From Technical University of Darmstadt [Technische Universität Darmstadt] (DE) via : “‘Europium stars’ in the dwarf galaxy Fornax lend new insight into the origin of the elements”

Technische Universität Darmstadt

From Technical University of Darmstadt [Technische Universität Darmstadt] (DE)


May 18, 2021

Credit: CC0 Public Domain

Europium is the key for understanding the formation of the heavy elements by the fast neutron capture process, the so-called r-process. Europium is a chemical element with the symbol Eu and atomic number 63.


This is crucial both for the formation of half of the elements heavier than iron and for the total abundance of thorium and uranium in the universe. The EUROPIUM group has combined theoretical astrophysical simulations with observations of the oldest stars in our Galaxy and in dwarf galaxies. The latter are small, dark-matter dominated galaxies orbiting our Galaxy. Dwarf galaxies are excellent test objects for studying the r-process, as some of the oldest metal-poor stars, those that have existed for 10 to 13 billion years, have exhibited an overabundance of r-process elements. Studies have even postulated that only a single neutron-rich event could be responsible for this enrichment in the smallest dwarf galaxies.

With their discovery, the researchers in Technical University of Darmstadt [Technische Universität Darmstadt] (DE) and Ruprecht Karl University of Heidelberg [Ruprecht-Karls-Universität Heidelberg](DE) have succeeded in determining the highest europium content ever observed—and they have created a new name for these stars: “europium stars”. These stars belong to the dwarf galaxy Fornax—a dwarf spheroidal galaxy with a high stellar content.

In their publication, the group also reports the first ever observation of lutetium in a dwarf galaxy and the largest sample of observed zirconium.

The “europium stars” in Fornax were born shortly after an explosive production of heavy elements. Based on the high stellar metal abundance, the extreme r-process event must have occurred as recently as four to five billion years ago. This is a very rare finding, as most europium-rich stars are much older. Therefore, europium stars provide insight into the origin of elements in the universe at a very specific and late time.

Heavy elements are formed by the r-process in the merger of two neutron stars or in the explosive end of massive stars with strong magnetic fields. The EUROPIUM group has analyzed these two high-energy events and performed detailed studies of element production in these environments. However, due to the still large uncertainties in the nuclear physics data, it is not possible to unambiguously assign the heavy elements in the “europium stars” to one of these astrophysical environments. Future experiments in the new accelerator center Facility for Antiproton and Ion Research: FAIR (DE) at the GSI Helmholtz Centre for Heavy Ion Research [GSI Helmholtzzentrum für Schwerionenforschung] (DE) in Darmstadt will significantly reduce these uncertainties.

In addition, the new Hessian cluster project ELEMENTS, in which Professor Arcones is a principal investigator, will uniquely combine simulations of neutron star fusion, nucleosynthesis calculations with the latest experimental information and observations to investigate the long-standing question: Where and how are heavy elements produced in the universe?

Science paper:
The Astrophysical Journal

See the full article here.


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Technical University of Darmstadt [Technische Universität Darmstadt] (DE) is a research university in the city of Darmstadt, Germany. It was founded in 1877 and received the right to award doctorates in 1899. In 1882, it was the first university in the world to set up a chair in electrical engineering. In 1883, the university founded the first faculty of electrical engineering and introduced the world’s first degree course in electrical engineering. In 2004, it became the first German university to be declared as an autonomous university. TU Darmstadt has assumed a pioneering role in Germany. Computer science, electrical engineering, artificial intelligence, mechatronics, business informatics, political science and many more courses were introduced as scientific disciplines in Germany by Darmstadt faculty.

TU Darmstadt founded the IT-Cluster Rhine-Main-Neckar, the “Silicon Valley of Germany”. The Johannes Gutenberg University Mainz, the Goethe University [Goethe-Universität] Frankfurt(DE) and the Technische Universität Darmstadt together form the Rhine-Main-Universities (RMU). TU Darmstadt is a member of TU9, a network of the most notable German Technische Universitäten (universities of technology) and of the Top Industrial Managers for Europe network, which allows for student exchanges between leading engineering schools.

According to the Förderatlas 2018 of the German Research Foundation, the university received the highest number of competitive grants in the field of computer science from the German Research Foundation. TU Darmstadt together with the German Research Center for Artificial Intelligence were selected as partner of the German “Federal Government’s Artificial Intelligence (AI) Strategy”. TU Darmstadt operates ATHENE, the largest research institute for cybersecurity in Europe.

Graduates of TU Darmstadt include Nobel Prize winners, entrepreneurs, managers, billionaires and politicians. As of September 2019, the university is associated with 4 Nobel laureates and 3 Wolf Prize in Physics laureates. For several years, TU Darmstadt has been one of the universities with the most top managers in the German economy. The university is currently among the top 3. The graduates include Oliver Zipse, Peter Grünberg, Chaim Weizmann and John Tu. Nobel laureate Albert Einstein recommended this university.

Since 2013, 95 companies have been founded in the vicinity of the university.

Research profile

TU Darmstadt defined six profile areas which characterize its research profile:

Thermo-fluids and interfaces
Future energy systems
From material to product innovation
Cybersecurity (CYSEC)
Internet and digitisation
Matter and radiation science


At TU Darmstadt there are several Sonderforschungsbereiche (SFB, collaborative research units) as well as several Graduiertenkollegs (graduate schools) that are funded by Deutsche Forschungsgemeinschaft. The university has attracted a considerable number of national and international research institutions to the Wissenschaftsstadt Darmstadt (Darmstadt – City of Science). Among them are:

GSI Helmholtz Centre for Heavy Ion Research (GSI)
Fraunhofer Institute for Secure Information Technology SIT
Fraunhofer Institute for Computer Graphics Research IGD
Fraunhofer Institute for Structural Durability and System Reliability
European Space Operations Centre (ESOC)
European Organisation for the Exploitation of Meteorological Satellite (EUMETSAT).

TU Darmstadt collaborates with these research institutes on a broad basis. For instance, TU Darmstadt and GSI agreed on a strategic partnership, which includes collaboration in the establishment of the FAIR Facility for Antiproton and Ion Research.

The European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU) has set up a research laboratory at TU Darmstadt, ESA_LAB@TU Darmstadt. It is the first research laboratory the European Space Agency has set up at a German university.

In 2018, TU Darmstadt has won the competition of the European Institute of Innovation and Technology (EIT) and is building an Institute for Manufacturing together with 50 partners including Siemens, Volkswagen, KUKA, German Research Center for Artificial Intelligence and Volvo. There will be an EIT Manufacturing Innovation Hub at the university.

TU Darmstadt is involved in the German Excellence Initiative. This initiative sponsored the Cluster of Excellence Smart Interfaces (2007–2014), the Graduate School of Computational Engineering and the Graduate School of Excellence Energy Science and Engineering. TU Darmstadt is also partially involved with the Cluster of Excellence Normative Orders, based at Goethe University Frankfurt.