• Researchers map the movement of white dw

    From ScienceDaily@1:317/3 to All on Wed Mar 23 22:30:44 2022
    Researchers map the movement of white dwarfs of the Milky Way

    Date:
    March 23, 2022
    Source:
    Lund University
    Summary:
    White dwarfs were once normal stars similar to the Sun but then
    collapsed after exhausting all their fuel. These interstellar
    remnants have historically been difficult to study. However, a
    recent study reveals new information about the movement patterns
    of these puzzling stars.



    FULL STORY ========================================================================== White dwarfs were once normal stars similar to the Sun but then
    collapsed after exhausting all their fuel. These interstellar remnants
    have historically been difficult to study. However, a recent study from
    Lund University in Sweden reveals new information about the movement
    patterns of these puzzling stars.


    ========================================================================== White dwarfs have a radius of about 1 percent of the Sun's. They have
    about the same mass, which means they have an astonishing density
    of about 1 tonne per cubic centimeter. After billions of years, white
    dwarfs will cool down to a point where they stop emitting visible light,
    and turn into so-called black dwarfs.

    The first white dwarf that was discovered was 40 Eridani A. It is a bright celestial body 16.2 light-years from Earth, surrounded by a binary system consisting of the white dwarf 40 Eridani B and the red dwarf 40 Eridani
    C. Ever since it was discovered in 1783, astronomers have tried to learn
    more about white dwarfs in order to gain a deeper understanding of the evolutionary history of our home galaxy.

    In a study published in Monthly Notices of the Royal Astronomical Society,
    a research team can present new findings about how the collapsed stars
    move.

    "Thanks to observations from the Gaia space telescope, we have for the
    first time managed to reveal the three-dimensional velocity distribution
    for the largest catalogue of white dwarfs to date. This gives us a detailedpicture of their velocity structurewith unparalleled detail,"
    says Daniel Mikkola, doctoral student in astronomy at Lund University.

    Thanks to Gaia, researchers have measured positions and velocities
    for about 1.5 billion stars. But only recently have they been able to completely focus on the white dwarfs in the Solar neighbourhood.

    "We have managed to map the white dwarfs' velocities and movement
    patterns.

    Gaia revealed that there are two parallel sequences of white dwarfs when looking at their temperature and brightness. If we study these separately,
    we can see that they move in different ways, probably as a consequence
    of them having different masses and lifetimes," says Daniel Mikkola.

    The results can be used to develop new simulations and models to
    continue to map the history and development of the Milky Way. Through
    an increased knowledge of the white dwarfs, the researchers hope to be
    able to straighten out a number of question marks surrounding the birth
    of the Milky Way.

    "This study is important because we learned more about the closest regions
    in our galaxy. The results are also interesting because our own star,
    the Sun, will one day turn into a white dwarf just like 97 percent of
    all stars in the Milky Way," concludes Daniel Mikkola.


    ========================================================================== Story Source: Materials provided by Lund_University. Note: Content may
    be edited for style and length.


    ========================================================================== Journal Reference:
    1. Daniel Mikkola, Paul J. McMillan, David Hobbs, John Wimarsson. The
    velocity distribution of white dwarfs in Gaia EDR3. Monthly Notices
    of the Royal Astronomical Society, 2022 [abstract] ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220323101234.htm

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