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Uncovering the birthplaces of stars in the Milky Way

Using precise stellar age and iron content measurements, the stellar birth places could be recovered. Credit: I. Minchev (AIP)

Uncovering the birthplaces of stars in the Milky Way

13 September 2018. An international team of scientists led by Ivan Minchev of the Leibniz Institute for Astrophysics Potsdam (AIP) has found a way to recover the birth places of stars in our Galaxy...

Stars in galactic discs have long been known to wander away from their birth sites owing to a phenomenon known as “radial migration”. This movement across the Galaxy severely hampers inferences of the Milky Way formation history. Radial migration is influenced by a number of parameters that are still poorly known: for example, the size and speed of the Galactic bar, the number and shape of spiral arms in the Galactic disc, and the frequency of smaller galaxies colliding with the Milky Way during the past 10 billion years and their respective masses.

To circumvent these obstacles, the scientists devised a way of recovering the Galactic migration history using the ages and chemical composition of stars as “Archaeological artifacts”. They used the well-established fact that star formation in the Galactic disc progresses gradually outwards, following that stars born at a given position at a particular time have a distinct chemical-abundance pattern. Therefore, if the age and chemical composition (its iron content, for example) of a star can be measured very precisely, it becomes possible to directly infer its birth position in the Galactic disc without additional modeling assumptions.

The team used a sample of about 600 solar-neighborhood stars observed with the high-resolution spectrograph HARPS mounted on the 3.6 m telescope of ESO’s La Silla Observatory in Chile. Thanks to the very precise age and iron abundance measurements, it was found that these stars were born all across the Galactic disc, with older ones coming more from the central parts.

Researches can now use this method for calculation of birth places even for stars not in the original sample. For example, given the age of our Sun of 4.6 billion years and its iron content, it could be estimated that the Sun was born about 2,000 light years closer to the Galactic center than it is currently located.

Minchev comments: “Once in the possession of birth radii, a wealth of invaluable information could be gained about the Milky Way past, even from this small number of stars with precise enough measurements available to us at this time.” Co-author Friedrich Anders adds: “In the near future, applying this method to the extremely high-quality data from the Gaia mission and ground-based spectroscopic surveys will allow much more exact measurements of the migration history and, thus, the Milky Way past.”

 


Left: A sample of about 600 stars situated very close to the Sun was used (approximate volume shown by arrow). Right: Using precise stellar age and iron content measurements, the stellar birth places could be recovered. Older stars were found to arrive preferentially from the inner parts of the disk (lighter coloured dots), while younger ones (darker coluored dots) were born closer to their current distance from the Galactic centre. The background image shows a simulation of a galaxy similar to the Milky Way for perspective. Credit: I. Minchev (AIP)


Scientific Contact

Ivan Minchev, 0331-7499-259, iminchev@aip.de

Media contact

Franziska Gräfe, 0331-7499 803, presse@aip.de

Publication

http://doi.org/10.1093/mnras/sty2033

 

The key areas of research at the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. The AIP has been a member of the Leibniz Association since 1992.

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In memoriam of Prof. Hans Oleak

On September 7, 2018, Prof. Hans Oleak passed away at the age of 88. The Leibniz Institute for Astrophysics Potsdam (AIP) mourns the loss of our esteemed colleague, who throughout his life shared h...

Hans Oleak studied physics with a focus on astrophysics at the Friedrich Schiller University Jena. In 1956 he started his scientific work at the Babelsberg Observatory in Potsdam. After graduating in the field of cosmology, he was appointed professor by the Academy of Sciences in 1981. He was head of department for the field of extragalactic research at the AIP and taught at the University of Potsdam, the Humboldt University and at the Technical University of Berlin. The astrophysicist was one of the co-founders of the European Astronomical Society in 1990 and one of the first members of the newly founded Urania Association in Potsdam in 1991.

 

Hans Oleak always shared his enthusiasm for astronomy with great dedication and it was important to him to pass on his knowledge in a comprehensible way. So he held numerous popular science lectures, organized teacher training and was the chief editor of the astronomical magazine "The Stars" from 1993 to 1996. In addition, he was involved as a board member and chairman of the URANIA Association Potsdam. He also shared his knowledge in books and television programs. In 2013, the City of Potsdam honored him for his commitment with the honorary office award. In March 2018 he received the Wilhelm Foerster Prize from Urania Potsdam.

Our condolences are to his relatives, his family, friends and all who were close to him.

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15. AIP-Thinkshop: The role of feedback in galaxy formation

The active galaxy M82. Supernova explosions through gas and dust (blue and red) from the galaxy (yellow-green) into space. Credit: NASA, ESA, CXC, and JPL-Caltech

15. AIP-Thinkshop: The role of feedback in galaxy formation

From the 3rd to the 7th of September, more than 130 scientists meet at the 15th Potsdamer Thinkshop on the Telegrafenberg, Potsdam, Germany.

Each year, the event series of the Leibniz Institute for Astrophysics Potsdam (AIP) focuses on a different field of astrophysical research. This year, it's about the processes that influence the formation of galaxies.

"The 15th Thinkshop brings leading international experts and students working in both Galactic and extragalactic astronomy together. They will discuss the different components of a galaxy - stars, gas, non-thermal components, dust, and dark matter -  and where these components are found within and around galaxies, from both an observational and a theoretical point of view. The final objective is getting a better understanding on the feedback processes that rule the evolution of galaxies," explains Prof. Dr. Christoph Pfrommer, head of the Cosmology and High-Energy Astrophysics section. More information on this event is available at the conference website https://thinkshop.aip.de/15/.

 

Scientific contact:

Prof. Dr. Christoph Pfrommer, 0331-7499 513, cpfrommer@aip.de


Media contact:

Franziska Gräfe, 0331-7499 803, presse@aip.de

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Else Starkenburg receives Biermann Award from the Astronomical Society

The award winner of the Ludwig Biermann Award of the German Astronomical Society, Dr. Else Starkenburg. (Credit: AIP)

Else Starkenburg receives Biermann Award from the Astronomical Society

22nd August 2018. With the Ludwig Biermann Award, the Astronomical Society is honoring Dr. Else Starkenburg from the Leibniz Institute for Astrophysics Potsdam (AIP) for her scientific work on the ...

"In her still young research career, Dr. Starkenburg is firmly established internationally as a recognized scientist in her field of research, Galactic Archeology," says Prof. Dr. Joachim Wambsganß, President of the Astronomical Society. "This manifests itself in her numerous and often cited publications, but also in frequent invited lectures – including five reviews at international conferences."

It is not the first science award for Starkenburg: in 2016, her work was awarded with the Academy Prize for Physics from the Academy of Sciences in Göttingen. After her graduation and subsequent doctorate in Groningen, the Netherlands, she worked as a post-doctoral fellow at the University of Victoria in Canada. In 2014, she moved to Potsdam for the Karl Schwarzschild Fellowship, with which the AIP promotes promising researchers over a period of three to five years to conduct independent research. Shortly thereafter, Else Starkenburg also raised funds for an Emmy Noether research group from the DFG.

 

Her research focuses Milky Way Archeology: her goal is to reconstruct the origin and early stages of evolution of our Milky Way and neighbouring galaxies. For this purpose, the Starkenburg studies stellar populations with regard to their chemical compositions. She co-initiated the PRISTINE Survey, an international collaboration dedicated to the search for particularly metal-poor – and therefore very old – stars.

The German Astronomical Society (Astronomische Gesellschaft, or AG for short) is the professional German national association for astronomy and astrophysics. The AG promotes activities in science and research, strengthens exchange between its members and supports the dissemination of science to the public and in education. Since 1989, the Astronomical Society has honoured outstanding junior researchers with the Ludwig Biermann Award.

 

Media contact

Franziska Gräfe, 0331-7499 803, presse@aip.de

 

The key areas of research at the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. The AIP has been a member of the Leibniz Association since 1992.

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Sun under double observation

Parker Solar Probe. (Credit: NASA)

Sun under double observation

13th August 2018. NASA's Parker Solar Probe, launched on 12th August, will be the first spacecraft to approach the sun reaching 10 solar radii, and will provide science with new insights into our h...

What effect does solar activity have on the immediate surrounding space - and ultimately also on our earth? The space mission Parker Solar Probe will provide answers to these and other questions. They are of fundamental societal interest, as solar activity has a huge impact on our technological capabilities: it may cause interference with GPS navigation and electronic components in airplanes, satellites and hospitals.

With the space satellite, scientists want to examine the outer layer of the solar atmosphere - the corona - and the near-solar interplanetary space. One of them is Prof. Dr. Gottfried Mann. At the AIP he heads the department "Physics of the Sun" and researches, among other things, the sun and space weather. Together with 20 other international scientists, he has secured simultaneous observation time with LOFAR and Parker Solar Probe– a total of 1,024 hours over the next two years. The observation times are deliberately chosen: In the so-called perihelion phases, when the satellite comes closest to the sun, the research group plans simultaneous observations with the earthbound radio telescope LOFAR. "With these ground-based supplementary measurements, LOFAR will provide important data. This will make it possible in unprecedented ways to explore solar activity and its spread from the corona into the interplanetary space," Mann explains.

The International LOFAR Telescope (ILT) is a European joint project under Dutch management with numerous stations in Northern and Western Europe. In the last two years, the ILT has been extended by three stations in Poland and one station in Ireland. Thus, the base length increased to 1,885 km in east-west direction. In north-south direction, the base length is 1,301 km from Onsala in Sweden to Nançay in France. At present, the ILT consists of a central core of 24 stations and 14 further individual stations distributed in the Netherlands as well as an additional 13 international stations in Europe. The AIP participates in LOFAR with its own station in Potsdam-Bornim.

The scientific evaluation of the LOFAR data is organized in the form of six key science projects. One of them, Solar Physics and Space Weather with LOFAR, is managed by the AIP. With its high sensitivity and flexibility LOFAR is a suitable tool for a variety of scientific topics - from the early universe to near-Earth space.

 

LOFAR-Station in Potsdam-Bornim. (Credit: AIP)


Scientific contact at AIP

apl. Prof. Dr. Gottfried Mann, 0331-7499-292, gmann@aip.de

Media contact

Franziska Gräfe, 0331-7499 803, presse@aip.de

Further Information

LOFAR                         https://bit.ly/2AVchS4

Parker Solar Probe       http://parkersolarprobe.jhuapl.edu

Press release NASA      https://go.nasa.gov/2vCYbzO

 

The key areas of research at the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. The AIP has been a member of the Leibniz Association since 1992.

Read more ...