Community Research and Development Information Service - CORDIS

FP7

SPACEINN Report Summary

Project ID: 312844
Funded under: FP7-SPACE
Country: Germany

Final Report Summary - SPACEINN (Exploitation of Space Data for Innovative Helio- and Asteroseismology)

Executive Summary:
Observations of oscillations on the solar and stellar surfaces have emerged as a unique and extremely powerful tool to gain information on, and understanding of, the processes in the Sun and stars, and the origin of the variability in the solar and stellar output. Through helio- and asteroseismology detailed inferences of the internal structure and rotation of the Sun, and extensive information on the properties of a broad range of stars can be obtained.
Space-based observations play a leading role in helio- and asteroseismology, in close synergy with ground-based observations as well as theoretical modelling. Long observing sequences are essential for measuring the oscillation frequencies with the precision required, and to extract the lowest mode frequencies involved. The enormous value of long-term space-based observations has been demonstrated in the solar case by the joint ESA/NASA SOHO mission (Solar and Heliospheric Observatory. This is now being followed by instruments on the NASA Solar Dynamics Observatory (SDO) mission. Large volumes of exquisite data on stellar oscillations of stars with a broad range of masses and ages are being collected by the CNES space mission CoRoT (Convection, Rotation and Transit) and the NASA Kepler mission.
Future space missions are under development, e.g. Solar Orbiter, to be launched by ESA in 2018, and TESS (Transiting Exoplanet Survey Satellite) to be launched by NASA in 2017.
Extensive Earth-based observations of solar oscillations have been undertaken with the GONG network (Global Oscillations Network Group) and the Birmingham Oscillation Network (BiSON) to ensure continuous monitoring. An asteroseismic network, SONG (Stellar Observations Network Group) is being established under Danish leadership.
Equally important for asteroseismology is the availability of supplementary data on the stars from more traditional observations, to determine their surface temperature, composition, radius, etc. Only through a coordinated use of the space- and ground-based data can the full potential of helio- and asteroseismology be realized.

Project Context and Objectives:
The NASA Kepler and K2 Missions and the French-led CoRoT satellite have realised huge breakthroughs for the study of stars, in particular those that show solar-like oscillations. Asteroseismic datasets of unprecedented length are now available on thousands of stars, including hundreds of cool main-sequence and sub-giant stars, and on thousands of red giants.
Furthermore the NASA space missions SoHO and SDO have delivered large volumes of high-quality data for helioseismology, i.e. probing the conditions and processes inside the Sun.
One of the main aims of SpaceInn is enhancing the effectiveness and productivity of the European scientific community, by promoting the use of space assets to build scientific and technological knowledge on helioseismology and asteroseismology. This has been achieved through mobilizing the best expertise, in particular academic researchers and scientists involved in the analysis and interpretation and presentation of space data, in the training, outreach and dissemination of the data and tools made available to support the scientific exploitation of existing space and ground data.
The work was structured and several work packages (WPs). Besides the administrational and scientific management in WP1 and WP2, the WPs 3-5 dealt with the technical development of the data base the “Seismic Plus Portal” and the creation of new tools for effectively exploiting data from space and from the ground. In addition WP6 was tasked with training, outreach and dissemination activities.

Considering the growing amount of helio- and asteroseismology data available from space missions (SOHO, CoRoT, Kepler, SDO,...) but also from ground-based observations (GONG, Bison, ground-based large programmes ...), the objective of WP3 was to promote the visibility and the use of these data within a large scientific community, providing:
• Coordinated access to the large variety of data sources available
• Tools to handle and combine data for a broad scientific community.
As described in Annex I to the Grant Agreement, this activity comprises the development or the upgrade of several data sources (WP3-2, WP3-3, WP3-4, WP3-5, WP3-6, see hereafter) and the development of a web portal “The Seismic Plus” (WP3-1, see hereafter) intended to be the well-identified place where the various existing data sources relevant for the Project are described and made accessible. This development work was planned to span over the whole 4 years program with different time scales adapted to the different data sources.

WP4 consisted of two workpackages: WP4.1 Global helioseismology and WP4.2 Local helioseismology. The main goal of WP4 is to develop advanced methods and tools for the analysis of helioseismology data from ground-based observatories and in space, as well as to make available and use numerical simulations to interpret the observations. Global methods developed under WP4.1 allow gaining insight into the general properties of the Sun, and provide therefore information for studies of the Sun as a star, i.e. synergies to asteroseismology emerge directly from this. Tools and models that provide localized information on the Sun, as developed under WP4.2 provide the possibility to better understand solar activity, therefore linking to Space Weather and the general study of magnetic activity on a star.

The CoRoT and Kepler missions implied a revolution in asteroseismology, particularly for stars with stochastically excited modes whose properties can be derived from scaling relations based on oscillation frequency patterns. For heat-driven oscillators, the frequencies do not necessarily follow such patterns and the identification of the modes is a necessary but difficult step prior to forward modelling, unless we can pinpoint the fundamental parameters of the stars with a high precision from additional independent data. This is why work package WP5 was devided into two sub-WPs. WP5.1 was focused on solar-like pulsators and WP5.2 on heat-driven pulsators.
The workplan under WP5.1 was to develop and verify robust methodologies to exploit, in a timely manner, the full scientific potential of this ensemble not only for testing stellar evolution theory, but also for providing accurate masses and ages for stellar populations and Galactic Archaeology studies.
The top-level objectives under WP5.1 were:
• To perform a detailed Hare-and-Hounds exercise, using artificial asteroseismic and complementary non-seismic data made from stellar evolutionary models to test estimation of fundamental stellar properties of stars by a variety of different codes and approaches;
• To use results of the Hare-and-Hounds exercise to inform the development of an automated analysis tool for providing accurate and precise estimates of fundamental stellar properties using asteroseismic (and non-seismic) data inputs and to make that tool widely available to the community;
• To develop and make available to the community tools for performing inversions of asteroseismic data to infer fundamental properties and internal structures of solar-like oscillators;
• To develop an analysis tool that calculates frequencies of interior structure models coupled to model atmospheres, allowing scientists to test the impact of those atmospheres on the observed oscillation frequencies;
• To produce catalogues of asteroseismic estimates of stellar properties and proxies of stellar activity.

Concerning WP5.2, one way to make extensive progress is to focus on stars for which fundamental stellar parameters can be deduced by other means than asteroseismology. Pulsating eclipsing binaries offer such an opportunity. Indeed, the masses and radii of stars in eclipsing binaries can be measured from combining light and radial velocity curves with a relative precision better than 1 %. If one of the stars is pulsating, then knowledge of its mass and radius allows the pulsational characteristics to be used to probe its internal structure with much better prospects than for single pulsators. This includes the tuning of physical processes such as diffusion, convective mixing and differential rotation. As for WP 5.2, the programme utilized the extensive expertise of the partner and affiliated institutes to:
• Develop new methodology to predict light and radial velocity curves of pulsating stars in eclipsing binaries simultaneously with the possibility to include spectroscopic information on temperatures and surface composition.
• Show that the theory of tidally induced oscillations needs extensive revision before it can be included in current state-of-the-art software tools.
• Compute extensive grids of models of subdwarf B stars and massive single main-sequence stars.
• Make new generation of 2D models for moderate to fast rotating stars publicly available.

The main objectives of the project in WP6 have been achieved through actions towards the dissemination of the results in the scientific community (publications and written reports, communications in a wide range of scientific meetings and workshops, and the publication of high impact articles for a wider audience). There was also a strong effort towards dissemination to the general public, through outreach and activities for schools, and also a very strong component of training of young researchers. Under this work-package the team has supported all activities on dissemination and ensured the proper monitoring of the effort to disseminate the results produced under all work-packages of the project.

Project Results:
The major achievement of SpaceInn was the creation of a dedicated virtual infrastructure for accessing ground- and space data for helioseismology and asteroseimology. This “Seismic Plus Portal” can be accessed now at:
http://voparis-spaceinn.obspm.fr/seismic-plus/

The development or upgrade of the various data sources corresponding to sub-workpackages WP3-2, WP3-3, WP3-4, WP3-5, WP3-6 and the development of the Seismic Plus Portal (WP3-1) have been completed during Period-3 (July 2015 – December 2016) following the initial plans and the results of the consultation led during Period-1 (SpaceInn/WP3-Meeting1: 21-22/10/2013 at Observatoire de Paris, http://www.spaceinn.eu/events/spaceinn-wp3- meeting-i/).
These various activities planned within WP3 have progressed following expectations during the third period of activity.
The WP3 activity has been presented in a talk (Michel et al. 2016) during the conference "Seismology of the Sun and the Distant Stars" held on 11-15 July 2016 in Angra do Heroísmo, Terceira-Açores, Portugal.

For helioseismology the work under WP4 consisted in creating a data base for inclusion into the Seismic Portal with continuously updated calibrated time series of the global helioseismic instruments as well as the surface magnetic proxy. We have also successfully compiled 3D simulations (HD and MHD) for the Sun and stars into this unique portal. Furthermore tatistical tools and methodologies were developed to properly combine contemporary solar datasets.
For local helioseismology new data analysis methods in form of the Fourier-Hankel analysis running on the SDO data center provides a complementary tool to investigate the solar subsurface layers.

The development of the tools for asteroseismology under WP5.1 may be summarized as follows:
• We performed a detailed Hare-and-Hounds exercise that involved scientists from 14 international institutes. Birmingham (the “Hares”) made the artificial data, which were designed to mimic the type and quality of data available from Kepler, K2 and CoRoT. Scientists at the other institutes (the “Hounds”) then applied their own “forward analysis” codes to infer the fundamental properties of the artificial stars. The exercise also tested the impact of having high-precision constraints on the stellar luminosities available from Gaia parallaxes. The results showed that it is possible to recover the stellar properties to levels of precision of around 1.5%, 4% and 20% in radius, mass and age respectively. Levels of precision are improved for stars that have masses closer to solar. There we confirmed that performance requirements, in terms of asteroseismic stellar properties estimation, can be met for the planned ESA PLATO Mission. At the same time we showed that more massive solar-type stars and atomic diffusion can present challenges for the analysis. We also tested extracting signatures of sharp features in the stellar interiors, specifically those due to ionization of helium in the outer layers and the base of the convective envelope. We found results from the forward modelling were on average more accurate than those from special, so-called “glitch fitting” analysis, where the latter approaches were sometimes subject to errors due to aliasing. Finally, we found that global as opposed to local optimisation algorithms provide more robust formal uncertainties on the estimated properties.
• We have developed and made available to the community a new software tool called Asteroseismic Inference on a Massive Scale (AIMS). The code has been designed for automated estimation of fundamental properties of large numbers of stars. The AIMS code applies a Markov-Chain Monte-Carlo (MCMC) algorithm to explore the posterior distribution of the sought-for properties, and uses asteroseismic and non-seismic constraints as input. In order to improve computational efficiency, it reads the global parameters and frequencies (calculated via a dedicated pulsation code) of a grid of models and interpolates these quantities as a function of grid parameters. The interpolation involves Delaunay triangulation, thereby allowing AIMS to work with unstructured grids of stellar evolutionary models.
• A new tool, called InversionPipeline, has been developed and made available to the international community. This new tool is capable of carrying out inversions of global stellar quantities using stellar evolutionary models from various grids. The classical constraints are used to select reference models from which to carry out inversions, and the asteroseismic data are used to target the appropriate theoretical frequencies for these inversions. A sophisticated GUI has been developed to help the user select specific inversion results as well as specific models, and this tool can also couple to outputs from AIMS. A new non-linear inversion tool for rotation profiles has also been developed. The purpose of this tool is to derive rotation profiles subject to supplementary constraints such as avoiding sign changes in the derived rotation profile, and/or imposing a negative gradient throughout the star.
• A new tool has been developed and made available to the international community to calculate solar-like oscillation frequencies for 3-D model atmospheres “patched” to 1-D stellar interiors models. Here, the challenge is to better understand the unwanted contamination (in the context of stellar properties estimation) of the mode frequencies due to the hard-to-model surface layers. A key innovation we have developed is the way equations to be solved are written by the user in the input file. The format is extremely flexible and intuitive and it is very easy for the user to modify and include additional physics (i.e. extra equations).
• We have provided asteroseismic catalogues of fundamental properties of solar-type stars observed by the NASA Kepler and K2 Missions. We have also provided a catalogue of activity proxies for solar-type stars observed by Kepler which have asteroseismic detections (some of the stars are also planet hosts).

The main results of WP5.2 can be summarized as follows:
PHOEBE2
PHOEBE2 is a python software package that allows simulating and fitting photometric and spectroscopic time series of single and multiple stars systems. For Deliverable 5.5, we have implemented extensions to include pulsations: simultaneous modelling of variability due to binary effects and pulsations of one or more components (for multiple star systems) is now possible.
Previously, the orbital effects and pulsations needed to be disentangled first, usually in an iterative way, but this approach did not always give satisfactory results, and can be problematic when pulsation amplitudes are large compared to binary effects in the light curves or when the time scales of both phenomena are similar. PHOEBE2 resolves those issues by including all effects simultaneously in a consistent way.
The code was released on 21/09/2016 with the accompanying paper Prsa et al. (2016, ApJSS, 227, id 29, 20pp). The PHOEBE2 code is publicly available from the website http://phoebe-project.org/.


GSSP
Deliverable 5.6 concerns radial-velocity measurements and fundamental parameter determination from spectral line fitting using high-resolution spectroscopy. For that purpose, A. Tkachenko (Post-Doc at KULeuven) developed a new code:
The Grid Search in Stellar Parameters (GSSP) software package is based on a grid search in the fundamental atmospheric parameters and (optionally) individual chemical abundances of the star (or binary stellar components) in question. We use the method of atmosphere models and spectrum synthesis, which assumes a comparison of the observations with each theoretical spectrum from the grid. For the calculation of synthetic spectra, we use the SynthV LTE-based radiative transfer code (Tsymbal 1996, ASPC, 108, 198) and a grid of atmosphere models pre-computed with the LLmodels code (Shulyak et al. 2004, A&A, 428, 993). Our grid of models covers large ranges in all fundamental atmospheric parameters and is freely distributed together with the software package itself.
We allow for optimization of five stellar parameters at a time: effective temperature, surface gravity, metallicity, microturbulent velocity, and projected rotational velocity of the star. The synthetic spectra can be computed in any number of wavelength ranges, and each considered spectral interval can be from a few angstroem up to a few thousands angstroem wide.
The grid of theoretical spectra is built from all possible combinations of the above-mentioned parameters. Each spectrum from the grid is compared to the observed spectrum of the star and the chi-square merit function is used to judge the goodness of fit. The code delivers the set of best-fit parameters, the corresponding synthetic spectrum, and the ASCII file containing the individual parameter values for all grid points and the corresponding chi-square values. We also account for possible global-scale imperfections in the normalization of the observed spectrum by means of a scaling factor that is computed from the least-squares fit of the synthetic spectrum to the observations and is applied to the latter. The value of the scaling factor is provided in the final chi-square table along with the other grid search parameters.
The GSSP package consists of three independent modules. The GSSP_single module treats the observed spectrum as the one of a single star. The GSSP_binary module has been specifically designed for fitting disentangled spectra of both binary components simultaneously. The GSSP_composite software module was designed for fitting composite spectra of double-lined spectroscopic binary systems.
Documentation and installation instruction for the GSSP code can be found at the following website: https://fys.kuleuven.be/ster/meetings/binary-2015/gssp-software-package

Tidally induced oscillations
For deliverable D5.7 we planned the inclusion of tidally excited oscillation modes in the computation of light and radial-velocity curves of close binaries. For this inclusion to be steered, case studies were searched for as guide of their photometric and spectroscopic behaviour. These case studies were observationally analysed and published as Schmid et al. (2015, A&A, 584, A35) and Tkachenko et al. (2016, MNRAS, 458, 1964-1976). Based on this deliverable the theory of tidal oscillations can be revised making use of the high-precision space photometry assembled with the Kepler satellite.

After interaction of some members of the developing team during the SpaceInn Symposium on the Azores (July 2016), the PHOEBE2 code was prepared for the inclusion of tidal oscillations. While first applications of seismic modelling of oscillations in close binary systems was achieved (Schmid & Aerts 2016, A&A, 592, A116), the PHOEBE2 code will be further developed to include more specific types of tidal oscillations in various types of binary pulsators in the future years to come, relying on the achievements implemented initially during SpaceInn.

New models of subdwarf B stars
The grid of evolutionary subdwarf B (sdB) star models was computed from the start of central He burning, taking into account atomic diffusion due to radiative levitation, gravitational settling, concentration diffusion, and thermal diffusion. We have computed the non-adiabatic pulsation properties of the models and studied the predicted p-mode and g-mode instability strips. The non-adiabatic pulsation properties of all the models in the grid can be downloaded on the following webpage: https://fys.kuleuven.be/ster/Projects/sdbgrid. The evolutionary tracks were computed using a code that is an adapted version of the STARS code (Eggleton 1971, MNRAS, 151, p. 351). The changes made to the code are described in Hu et al. (2008, A&A, 490, pp.243-252; 2009, A&A, 508, pp.869-876; 2010, A&A, 511, A87; 2011, MNRAS, 418, pp. 195-205). The pulsational properties are computed from the evolutionary models using MAD (Dupret et al. 2001, A&A, 366, p.166-173). For more information, see the accompanying paper Bloemen et al. (2014, A&A, 569, A123).

New models of massive single main-sequence stars
The second part of deliverable 5.8 concerns the calculation of new models for single main-sequence stars more massive than the sun. The work was led by E. Moravveji (KU Leuven) and V. Schmid (KU Leuven). Preliminary model grids tuned towards two specific B-type stars have been computed and made available to the community through the open-access papers Moravveji et al. (2015, A&A, 580, A27; 2016, ApJ, 823, id 130), along with their open websites. These papers laid the foundation for a more general grid of models of use to the community.
Stellar models were computed with the open-source stellar evolution code MESA (Paxton et al. 2011, ApJS, 192, id 3, 35pp.; 2013, ApJS, 208, id 4, 42pp.; 2015, ApJSS, 220, 15, 44pp.) from the zero-age main sequence up to the terminal-age main sequence. Chemical mixing is included via convective-core overshooting and diffusive mixing. Along the evolutionary tracks, adiabatic frequencies of gravity and pressure modes have been computed with GYRE (Townsend & Teitler, 2013, MNRAS, 435, 3406-3418). More information on the extent of the grid and the input physics can be found on this website: http://fys.kuleuven.be/ster/Software/grid-massive-stars. The grid is based on the one used by Schmid & Aerts (2016, A&A, 592, A116).

2D models for moderate to fast rotating stars
A new generation of stellar models in 2D, with inclusion of the effects of rotation, can now be computed thanks to the development and public delivery of the ESTER code. This theoretical and computational framework was developed in collaboration with Prof. Michel Rieutord from the group in Toulouse. The ESTER code is available for download and use by the community from the website http://www.ast.obs-mip.fr/users/rieutord/ESTER.html. As PHOEBE2, ESTER is an on-going project with plans for improvements in the future, in terms of evolutionary aspects of stars. Currently, ESTER is a static code that cannot deal with stellar evolution (as it was planned for SpaceInn).


The main result of WP6 was the monitoring of the dissemination efforts, measured through the following indicators:
Website (D6.1): Several lists with partners, human resources involved, events organized or relevant, publications and documents, datasets and support information, software and other tools with support information, outreach activities and materials, information of the project and its scientific topics, etc.
Support Documents (D6.2): Datasets (10), Software and Tools (20)
Articles and Short Reports (D6.3): Scientific Publications of High Impact (10), Books or Monographs (4+1), Scientific Papers (> 128), Scientific Communications as Oral Presentations or Posters (> 35), Outreach Actions and Media Coverage (> 24), Presentations of SPACEINN or display of its poster (> 20), Outreach talks (> 28).
Scientific Meetings (D6.4 & D6.5): Workshops/Tutorials organized (6), Relevant events for dissemination of the project results (> 7), Large project conference (1)


Potential Impact:
The main impact of SpaceInn results from the provision of data and data products from the Solar Heliospheric Observatory, the Solar Dynamics Observatory, CoRoT and Kepler in combination with ground-based data from GONG, BiSON, MARK-I and follow-up observations of stars, respectively. This is the basis to broaden the international usuage of the data and generating synergies. The helio- and asteroseismology is now able to establish fruitful connections with other related communities and disciplines, especially with the space weather community, exo-planetology community, and research groups working on the evolution of the galaxy.
For the helio- and asteroseismology research area in Europe effectiveness and productivity of this majore European scientific community is enhanced, by now promoting the use of space assets to build the scientific and technological knowledge.
The statistics of the Seismic Plus Portal giving access to the various data sources mentioned in the project, including those specificaly developed within the project are followed regularly. The numbers for 2016 are given in the attachements, showing a good frequentation for this first period (see attached figure for mensual statistics).
The main impacts and exploitation are relevant to the international asteroseismology community, the wider stellar astrophysics community, the exoplanet community, and the Galactic astrophysics community. There is also the wider societal impact arising from engagement with the general public as part of the associated outreach activities.
• The tasks completed in the helioseismology work package will have a strong impact in the solar and stellar community far beyond seismology. Now the GOLF and VIRGO calibrated time series are available and they will be continuously updated as the SoHO mission will continue. We have also proven the ability of the photospheric magnetic proxy to monitor surface magnetic modulations and we also provide it for the Sun. This will allow the community to use the data taken by the present and future astero-seismic space missions to study surface magnetic fields and their evolution. The different tools for global and local helioseismology we have developed in our working group are being used by many scientists across Europe. They are being especially useful for students starting in our discipline, but also extend the state-of-the-art of helioseismology. Finally, the compilation of the existing 3D solar and stellar simulations into a single portal is of great value for the solar and stellar community and we expect that it will be largely used by the community in the incoming years.
• The asteroseismology community has benefited directly via developments in the state-of-the-art of stellar properties estimation using asteroseismic data. There are the tools that have been developed and made available to the international community, which will allow them to exploit the exquisite data from Kepler, K2 and CoRoT in a timely manner. The work is also helping to inform members of the international community in development of their own codes, and which techniques are best suited to different combinations and quality of input data.
• The stellar astrophysics community will benefit from the developments in methodology and the tools that have been made available, since the outputs play an integral part in studies of stellar structure and evolution.
• Exploiting data for massive heat-driven pulsators to gain insight in the physical processes at hand and to improve stellar models is a tedious task that can take months per target. We have developed tools that are publicly and freely available to interpret this kind of data to the high precision available. They allow combining different types of data, from space photometry to high-resolution ground-based spectroscopy. Furthermore, we provide model grids for subdwarf B stars and massive main-sequence stars. This breaks down the barrier to spend precious resources on mastering intricate stellar modelling codes, which are often not open-source.
• The exoplanet community will benefit, because the work and outputs have developed the state-of-the-art and provided new, more robust tools for stellar properties estimation which plays a key role in the characterisation and study of newly discovered exoplanet systems: constraining the properties of the discovered planets, and the evolution of the architectures of exoplanet systems, rely on having accurate and precise properties for the host stars.
• The Galactic Archaeology and stellar population communities will benefit, benefit, because the work and outputs have developed the state-of-the-art and provided new, more robust tools for stellar properties estimation, most crucially ages. Studies of the structure and evolution of the Galaxy have previously been hampered by a lack of well-constrained estimates on individual masses and ages for large numbers of stars. Asteroseismology can now provide those estimates, but the asteroseismic analysis must be tested and shown by be robust: our work has made significant advances in testing and developing those methods.

Through the main actions of WP6 is has been possible to reach a wide scientific community, with a strong dissemination of the results. This was done both as documents/publications and presentations and cover the community working on topics of the project and several other groups that can benefit from the results of the project. In this way the outcome of the project has been able to build a long-term impact far beyond the teams involved in the project. The large range of publications is also the backbone of that long-term impact as these provide the record that will allow new communities to explore the data and tools provided by the project.
As part of the dissemination measures implemented, the project has provided advanced training to a new generation of researchers that have become the main users of the tools and datasets produced by the project. This group of young researchers (mostly MSc, PhD and young Postdoc researchers) are the community that will secure the continued usage of the results of the project and can provide the support to continue the development of new developments of the tools and expansion of the applications.
Through the actions for the general public, the project has also secured a stronger public perception of the topics covered by the project and built a wider range of activities and presentations that have been and will continue to be used to communicate with the public using a diversified range of outreach activities. Over the past four years, outreach activities have included talks to the public, at schools, and to societies; as well as engaging the public via outputs from collaboration with artists (e.g., Birmingham’s work with a sound artist).

List of Websites:
http://www.spaceinn.eu

Contact details:
SpaceInn Project
Markus Roth
Kiepenheuer-Institut für Sonnenphysik
Schöneckstr. 6
79104 Freiburg
Germany

Tel.: +49-761-3198-0
e-mail: mroth@leibniz-kis.de

Related information

Reported by

KIEPENHEUER-INSTITUT FUER SONNENPHYSIK
Germany
Follow us on: RSS Facebook Twitter YouTube Managed by the EU Publications Office Top