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  • richardmitnick 10:11 pm on February 15, 2019 Permalink | Reply
    Tags: "Tidal Tails – The Beginning Of The End Of An Open Star Cluster", , , , , , The Hyades- the star cluster closest to the Sun, University of Heidelberg   

    From University of Heidelberg: “Tidal Tails – The Beginning Of The End Of An Open Star Cluster” 

    U Heidelberg bloc

    From University of Heidelberg

    15 February 2019

    Heidelberg researchers verify this phenomenon using Gaia data from the Hyades.

    ESA/GAIA satellite

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    Image of the Hyades, the star cluster closest to the Sun. Source: NASA, ESA, and STScI

    NASA/ESA Hubble Telescope

    In the course of their life, open star clusters continuously lose stars to their surroundings. The resulting swath of tidal tails provides a glimpse into the evolution and dissolution of a star cluster. Thus far only tidal tails of massive globular clusters and dwarf galaxies have been discovered in the Milky Way system. In open clusters, this phenomenon existed only in theory. Researchers at Heidelberg University have now finally verified the existence of such a tidal tail in the star cluster closest to the Sun, the Hyades. An analysis of measurements from the Gaia satellite led to the discovery.

    Open star clusters are collections of approximately 100 to a few thousand stars that emerge almost simultaneously from a collapsing gas cloud and move through space at about the same speed. Owing to a number of influences, however, they do begin to disperse after a few hundred million years. Among the factors working against the gravitationally bound stars is the tidal force of a galaxy, which pulls the stars out of the cluster. Tidal tails then form during the movement of the star cluster through the Milky Way. It is the beginning of the end of an open star cluster.

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    Position of the Hyades and its now observed tidal tails in the sky. The background shows Gaia’s all-sky view of our Milky Way Galaxy. Source: S. Röser, ESA/Gaia/DPAC

    Together with researchers from the Max Planck Institute for Astronomy in Heidelberg, scientists from the Centre for Astronomy of Heidelberg University (ZAH) have detected this phenomenon for the first time in the Hyades, one of the older and best-studied open star clusters in the Milky Way system. They studied the data published in April 2018 from the Gaia satellite, which has been systematically mapping the heavens for five years. Rather than taking direct photographs, Gaia measures the stars’ motion and position.

    From this data, the Heidelberg astronomers identified two tidal tails of the Hyades with a total of approximately 500 stars extending up to 650 light-years from the cluster. Dr Siegfried Röser of the Königstuhl State Observatory of the ZAH explains that one of the tails precedes the open star cluster and the other follows it. “Our discovery shows that it is possible to trace the trajectories of individual stars of the Milky Way back to their point of origin in a star cluster”, states Dr Röser. The astronomer believes that this marks the beginning of many significant discoveries in galactic astronomy. Apart from the Heidelberg astronomers, a team of researchers from Vienna also discovered the tidal tails of the Hyades.

    The research was conducted under the auspices of The Milky Way System Collaborative Research Centre (CRC 881) at Heidelberg University, which is funded by the German Research Foundation.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Heidelberg Campus

    Founded in 1386, Heidelberg University, a state university of BadenWürttemberg, is Germany’s oldest university. In continuing its timehonoured tradition as a research university of international standing the Ruprecht-Karls-University’s mission is guided by the following principles:
    Firmly rooted in its history, the University is committed to expanding and disseminating our knowledge about all aspects of humanity and nature through research and education. The University upholds the principle of freedom of research and education, acknowledging its responsibility to humanity, society, and nature.

     
  • richardmitnick 9:34 am on April 21, 2018 Permalink | Reply
    Tags: , , , , , , University of Heidelberg   

    From University of Heidelberg: “Stars Are Born in Loose Groupings” 

    U Heidelberg bloc

    University of Heidelberg

    20 April 2018

    Analysis of Gaia satellite data points to a new view of star formation.

    ESA/GAIA satellite

    Based on previously published data from the Gaia Mission, researchers at Heidelberg University have derived the conditions under which stars form. The Gaia satellite is measuring the three-dimensional positions and motions of stars in the Milky Way with unprecedented accuracy.

    Milky Way Galaxy Credits: NASA/JPL-Caltech/R. Hurt

    Milky Way by GAIA ESA

    Using these data, Dr Jacob Ward and Dr Diederik Kruijssen determined the positions, distances and speeds of a large number of young massive stars within 18 nearby loose stellar groupings. The researchers were able to demonstrate that there is no evidence whatsoever that these associations are expanding. They therefore could not have originated as a dense cluster and then expanded to their current size.

    The long-standing model of star formation maintains that most, if not all stars originate in relatively densely packed star clusters. Experts refer to this as the “monolithic” model of star formation. Based on that model, every grouping of young stars observable today must have had its origin in one or more much denser clusters. After the stars formed, these clusters expelled the remaining molecular gas and were able to expand due to the loss of the gravitationally bound mass. Today’s less dense clusters would have formed in this way and hence now, millions of years later, would evidence clear signs of strong expansion.

    For Dr Ward and Dr Kruijssen, the results of their research clearly indicate that the “monolithic” model of star formation is simply not viable. Both researchers favour another explanation, namely that only a small fraction of stars are born within dense clusters. Instead, stars form across wide-spread molecular gas clouds across a broad range of densities. This “hierarchical” model of star formation explains today’s star clusters and associations with a variety of densities showing no signs of further expansion.

    The next publication of data from the Gaia Mission is scheduled for April 25 this year. By then, data on over a billion stars will have been collected – at least five hundred times that of the two million stars that were included in this initial study. Jacob Ward and Diederik Kruijssen hope that this new data will enable them to expand their study to potentially hundreds of loose stellar groupings, known as OB Associations, and to delve much further into the question of how stars originate. Dr Ward and Dr Kruijssen conduct research at the Institute of Astronomical Computing at Heidelberg University’s Centre for Astronomy (ZAH). Their research is part of the work being done in the Collaborative Research Center (CRC 881) “The Milky Way System”.

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    Hubble Space Telescope image of the OB association Cepheus OB4, one of the loose groupings of young stars studied by Dr Ward and Dr Kruijssen. The young stars are visible in bright blue; the gas and dust left after their formation is shown in red colours and dark shades. The results of the Gaia satellite show that Cepheus OB4 undergo no expansion, indicating that the stars formed in their current spatial configuration.
    Source: Davide De Martin & the ESA/ESO/NASA Photoshop FITS Liberator.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    U Heidelberg Campus

    Founded in 1386, Heidelberg University, a state university of BadenWürttemberg, is Germany’s oldest university. In continuing its timehonoured tradition as a research university of international standing the Ruprecht-Karls-University’s mission is guided by the following principles:
    Firmly rooted in its history, the University is committed to expanding and disseminating our knowledge about all aspects of humanity and nature through research and education. The University upholds the principle of freedom of research and education, acknowledging its responsibility to humanity, society, and nature.

     
  • richardmitnick 11:24 am on March 8, 2017 Permalink | Reply
    Tags: , , , Leibniz Institute for Astrophysics Potsdam, micro-optic systems used in telecommunications suitable for use in large telescopes, New Technologies for Astronomical Research, University of Cologne, University of Heidelberg   

    From University of Heidelberg: “New Technologies for Astronomical Research” 

    U Heidelberg bloc

    University of Heidelberg

    8 March 2017
    Prof. Dr Andreas Quirrenbach
    Centre for Astronomy of Heidelberg University – Königstuhl State Observatory
    Phone +49 6221 54-1792
    a.quirrenbach@lsw.uni-heidelberg.de

    Dr Robert Harris, Centre for Astronomy of Heidelberg University – Königstuhl State Observatory
    Phone +49 6221 54-1733
    r.harris@lsw.uni-heidelberg.de

    Prof. Dr Lucas Labadie
    University of Cologne
    Institute of Physics I
    Phone +49 221 470-3493
    labadie@ph1.uni-koeln.de

    Dr Stefano Minardi
    Leibniz Institute for Astrophysics Potsdam
    Phone +49 331 7499-687
    sminardi@aip.de

    Dr Roger Haynes
    Leibniz Institute for Astrophysics Potsdam
    Phone +49 331 7499-654
    rhaynes@aip.de

    Communications and Marketing
    Press Office
    Phone +49 6221 54-2311
    presse@rektorat.uni-heidelberg.de

    DFG supports development of micro-optical systems for use in astronomical instruments

    1
    Photonic component for an astronomical interferometer. Photo: University of Cologne, University of Jena and Leibniz Institute for Astrophysics Potsdam

    Three working groups from Heidelberg, Cologne and Potsdam are involved in a joint project to develop a new technology for astronomical research. The researchers intend to render micro-optic systems used in telecommunications suitable for use in large telescopes. The collaborative project is being supported by the Königstuhl State Observatory of the Centre for Astronomy of Heidelberg University, the Institute of Physics I of the University of Cologne, and the Leibniz Institute for Astrophysics in Potsdam. The German Research Foundation (DFG) has approved funding of approx. 1.1 million euros for the three-year project, which recently started work.

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    Operating principle of a photonic reformer. In this example, a squared field of view is converted into a thin line, which can be very effectively coupled into an astronomical spectrograph. Image: Dr Robert Harris, Königstuhl State Observatory, Centre for Astronomy of Heidelberg University

    The “Novel Astronomical Instrumentation through Photonic Reformatting” (NAIR) project is being funded by the DFG within the “New Instrumentation for Research” call for proposals. The researchers in Heidelberg, Cologne and Potsdam will design and test components that can efficiently rearrange the light of stars and galaxies to enable high-precision measurements of cosmic objects. This new technology is targeted for use on large telescopes in order to, for example, search for earth-like planets of nearby stars and determine their atmospheric composition.

    “When building spectrographs for modern telescopes, we increasingly encounter technical and financial limitations,” explains Prof. Dr Andreas Quirrenbach, Head of the Königstuhl State Observatory. “However, in the coming decade telescopes with mirrors up to 40 meters in diameter will be placed in operation. We need new concepts to exploit the potential of these giant telescopes.” One of these innovative approaches is the reformatting of light: for example, a light beam with a cross-section in the shape of a thin line is formed from a circular beam. According to Prof. Quirrenbach, it is also possible to use relatively small spectrographs with very large telescopes if they are fed these “squeezed” light bundles.

    Heidelberg researcher Dr Robert Harris already worked with the rearrangement of starlight while preparing his doctoral dissertation. He came across micro-optic devices used by the telecommunications industry in switching centres for fibre-optic networks. They have complex functions in a minimum amount of space and are therefore suitable for reformatting light. Now Dr Harris is developing components specifically tailored to the needs of astronomy. There is a further application for these photonic systems, according to Prof. Dr Lucas Labadie of Cologne. “If several telescopes are connected to a so-called interferometer, we get sharper images than would be possible with a single telescope. For this purpose, all light bundles must be combined and superimposed with the highest precision.” Achieving this requires optimising the components and better understanding their physical properties in order to minimise light losses, as Dr Stefano Minardi and Dr Roger Haynes from Potsdam emphasise.

    The DFG funding provides for staff and laboratory equipment to develop and test new micro-optic systems concepts for use in astronomical instruments. The technology should also be made available to others working in basic scientific research.

    3
    Multicore optical fibre for use in high-precision spectrographs. The different colours and shapes show that the optical fibre mixes the incident white light and thus greatly reduces unwanted interference effects observed by the spectrograph. This is required, for example, to find earth-like planets. The optical fibre named MCF511 was manufactured at the University of Bath (UK).

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    U Heidelberg Campus

    Founded in 1386, Heidelberg University, a state university of BadenWürttemberg, is Germany’s oldest university. In continuing its timehonoured tradition as a research university of international standing the Ruprecht-Karls-University’s mission is guided by the following principles:
    Firmly rooted in its history, the University is committed to expanding and disseminating our knowledge about all aspects of humanity and nature through research and education. The University upholds the principle of freedom of research and education, acknowledging its responsibility to humanity, society, and nature.

     
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