normally use the diagram of line ratios log(H/[N II])) vs. log(H/[S II]) to
identify shock excited regions, as they are found in supernova remnants (SNRs) or in H II regions (shocked by massive
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Evolution of Planetary Nebulae: analysis & numerical models
stellar winds), from the mainly photoionized gas of PNe. This scheme was introduced by Garciá-Lario et al. (1991)
and refined in Magrini et al. (2003).
Recently Guerrero et al. (2013) showed, using HST images, that in regions with higher temperature, where the low
ionization species [N II] and [S II] are not sufficiently abundant, the [O III] / H ratio is an even better indicator for
shock fronts1. They mentioned that the F656N images might be strongly contaminated by [N II] emission and thus
had to exclude many nebulae with strong Nitrogen emission from their analysis. We extended the method (Öttl et al.
2014b), to overcome this situation, additionally using observations with the F658N filter. If also the F673N image was
taken with HST, we are furthermore able to extend the Magrini et al. (2003) study into full 2D (Fig 6.). This allowed
identifying shock features with two independent methods, using low excitation species as well as high excitation
ions.
Fig 6: The shock tracer analysis of NGC 2438 from Öttl et al. (2014b). Left panel: the classical diagram
after Magrini et al. (2003) extended to a spatially resolved investigation along the E-W slit through the
whole nebula. Right panel: the new [O III] / H diagram in 2D after Guerrero et al. (2013) showing a
nearly constant line ratio on case of this classical benchmark MSPNe
1
They used the HST filters F656N (around H) and F502N ([O III]).
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Evolution of Planetary Nebulae: analysis & numerical models
1.2.2
Radiation Hydrodynamic modelling
During the last two years we worked on the investigation of the dynamical evolution of PNe by hydrodynamic
modelling mainly using the CRONOS code. This code is a fully MPI parallel MHD code developed by the CoI Ralf
Kissmann. It contains different Riemann solvers and was successfully applied to a wide variety of astrophysical
systems (for an extensive summary see Kissmann, 2014a). We have chosen this code as we are able to easily adapt it
to our problems and modify core components of the code if necessary. Other codes are mostly black boxes where
we are only able to add plugins. In his MSc thesis Felix Niederwanger adopted CRONOS to the needs of PNe
modelling. He studied numerical stability and reliability of the code for our purpose by using various model setups.
Radiative terms will be treated by using CLOUDY. The latter has been studied during the last two years in the PhD of
Lars Hunger (Hunger et al. 2014a). High density contrast clumps, as found observationally in various studies (see Fig.
3 above) would require very high resolution, and thus a large computational effort, when they are implemented
directly. Thus sub-grid physics has to be studied and incooperated to the energy and momentum at the global level
calculations as source- and sink terms. As a first step towards modelling dynamical effects using radiative transport
we investigated the fast evolution of born again nebulae, using an own electron recombination code (Koskela et al.
2012) by extending the method in Binette et al. (2003).
The implementation of source and sink terms for the CRONOS codes has been tested by various models in the MSc
thesis of Felix Niederwanger (Niederwanger et al. 2014, Niederwanger 2014). For this purpose a central (unresolved)
object, representing the stellar core and emitting a possibly variable wind was included in a 3D model of a PN. Here,
Cartesian coordinates were chosen to hand avoid correction terms in the equations, and to avoid imprinting the
expected geometry of the result already in the setup. First tests covered the onset of the evolution. For that purpose
an unphysical density profile proportional to 1/r and a steady state velocity field was introduced. Then a constant
mass loss wind was introduced at the centre of the computational domain. Despite the choice of Cartesian
coordinates and the appearance of an artificial shock front by this sudden onset of the wind, the solution converges
to the expected one. At the very inner boundary a marginal deviation (only a few per cent) in the onset region of the
wind into the outer material is visible (Fig. 7).
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Evolution of Planetary Nebulae: analysis & numerical models
Fig. 7: Test for the inner boundary conditions in our hydrodynamical PN model (at a radial
distance of 1 pc here) for the outflowing wind. Left panel: The wind evolves to the expected
density profile, representing a constant mass loss. Right panel: Shock front at time: … showing a
density contrast of a factor of 2. Even such a low resolution model (1283 gridpoints) produces
only small deviations from spherical symmetry.
As often seen in observations, PNe have tori of dense material. Although the origin of those is not clear yet
(equatorial wind enhancements during the AGB wind phase, disks from the orbital motions of planets of binary
companions, …) we investigated the numerical stability of our code in the presence of such structures showing stong
spatial gradients. As the most general test, we introduced a disk offset from the centre of the computational domain
and inclined by 17 degrees. For this setup we found that the code conserves the symmetry of the disk, even though
the disks symmetry axis was inclined with respect to the numerical grid.
Fig. 8: Test case using a torus of dense material displaced from the centre of the numerical
domain and inclined by an angle of 17° at low resolution (643). Left: Initial conditions. Right:
Bipolar outflow lobes resulting from the interaction of the injected spherical CSPN wind with
the disk. The sharp edge at the right-hand side is the limit of the computational domain.
Additionally, we used a model with a torus to investigate the effects of the spatial resolution and the onset of the RT
instabilities expected to result from the interaction of the CSPN wind with such a torus (see Fig. 10). This result can
be viewed as the extension of the work of García-Segura et al. (2006) (see Fig. 3) to three spatial dimensions. The
study shows the lower limits for the resolution in corresponding numerical simulations.
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Evolution of Planetary Nebulae: analysis & numerical models
Fig. 10: Left: Evolution of a spherically symmetric stellar wind colliding with a dense torus. Results are
shown for resolutions of 643, 1283 and 2563 grid points (from left to right). The resulting instabilities not
only form broken main fronts, but also clumpy structures in the surrounding media. Right: HST image of
the Engraved Hourglass Nebula, a young PN in the southern hemisphere. (Image credits: NASA, R. Sahai,
J. Trauger (JPL), and The WFPC2 Science Team)
1.3 Methods and Goals
As we have seen in the previous sections, our current understanding of PNe is that 1D or even 2D models of PNe
cannot accurately describe the complex plasma physics of such objects. Therefore, it is necessary to introduce both
fully 3D numerical models of such objects and also related to their complex spatial structure in observations.
Consequently, in this project we will develop a full 3D radiative transfer hydrodynamic model of the evolution of the
PNe shell from the late post-AGB / early proto-PNe stage until the WD cooling track in the HRD has reached the point
beyond that a VLTP is not expected to occur any more. This model will allow us to describe the evolution of PNe
shells and also the thermodynamic state of the nebula at the moment when the VLTP explosions take place.
These modelling efforts will be combined with observational studies for testing the predictions, which will also
supply the boundary conditions and the parameter ranges for the models. The relevant data will be obtained by
deep observational studies of the outskirts of MSPNe. The double affiliation of the applicant in Chile will allow us to
get access to larger observational data sets. Corresponding applications are already submitted to various ESO and US
facilities.
The resulting models will then be applied to the highly asymmetric ejecta of the born-again nebulae (see
Kimeswenger et al. 2008), allowing us to (dynamically) model the new ALMA observations granted already in Phase 2
and expected to be taken in summer 2014.
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Evolution of Planetary Nebulae: analysis & numerical models
(Hier Definition der Subprojekte??)
1.3.1
Subproject: Observations and Analysis
Shock Analysis of PNe using HST Images:
The energy balance of PNe is dominated by photoionization and radiative cooling, with shock fronts moving through
the medium possibly playing an essential role at some boundary layers. The recent studies of Guerrero et al. (2013)
suffer from the [N II] contamination. We showed in Öttl et al. (2014b), that one can overcome this, if the F658N
images also were taken for the nebulae (see Fig. 10). We also showed that, if also the F673N image was taken, the
Magrini et al. (2003) study extended fully in 2D can be obtained.
We will investigate those nebulae excluded from the study by Guerrero et al. (2013) due to strong [N II] lines – and
here especially the (nearly) round MSPNe which are our main targets. For this purpose we remove the [N II]
contamination by using the image from the F658N filter. The absolute calibration required for this reduction, will be
transmission
compared by the flux in long slit spectra from various archive sources.
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
F656N
F568N
651
653
655
657
659
661
663
665
667
wavelength [nm]
Fig. 10: HST filter response curves as measured post-mission in lab for F656N and F658N. The grey
underlying dashed curve gives the spectrum of NGC 2438 with a resolution of R ≈ 950 form South
African Astronomical Observatory (SAAO) 1.9m.
With our new method we will also re-investigate the control group of MSPNe showing a thin skin/layer of shocked of
material in the outskirts in the study by Guerrero et al. (2013) to verify the stability of this new analysis. Everywhere,
where we also have the sulphur image, we also will obtain the classical analysis extended to 2D. Table 1 shows the
available filters for all those nebulae.
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Evolution of Planetary Nebulae: analysis & numerical models
Tab. 1: HST archive data of different PNe relevant to the project. Those PNe than can undergo our
revised analysis following Öttl et al. (2014b) are marked in boldface. Nebulae with underlined IDs also
allow the classical study according to Garciá-Lario et al. (1991) / Magrini et al. (2003).
Nebula for this study (excluded by Guerrero et al. 2013)
ID
NGC 2438a)
NGC 2818
NGC 3132
NGC 6537
IC 4406
Mz 3
M 2-14
K 4-55
Hb 5
H 2-15
H 1-9
a)
F656N
F658N
F673N
F502N
H + [N II]
[N II]
[S II]
[O III]












































Control group (Group B in Guerrero et al. 2013)
ID
NGC 1501
NGC 2371
NGC 3242
NGC 6153
NGC 6818
NGC 6826
NGC 7009
NGC 7662
F656N
F658N
F673N
F502N
H + [N II]
[N II]
[S II]
[O III]
































already contained in the pilot study of Öttl et al. (2014b)
The PNe listed in table 1 cover a wide range of evolutionary states from medium excitation objects shortly after the
post-AGB phase, down to the first part of the WD track, where according to the current 1D hydrodynamic models
the effects due to shocks should already diminish. Thus it will provide a more complete view on the evolution of
shocks in PNe along the HRD. We intend to study not only the qualitative appearance, as done in Guerrero et al.
(2013), but also the correlation of the shock strength to other physical parameters like dynamic age, electron
temperatures and densities, abundance deviations found by other studies, etc. This part of the study will be carried
out by the PI with an MSc student.
Spatially resolved photoionization studies of PNe using own spectroscopy and archival data:
We intend to study a whole group of MSPNe spectroscopically and by means of CLOUDY photoionization models. For
this purpose we will use both own observations (currently already ESO applications for some nebulae are submitted)
and archive data (mostly from the ESO archive, including STIS HST spectra for some PNe). Although the spectroscopic
sample from various telescopes and instruments will have to be combined, our previous studies show only small
effects of inhomogeneity on the CLOUDY results (e.g. Lechner & Kimeswenger, 2004, Emprechtinger et al. 2004,
2005). Especially in Öttl et al. (2014b), where we combined ESO 3.6m EFOSC data and spectra from the SAAO 1.9m
for one target, show that a proper handling of the data reduction allows a homogeneous set of results.
The observations will be interpreted using models generated by the photoionization code CLOUDY, being one of the
most sophisticated freely available photoionization codes. We used fits to the radial density distribution and the
filling factor, giving an estimate for the clumpiness of the material, to describe the [O III], H (or H), He I and He II
lines. Only by fitting these parameters and adopting abundance corrections in case of H poor CSPNe allowed us to
reproduce all other emission lines. Only in case of other excitation processes than photoionization (e.g. shocks
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Evolution of Planetary Nebulae: analysis & numerical models
identified in the first part of the observational study) will we additionally have to correct for them in specific
boundary regions or exclude those regions from the fitting. Thus a spatially resolved shock study mentioned before
is so essential in combination with the proposed analysis. This part of the study will be carried out by the Post-Doc.
CLOUDY and CMFGEN wind studies of the born-again PNe V4334 Sgr, V605 Aql and possibly IRAS 15154-5258:
The cores of the VLTP (or born again) PNe will be studied by spectroscopy in various directions. As shown in Clayton
et al. (2013) for V605 Aql the extent of the central source is sufficiently high, that the proposed segregation by
velocity vs. position along the slit (Kimeswenger et al. 2008) will work. Hinkle & Joyce (2014) even applied that very
recently for near infrared lines in V4334 Sgr. We intend to enhance this study by, systematically step with a narrow
slit over the central region using a slit direction alsong the axis of the object, but also perpendicular to it (Solf´s
method introduced already in the 70-ties at Calar Alto for Herbig-Haro objects and later recovered by Hartigan et al.
(2000) and Hartigan (2003) with HST STIS). This will allow us to study the spatial extent of the various velocity
components by applying the method to the whole spectral range and thus the steady changing optical forbidden
lines (van Hoof et al. 2008) as well as the C III and C IV wind lines and contamination by straylight at the dust. The
latter would make spectropolarimetry attractive. We will try to apply for that too, but the expected low signal to
noise ratio will make it difficult to convince a time allocation committee. These observations will be modelled by
using CLOUDY but also possible for the inner Wolf-Rayet wind an analysis with CMFGEN2 or FASTWIND3. The tradeof
will be investigated on the basis of the recent study by Massey et al. (2013). This part of the study will be carried out
by the PI and the proposed post-Doc.
1.3.2
Subproject: Hydrodynamic Modelling
To model the dynamical evolution of PNe we will use the CRONOS code, that was developed for the solution of the
system of partial differential equations of ideal MHD, thus also being applicable to the case of pure hydrodynamics.
In general CRONOS solves following the system of partial differential equations (PDEs):
These equations are in order of appearance the continuity equation, the momentum balance, the induction equation
and the energy equation. The dynamic variables are the mass density , the momentum density u, the magnetic
induction B and the total energy density e. The latter is the sum of the internal thermal energy density eth, the kinetic
2
3
http://kookaburra.phyast.pitt.edu/hillier/web/CMFGEN.htm
http://www.usm.uni-muenchen.de/people/puls/Puls.html
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Evolution of Planetary Nebulae: analysis & numerical models
energy density, and the magnetic energy density. Here, the influence of the radiation of the CSPN on the PN plasma
can be incorporated into these equations by prescribing an additional external force f.
The CRONOS code solves this system of PDEs on a discrete mesh specified by the user, where different orthogonal
coordinates can be used. The code uses an unsplit second order semi-discrete finite volume solver, allowing for
different kinds of Riemann solvers. Extensive validation tests using the different Riemann solvers are given in
Kissmann (2014a), Kissmann & Pomoell (2012) and Kissmann et al. (2009). Apart from that, CRONOS was successfully
applied to various astrophysical problems (see, e.g., Kissmann et al. 2008, 2011, 2012, Flaig et al. 2010, 2012,
Reitberger et al. 2014 and Wiengarten et al. 2013).
In our first PNe models we will neglect magnetic field effects, thus using a hydrodynamical description for the
plasma. As the first important step, we will implement a sophisticated treatment of the interaction of the radiation
of the CSPN with the PN plasma by using CLOUDY in a similar fashion as in a previous study on the evolution of
clumps in PNe (see Hunger et al. 2014b).
For this purpose we will repeatedly apply CLOUDY to a slab of plasma with constant temperature and density. From
each of these CLOUDY simulations we will be able to deduce the resulting attenuation of the radiative flux through
the slab and the acceleration and heating rates resulting from the radiation deposited in the plasma. By this we will
compute an extended table holding the absorption rate of the radiation and the acceleration and heating rate of the
plasma for various plasma and radiation conditions. By applying this table to the individual cells of the numerical
domain of our HD simulation, we can then trace the radiation from the central star outwards. By this ray-tracing
procedure we will obtain the correct heating and acceleration of the gas, while the radiation of the star is
consistently absorbed by the plasma. The implementation of this ray-tracing procedure will be done by the PhD
student, where we locate the CSPN at the centre of a numerical mesh using spherical coordinates. To improve the
numerical efficiency of this setup it will be important to realise the ray-tracing procedure in an MPI parallel way.
This phase requires extensive testing of the resulting numerical simulations with regard to numerical instability
including a critical evaluation of the physical results, even though we do not expect significant problems for the
hydrodynamical solver, since the effect of the radiation only enters via via the source terms f. The only other
relevant influence on the PDEs is a change of the mean atomic weight determining the thermal pressure. For this we
only expect a significant change, where hydrogen starts to become ionised. As the ionization resp. the location of the
recombination front in a PNe, being not in local collisional thermodynamic equilibrium, is not that much driven by
the temperature and the thermal energy eth, but by the UV absorption, these quantities still can be calculated from
the external terms of the equations via CLOUDY. After this series of tests, we will be in a position to investigate first
steady state models 3D for the different phases of a PN.
In the next step in this subproject we will work on the transition from steady state model to such that take the
evolution of the CSPN fully into account. For this, the stellar evolutionary tracks for CSPN by Blöcker (1995) and the
mass loss rates calculated form various resources for CSPNe and hot stellar winds (e.g. Pauldrach et al. 2004,
Kaschinski et al. 2012, 2013 together with the observational results of Tinkler & Lamers, 2002) will be implemented.
page 14
Evolution of Planetary Nebulae: analysis & numerical models
Since the variation of the stellar mass loss is significantly slower than the dynamical time scale resolved in the
numerical calculation, we expect no major problems for the numerical solution, since even the sudden onset of an
outflow shows no numerical instabilities (see Fig. 7).
With this model we will be in a position to study the 3D model of a PN covering the whole temporal evolution of the
PN phase, which to our knowledge was never done before. By introducing density disturbances in the otherwise
spherically symmetric wind outflow we will, additionally, be able to investigate the formation and evolution of
clumps using high resolution simulations.
As of this point the numerical models will be sufficiently detailed that observations and modelling can go hand in
hand: for the modelling we will get a major input from observation, but also the breakup of the fronts by instabilities
during the early phase of the HRD evolution will directly lead us to a range of possible parameters.
Using observation to determine the input parameters for our simulations, we will start modelling specific, individual
PNe and compare observables from our simulation results to corresponding observations. With this we should be in
a position to constrain the relevant physical processes in different PNe, where we will also address non-spherical
wind outflows.
As a further addition to the numerical model we will also investigate a multifluid model of the PN plasma, where the
neutral and the ionised phases of the gas will be treated individually. Due to the high modularity of the CRONOS
code adding such a feature will be comparatively easy. Here we intend to determine the changes to the results
brought about by such a more detailed modelling.
As the resolution of a large PN never will reach very small grid scales down to small scale clumps, the general used
“filling factor” of the radiative transfer is introduced nearly everywhere. We intend to study these local stability of
clumps by high resolution simulations (wind tunnel calculation of individual clump groups of a sub-domain like those
of Lim & Mellema 2003 and by us in Hunger et al. 2014). This will give us realistic input to the sub-grid physics of the
filling factor for the global PN calculations.
A special challenge certainly is the VLTP evolution. These objects have no Hydrogen and consist of up to 60% Carbon.
Thus first recombination fronts occurs already at temperatures above 50 000K. The collaboration, the PI is
embedded with A. Zijlstra and P.A.M. Hoof has collected many data and the PI has a Cycle 2 observational ALMA
project on that. But the theoretical modelling suffers from appropriate handling of the special properties of
recombination and opacity. A dedicated setup has to be built for that. Thus finally we will implement the hydrogen
poor radiative transfer into CLOUDY in collaboration with Peter van Hoof. This will especially have effects due to the
multiplicity of the recombination fronts of Carbon from C V to C IV, C III and finally C II. The carbon rich chemistry will
cause
a) completely different average atomic weight;
b) several recombination fronts in the range of gas temperatures of the outflow as it can already be seen in the C IV
and C III lines of our NTT spectra from 2003;
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Evolution of Planetary Nebulae: analysis & numerical models
c) the much higher absorption efficiency of the multi electron system compared to ionized Hydrogen will cause
higher accelerations and thus different mass loss rates.
For a sophisticated handling of the boundary condition of the born again nebula the input from the new calculations
of Herwig et al (2014) and from the large international collaboration for the ALMA project headed by the PI
(containing also the two major members of these theoretical working groups - Falk Herwig, Victoria, Canada and
Marco Pignatari, Basel, Switzerland) will be incooperated.
This sub-project will be carried out by the proposed PhD student and the Co-I. The link to the observational study
and the photoionization modelling will be done by the proposed post-Doc.
1.4 Work and time plan
We apply for a 3-year Post-Doc and a PhD position. Additionally, 1 master student should contribute to the data
reduction part in the observations planned within the project. The proposed staffing (including S. Kimeswenger) will
be, as the pilot study showed, sufficient to achieve our science goals for the proposed subprojects.
The PhD student will mainly on the CRONOS/CLOUDY numerical setup part together with the Co-I Ralf Kissmann
(subproject 1) while the Post-Doc will be in charge of the overall PN related topics and together with the PI on the
data analysis and interpretation of observations. (Post-Doc auch für Interpretation der Simulationen?!)
The specific work tasks during the three years are structured as follows:
1. Year:
Subproject 1: Connection of CLOUDY and HD model
We will start by computing CLOUDY tables for the cell-wise acceleration, cooling rate and absorbed radiation
intensity for an individual cell of the numerical simulations. This will be used in the implementation of the
ray-tracing procedure, where we consistently compute the cooling and radiative forcing within our radiationhydrodynamical model. Based on our previous modelling efforts we will investigate a first spherically
symmetric model with a steady wind outflow
2. Year
Subproject 1: Setup and Simulation of Evolutionary Models
Within our radiation-hydrodynamical models we will implement the evolutionary tracks for a generic CSPN.
The resulting fiducial PN model will be used to check for the stability of the code. Apart from that this model
will allow the first investigation of the full temporal evolution of a PN. Corresponding high-resolution
simulations will also allow to investigate the formation and evolution of clumps in such PNe.
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Evolution of Planetary Nebulae: analysis & numerical models
3. Year
Subproject 1: Simulation of individual objects and potential extensions
Building on the previous model we will investigate models of specific PNe. For this we will use data on the
plasma environment and the central star of the specific object as input to the simulations. With this, models
of individual objects will become possible and we will compare prediction for the observed structure of the
model PNe to actual observations. At this stage it will also be possible to investigate such special objects as,
e.g., born again nebulae.
We plan to publish at least two papers per subproject (observational: shock investigation of HST images early in
2015; overall nebulae analysis 2016/17; hydrodynamic modelling: Setup of PN evolutionary model combined with
the results of the preparation study late 2015; full model PN end of 2017). The project results will be published in
standard journals, unless the visibility of our work would significantly improve by taking a non-standard journal with
a high impact factor. For astronomical and astrophysical results Astronomy & Astrophysics (A&A) is the preferred
journal4. For the molecular research and the numerical methods AIP Advances will be appropriate5 . The project
results will also be presented at international conferences. (durch obiges ersetzen?)
1.5 Cooperation
1.5.1 Project related cooperation
 Albert Zijlstra6 Expertise: observation of AGN, post-AGB and PNe states of stars
University Manchester
 Peter van Hoof7 Expertise: CLOUDY co-developer
Royal Observatory of Belgium, Brussels
 Michael Probst, Expertise: quantum mechanical calculations of transitions in molecules
Institute for Ion and Applied Physics8, Innsbruck University
 Alexander Ostermann, Expertise: numerical analysis
Department of Mathematics, Innsbruck University
 Alexander Kendl, Expertise: plasma turbulence
Institute for Ion and Applied Physics9, Innsbruck University
 Thomas Fahringer, Expertise: parallel programming
the Institute of Computer Science, Innsbruck Universtiy
 Rolf Chini10, use of the Observatorio Cerro Armazones (OCA) Bochum & UCN facilities in Chile
Bochum University
1.5.2 Previous / other cooperations
 Horst Fichtner, Jens Kleimann, and Klaus Scherer (application of CRONOS tot he heliosphere)
Bochum University
4
http://www.aanda.org/
http://scitation.aip.org/content/aip/journal/adva
6
http://iapetus.phy.umist.ac.uk/
7
http://homepage.oma.be/pvh/
8
http://www.uibk.ac.at/ionen-angewandte-physik/
9
http://www.uibk.ac.at/ionen-angewandte-physik/
10
http://people.astro.ruhr-uni-bochum.de/chini/
5
page 17
Evolution of Planetary Nebulae: analysis & numerical models


Klaus Reitberger, Expertise: numerical simulation of colliding wind binaries
Institute for Astro- and Particle Physics, Innsbruck University
Anna Ogorzalek, Expertise: MHD simulation of colliding wind binaries
Institute for Astro- and Particle Physics, Innsbruck University
2. Human resources
2.1. Composition of the working groups


Group of applicant
o A Univ. Prof. Dr. Stefan Kimeswenger
o Dr. Stefan Noll (atmospheric research)
o Dr. Wolfgang Kausch (ESO instrumentation)
o Silvia Öttl, PhD (simulation and observation of PNe, FWF W1221)
o Amy Jones, MSc (atmospheric research, cand PhD, FWF P26130)
o Felix Niederwanger, MSc (numerical modelling of PNe)
o Mag. Stefanie Unterguggenberger (atmospheric research, FWF P26130)
o N.N. (recruitment running) one Post-Doc position (atmospheric research, Comité Mixto ESOGobierno de Chile)
Croup of Co-applicant
o Ass-Prof. Dr. Ralf Kissmann
o MSc Barbara Krebel (development of the CRONOS code, cand PhD, FWF I 1111-N27)
2.2.Remark: Affiliation of the applicant
Since September 2013, the applicant is associated with the Universidad Católica del Norte (UCN) in Antofagasta
(Chile) as a full professor. This second affiliation besides Innsbruck will give him privileged access to the observing
time reserved for Chilean institutions at the large astronomical observatories in this country and grants for
exclusively using the small facilities of the UCN at the OCA. Due to the related reduction of the teaching assignment,
he will be able to spend more time on research. The double affiliation status will be valid for the full duration of the
proposed project.
3. Potential additional aspects
The proposed project connects astronomical data with chemical investigations of molecules and especially the
investigation of the born-again stars that of the carbon enrichment and isotopy in the universe. The latter will be of
interest for various fields in (bio)-chemistry. The lifetime of molecular species in the harsh environment of the UV
radiation of PNe is of special interest for our colleagues from ion-physics.
page 18
Evolution of Planetary Nebulae: analysis & numerical models
4. Financial aspects
4.1. Information on the environment in the research institution
The group of the applicant is working on stellar astrophysics at late stages and on sky modelling for ESO
instrumentation. The applicant, Stefan Kimeswenger is, although full time paid researcher of the University of
Innsbruck about ¾ of time staying as full professor (profesor titular) at the Universidad Católica del Norte (UCN
Antofagasta/Chile). He will dedicate about 25% of his time purely for this research project, while a similar fraction
goes to the FWF project P26130 on atmospheric research with astronomical facilities11. The double affiliation with
UCN allows the unique access to Chilean observing time and exclusive access to the Cerro Armazones Observatory
facilities. The latter will allow narrow band imaging follow-up on demand and on short notice without any time
allocation committee involved.
The Co-applicant, Ralf Kissmann, has a tenure track position in the team of Olaf Reimer. His tenure to associate
professor is upcoming during 2015. He will focus on the supervision of the numerical/theoretical aspects in this
project and will spend about 10-15% of his time on this.
The working group of the applicant has its own dedicated cluster computer (> 200 cores and large 100 TB Network
Attached Storage (NAS) storage) and has access to larger facilities at the institute, and via the Austrian Centre of
Scientific Computing12 . Web resources to publicise the project and to make open access to the results as web
services13 are provided by the university. All workplaces are equipped with state of the art Sandy Bridge and Ivy
Bridge workstations with Gigabit network system and network printing facilities.
4.2. Information on the requested funding
4.2.1. Personnel costs (auch tabellarisch?!)
For the connection of the analysis of observations with theory, the connection to the molecular work and the
general link of the sections, Silvia Öttl (maiden name Dalnodar) is foreseen as a post-doctoral fellow (3 x 62 500 €).
The numerical modeling subproject (supported by the Co-applicant) will be the topic for a PhD fellow
(3 x 35 900 €). For this position Felix Niederwanger, currently finishing his MSc on the basic setup of these numerical
models is foreseen. Both contracts should last the whole time of the project.
For the extension of the homogeneous sample of CLOUDY studies on PNe we intend to attract MSc students to the
project. One only can give an educated guess – but it will be fairly likely to be able to enthuse up to 2 MSc students
in Innsbruck and 2 in Chile to get into the project. In case of UCN Antofagasta it also depends on the number of fee
waivers at the university (becas14) we can get from Comisión Nacional de Investigación Científica y Tecnológica
(CONICYT) for an MSc (Magíster en Ciencias Mención FísicaNegotiations are started already and a funding
application for the Comité Mixto ESO – Gobierno de Chile has been also submitted already (decision pending). ).
There is not yet installed a doctoral program in Physics at the UCN although an application with the PI included is in
preparation.
11
http://www.uibk.ac.at/eso/
http://acsc.uibk.ac.at/
13
http://www.uibk.ac.at/eso
14
http://www.conicyt.cl/becas-conicyt/
12
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Evolution of Planetary Nebulae: analysis & numerical models
For classification of data sets in the archives and basic work retrieving and preparing data, thus, two periods of 6
months each for an MSc student fellowship during the whole span of 3 years is applied for (16 850 €). This gives a
total of 312 050 € in personnel costs.
4.2.2. Equipment costs
The team has access to decent state of the art own and university owned facilities. Thus not applicable.
4.2.3. Travel costs
In addition to the typical travels to conferences covered, according to the FWF rules, by the general costs. As
consequence of his second position at the UCN, the applicant will spent a significant fraction of his time in
Antofagasta (Chile). In the case of absence, the group interaction will usually work by means of frequent video- and
teleconferences. However, for intensive joint research, this could be insufficient.
The nature of the team structure in the connection to the on demand observations at Cerro Armazones, covering
costs of observing runs applied for at Chilean Telescope Time Allocation Committee (CNTAC) and for the possibility
of larger periods of working together in face-to-face either in Innsbruck or in Antofagasta we apply for travel costs
(without local costs like board and lodging which will be provided by the applicant) between Europe and Chile.
The Post-Doc and the PhD student should visit for typically 2 weeks per year the two international partners
(Manchester & Brussels) and once during the project an incoming short visit of the partners on our budget is desired.
This gives a total of 23 100 € travel costs.
Tab. 2: overview of additional project specific travel costs
Meeting
attended by
cost estimate
SUM
per travel
per person
three stays at UCN (Antofagasta,
Co-Applicant /
travel: 1500 €
Chile) for 1 month each and / or two
Post-Doc / PhD
board + lodging: 900 €
PI
travel: 1500 €
12 000 €
Observing runs in Chile outside ESO
time (via CTAC)
Three out of schedule return trips of
applicant to Europe
One visit per year and person to
4 500 €
(no board and lodging)
Post-Doc / PhD
international partners (Manchester &
Travel: 500 €
board + lodging: 600 €
Brussels) for 2 weeks each
page 20
6 600 €
Evolution of Planetary Nebulae: analysis & numerical models
References:
Binette, L., Ferruit, P., Steffen, W., Raga, A. C. 2003, Rev. Mex. A&A, 39, 55
Blöcker, T. 1995, A&A, 299, 755
Boffetta, G., Ecke, R.E. 2012, Annu. Rev. Fluid Mechanics, 44, 427
Clayton, G.C., Bond, H.E., Long, L.A., et al. 2013, ApJ, 771, 130
Clayton, G.C., Kerber, F., Pirzkal, N., De Marco, O., Crowther, P.A., Fedrow, J.M., 2006, ApJ, 645, L69
Corradi, R. L. M., Schönberner, D., Steffen, M., Perinotto, M. 2000, A&A, 354, 1071
Corradi, R. L. M., Schönberner, D., Steffen, M., Perinotto, M. 2003, MNRAS, 340, 417
Corradi, R. L. M., Steffen, M., Schönberner, D., R. Jacob, R. 2007, A&A, 474, 529
Emprechtinger, M., Rauch, T., Kimeswenger, S. 2005, A&A, 431, 215
Emprechtinger, M., Forveille, T., Kimeswenger, S. 2004, A&A, 423, 1017
Ferland, G. J., Porter, R. L., van Hoof, P. A. M. 2013, Rev. Mex. Astron. Astrofis., 49, 137
Flaig, M., Kissmann, R., Kley, W. 2009, MNRAS, 394, 1887
Flaig, M., Kley, W., Kissmann, R. 2010, MNRAS, 409, 1297
Flaig, M., Ruoff, P., Kley, W., Kissmann, R. 2012, MNRAS, 420, 2419
García-Lario, P., Manchado, A., Riera, A., Mampaso, A., Pottasch, S. R. 1991, A&A, 249, 223
García-Segura, G., López, J. A., Steffen, W., Meaburn, J., Manchado, A., ApJ, 646, L61
Guerrero, M. A., Toalá, J. A., Medina, J. J., et al. 2013, A&A, 557, A121
Hajduk, M., Zijlstra, A. A., Herwig, F., van Hoof, P. A. M., Kerber, F., Kimeswenger, S., Pollacco, D. L., Evans, A., Lopéz,
J. A., Bryce, M., Eyres, S. P. S., Matsuura, M. 2005, Science, 308, 231
Hartigan, P. 2003, Rev. Mex. A&A Ser. Conf., 15, 112
Hartigan, P., Morse, J., Bally, J. 2000, AJ, 120, 1436
Herwig, F., Woodward, P.R., Lin, P.-H., Knox, M., 2014, ApJL submitted, (arxiv:2013.4584v2)
Hinkle, K.H., Joyce, R.R. 2014, ApJ, 785, 146
Huber, S., Dalnodar, S., Kausch, W., Kimeswenger, S., Probst, M., 2012, AIP Advances, 2, 032180
Hunger, L., Cosenza, B., Kimeswenger, S., Fahringer, T. 2014a, Random Fields generation on the GPU with the
Spectral Tuning Bands Method, in proceedings to Euro-Par2014, Porto.
Hunger, L., Kimeswenger, S., Kendl, A. 2014b, APN VI, Ed(s): C. Morisset, G. Delgado-Inglada & S. Torres-Peimbert.
Online at http://www.astroscu.unam.mx/apn6/PROCEEDINGS/, id. #117
Jones, D., Santander-Garcia, M., Boffin, H.M.J., Miszalski, B., Corradi, R.L.M., 2014, APN VI, Ed(s): C. Morisset, G.
Delgado-Inglada & S. Torres-Peimbert. Online at http://www.astroscu.unam.mx/apn6/PROCEEDINGS/, id. #43
Kaschinski, C.B., Pauldrach, A.W.W., Hoffmann, T.L, 2012, A&A, 542, A45
Kaschinski, C.B., Pauldrach, A.W.W., Hoffmann, T.L, 2013, A&A submitted, arxiv:1307.2948
Kifonidis, K. 1996, MSc Thesis, Gasdynamische Modelle für Planetarische Nebel mit sich schnell entwickelnden
Zentralsternen, TU Berlin & AIP Potsdam, supervisors: D. Schönberner & E. Sedlmayr.
page i
Evolution of Planetary Nebulae: analysis & numerical models
Kimeswenger, S., Zijlstra, A. A., van Hoof, P. A. M., et al. 2008, ASP Conf. Ser., 391, 177
Kissmann, R. 2014a, Habilitationsschrift (professorial dissertation / habilitation treatise) April 2014, University
Innsbruck: Turbulence and transport processes in astrophysical systems
Kissmann, R. 2014b, Astroparticle Physics, 55, 37
Kissmann, R., Flaig, M., Kley, W. 2011, 5th International Conference of Numerical Modeling of Space Plasma Flows
(ASTRONUM 2010), ASPC, 444, 36
Kissmann, R., Kleimann, J., Fichtner, H., Grauer, R. 2008, MNRAS, 391, 1577
Kissmann, R., Pomoell, J., Kley, W., 2009, J. Comp. Physics, 228, 2119
Kissmann, R., Pomoell, J., 2012, SIAM J. Scientific Computing, 34, A763
Kissmann, R., Werner, M., Egberts, K., Reimer, O., Csomós, P., Ostermann, A., 2012, AIPC, 1505, 450
Koller, J., Kimeswenger, S. 2001, ApJ, 559, 419
Koskela, A., Dalnodar, S., Kissmann, R., Reimer, A., Ostermann, A., Kimeswenger, S. 2012, IAUS, 283, 412
Kwok, S. 1982, ApJ, 258, 280
Kwok, S. 2007, The Origin and Evolution of Planetary Nebulae (Cambridge, UK), ISBN 9-780521039-07-9
Kwok, S., Purton, C.R., Fitzgerald, P.M. 1978, ApJ, 258, 280
Lechner, M.F.M., Kimeswenger, S. 2004, A&A, 411, L461
Lim, A.J., Mellema, G. 2003, A&A, 405, 189
Magrini, L., Perinotto, M., Corradi, R. L. M., Mampaso, A. 2003, A&A, 400, 511
Massey, P., Neugent, K.F., Hillier, D., Puls, J. 2013, ApJ, 768, 6
Matsuura, M., Speck, A. K., McHunu, B. M., et al. 2009, ApJ, 700, 1067
Matsuura, M., Speck, A. K., McHunu, B. M., et al. 2011, APN V, Ed(s): A. A. Zijlstra, F. Lykou, I. McDonald, and E.
Lagadec, Online at http://site.ebrary.com/lib/jodrell, P95
Niederwanger, F., 2014, MSc Thesis, CRONOS-Setup for Planetary Nebulae, University Innsbruck, supervisors: S.
Kimeswenger & R. Kissmann.
Niederwanger, F., Öttl, S., Kimeswenger, S., Kissmann, R., Reitberger, K. 2014, APN VI, , Ed(s): C. Morisset, G.
Delgado-Inglada and S. Torres-Peimbert. http://www.astroscu.unam.mx/apn6/PROCEEDINGS/ id. #67
Okorokov, V. A., Shustov, B. M., Tutukov, A. V., Yorke, H. W. 1985, A&A, 142, 441
Osterbrock, D. E., Ferland, G. J. 2006, Astrophysics of gaseous Nebulae and active Galactic Nuclei (University Science
Books, Sausalito, CA), ISBN 1-891389-34-3
Öttl, S., Huber, S.E., Kimeswenger, S., Probst, M. 2014a, APN VI, Ed(s): C. Morisset, G. Delgado-Inglada and S. TorresPeimbert. Online at http://www.astroscu.unam.mx/apn6/PROCEEDINGS/, id. #66
Öttl, S., Kimeswenger, S., Zijlstra, A.A. 2014b, A&A, 565, A87
Pauldrach, A.W.A., Hoffmann, T.L., Méndez, R.H. 2004, A&A, 419, 1111
Perinotto, M., Schönberner, D., Steffen, M., Calonaci, C. 2004, A&A, 414, 993
Pollacco, D. 1999, MNRAS, 304, 127
page ii
Evolution of Planetary Nebulae: analysis & numerical models
Proxauf, B., Öttl, S., Kimeswenger, S. 2014, A&A, 561, A10
Reitberger, K., Kissmann, R., Reimer, A., Reimer, O., Dubus, G. 2014, ApJ, 782, 96
Schönberner, D. 2008, ASP Conf. Ser., 391, 139
Schönberner, D., Steffen, M. 2002, RMxAC, 12, 144
Schönberner, D., Jacob, R., Lehmann, H., et al. 2014, Astronomische Nachrichten, 335, 378
Speck, A. K., Meixner, M., Jacoby, G. H., Knezek, P. M. 2003, PASP, 115, 170
Tabeling, P. 2002, Physics Reports, 362, 1
Tinkler, C. M., Lamers, H. J. G. L. M. 2002, A&A, 384, 987
van Hoof, P.A.M., Hajduk, M., Zijlstra, A. A., et al. 2007, A&A 471, L9
van Hoof, P.A.M., Kimeswenger, S., Zijlstra, A. A., et al. 2014, abstract to the 19th European White Dwarf Workshop,
August 11.-15. 2014, http://craq-astro.ca/eurowd14/seeabstract_en.php?id=66
Wiengarten, T., Kleimann, J., Fichtner, H., et al. 2013, Journal of Geophysical Research (Space Physics), 118, 29
Wisniewski, M., Kissmann, R., Spanier, F. 2013, Journal of Plasma Physics, 79, 597
Zijlstra, A.A. 2002, Astrophys. & Space Sci., 279, 171
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Evolution of Planetary Nebulae: analysis & numerical models
Acronyms:
1D / 2D / 3D
one, two and three dimensional
LCO
Las Campanas Observatory
CTIO
Cerro Tololo Inter-American Observatory
CNTAC
Chilean Telescope Time Allocation Committee (for LCO, CTIO and ESO LaSilla national telescopes)
CONICYT
Comisión Nacional de Investigación Científica y Tecnológica (Chilean Science Fund)
AGB
Asymptotic Giant Branch
ALMA
Atacama Large Millimeter/submillimeter Array
CSPN
central star of a planetary nebula
ESO
European Southern Observatory
FWF
Fonds zur Förderung der wissenschaftlichen Forschung (Austrian Science Fund)
HRD
Hertzsprung-Russell Diagram
HST
Hubble Space Telescope
ISM
Interstellar Matter
MHD
Magneto-HydroDynamic
MPI
Message Passing Interface
MSPN(e)
Multiple Shell Planetary Nebula (+ plural)
NAS
Network Attached Storage
(N)IR
(Near) Infrared
NTT
New Technology Telescope
OCA
Observatorio Cerro Armazones (Cerro Armazones Observatory – joint UCN + Bochum facility)
PDE(s)
Partial Differential Equation (+ plural)
PDR
Photon Dominated Region
PN(e)
Planetary Nebula (+ plural)
SAAO
South African Astronomical Observatory
SNRs
supernova remnants
TAC
Time Allocation Comittee
UCN
Universidad Católica del Norte in Antofagasta (Chile)
UV
Ultraviolet
VLT
Very Large Telescope
VLA
Very Large Array
VLTP
Very Late (Helium) Thermal Pulse
WD
White Dwarf
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Evolution of Planetary Nebulae: analysis & numerical models
During the study in The MSc thesis by F. Niederwanger, the gravitational field of the CSPN, an inner spherical
boundary (zone) in the wind forming region around the CSPN also providing smooth 1st and 2nd derivate of all
quantities (required to obtain stable conditions for the Riemann solvers were implemented.
Finally we are able to parameterize the inflow of a CSPN wind with a given density W, temperature TW and velocity
field vW. (Nach vorne oder sogar ganz raus (fände ich sehr okay))
For this purpose we will compute an extended table of resulting intensity, acceleration and heating values, by
applying CLOUDY to a plasma of constant temperature and density. From this we can deduce the effect of the stellar
irradiation on a single cell of our hydrodynamical model. Within our hydrodynamical simulations, we can then trace
Fig. 11: Outline of the iteration scheme proposed for the
radiative
transfer.
Static
photoionization
model
solutions from CLOUDY calculated for a wide range of
parameters will give feedback to CRONOS. It is not yet
finally decided, whether a full grid of CLOUDY setups
filling the whole parameter space will be calculated prior
to the runs (as used by Hunger et al. 2014b interpolating
between
data
points)
or
dynamic
self-learning
extensions of the grid by calling CLOUDY on the fly
during execution of CRONOS will be used (from
Niederwanger, 2014). (Die Abbildung kann Weg – neuer
Text, s.o.)
Thus these three quantities become time dependent.
????We will study the influence on the various Riemann solvers concerning the higher derivate due to the time
variations of the boundary conditions to avoid numerical fake shocks.
We will start the modelling with a spherically symmetric wind outflow, where we may later on try to model
asymmetrical CSPN outflows as well.
The handling of the outer boundary zone when recombination starts is certainly the most expensive part for the
code tests.?????
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Evolution of Planetary Nebulae: analysis & numerical models
The numerical stability of the solvers has to undergo various tests. Recombination of metals is important for the
cooling and heating of the plasma, and will therefore be properly calculated by CLOUDY. This, however, will mainly
be handled via the source terms f on the right-hand side of the PDEs. Apart from that, there is no significant
influence on the PDEs of the hydrodynamic model, as the mean atomic weight dominating the pressure tensor
changes only marginally. Only when Hydrogen undergoes a phase transition, will the PDEs be influenced. We get
steep spatial deviates in the terms on the left hand side of the equations above.)
To our knowledge, this kind of investigation was never done before for whole evolution along the PNe HRD.
The working group of the applicant, who is an associate professor at the Institute for Astro- and Particle Physics in
Innsbruck, currently consists of one post-doctoral fellow – namely Stefan Noll (FWF P26130 ‘Atmospheric Research
with large Astronomical Facilities’ - grant until end of 2016), and three PhD fellows, namely Amy Michelle Jones
(grant by the Austrian Ministry of Science and Investigation), and Mag. Stefanie Unterguggenberger (FWF P26130),
both working the atmospheric research, and Silvia Öttl (FWF W1221, doctoral school on interdisciplinary numerical
simulations DK-CIM) working on various aspects of simulations in planetary nebulae and molecular chemistry in
there. Additionally Wolfgang Kausch, working on ESO instrumentation topics is linked to the atmospheric research
group.
The applicant has published about 100 refereed articles in a wide field of astronomical research. He has developed
instruments and data reduction facilities for optical and infrared wavelengths. Heading the working group on the
ESO in-kind projects for the last 5 years, he has been involved in the radiative transfer sky modelling and extensive
data (re-)reduction ESO archive data. He is referee for the major European astrophysical journals and for about ten
years on projects of British, German, and Austrian science foundations.
Silvia Öttl (maiden name Dalnodar), who is proposed for the post-Doc position, is a young active scientist (4 refereed
articles, 8 proceedings, 2 book chapters), who successfully worked at different topics like molecules, observations,
and CLOUDY modelling of PNe. She has a background in astronomical spectroscopy and data analysis algorithms. She
joined team already for her BSc thesis in 2008. Since then, she has become an expert in all aspect of this research
field. The molecular work is strongly linked to the collaboration with the Ion Physics Department established by her.
The PhD on interdisciplinary modelling of aspects of PNe has been already submitted and the final defence exam is
expected for September 2014.
™
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Evolution of Planetary Nebulae: analysis & numerical models
Felix Niederwanger BSc defends in July 2014 his MSc thesis on adaption the CRONOS code for PNe. He is not only
physicist, but additionally an expert in computing and studied informatics (finishing his second master there soon).
We will benefit from a close collaboration with Albert Zijlstra15 (University Manchester and Director of the Jodrell
Bank Centre for Astrophysics). He is an expert in all kinds of observational aspects of AGB, post-AGB and PNe states
of the stars from optical to the radio wavelengths. Several joint publications during the last 10 years (including a
SCIENCE paper) show the success of this collaboration. The second close collaboration is established with Peter van
Hoof16 (Royal Observatory of Belgium, Brussels). Peter is an expert of CLOUDY, being a co-author of certain sections
of that code. He even is able to patch the code on demand (e.g. for a work 2005 we required extreme H poor
abundances which normally makes the code numerically unstable) (weg?!). Furthermore he is maintainer of the
atomic line lists used in the codes17. He is also member of the team in the joint publications mentioned above. He
agreed to provide help in all CLOUDY related topics.
We cooperate with the working group on Numerical Chemistry of Michael Probst in the Institute for Ion and Applied
Physics18, at Innsbruck university, for quantum mechanical calculations of transitions in molecules in PNe (Huber et
al. 2012; Öttl et al. 2014a). Both, the PI as well as the Co-I have well established collaborations on mathematical
problems for plasma physics theory with Alexander Ostermann heading the Numerical Analysis Group19 at the
Department of Mathematics (Koskela et al. 2012; Kissmann et al. 2012) and with Alexander Kendl of the working
group Complex Systems20 dealing mainly with plasma turbulence calculations (Hunger et al. 2014a). For
computational (technical) problems like parallel programming, we collaborate with (Vorname) Fahringer´s team at
the Distributed and Parallel Systems Group21 of the Institute of Informatics (Hunger et al 2014a). With Rolf Chini22 we
collaborate for the use of the Observatorio Cerro Armazones (OCA) Bochum & UCN facilities in Chile (the second
affiliation of the applicant). It will also reflect into this project, although mostly in using facilities and not in scientific
collaboration in this field of research itself.
The CoI Ralf Kissmann is involved in the supervision of the PhD thesis by Klaus Reitberger, who is investigating
colliding stellar winds of massive star binaries with the CRONOS code, where the numerical description of the stellar
wind is very similar to the case of a PN. Apart from that, he hired Barbara Krebl (FWF project I1111-N27) working on
15
http://iapetus.phy.umist.ac.uk/
http://homepage.oma.be/pvh/
17
http://www.pa.uky.edu/~peter/atomic/
18
http://www.uibk.ac.at/ionen-angewandte-physik/
19
https://numerical-analysis.uibk.ac.at/
20
http://www.uibk.ac.at/ionen-angewandte-physik/compsys/index.html.en
21
http://www.dps.uibk.ac.at/en/index.html
22
http://people.astro.ruhr-uni-bochum.de/chini/
16
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Evolution of Planetary Nebulae: analysis & numerical models
a PhD thesis on the implementation of logically rectangular grids into the CRONOS code. Thus, there is the possibility
for a close collaboration also on the PhD level.
page viii