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Thread: The farthest star from our Galaxy core

  1. #1
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    The farthest star from our Galaxy core

    Which star- in our galaxy - is thought to be the farthest from the core of the same?

  2. #2
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    Quote Originally Posted by Hans View Post
    Which star- in our galaxy - is thought to be the farthest from the core of the same?
    There are at least millions of outlying halo stars. I don't think we have any means of identifying the one that is farthest out and still gravitationally bound.

  3. #3
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    Indeed it appears that stars cab be ejected from there galaxy

    https://astrobites.org/2019/07/31/__trashed-9/

    Mark

  4. #4
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    Quote Originally Posted by holmes4 View Post
    Indeed it appears that stars cab be ejected from there galaxy

    https://astrobites.org/2019/07/31/__trashed-9/

    Mark
    Yes it was that story that inspired my question.

  5. #5
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    I do recall an arxiv paper from a few years back. A red giant star had been identified something like 350,000 (??) light-years out, but was thought to be gravitationally bound to the MW.

    Can't find this now very easily.

    We have to bear in mind that only the most luminous stars can be identified at these distances. Also we have to think what is the definition of the "farthest star" - I assume it must be gravitationally bound to our galaxy, but what about interlopers from other galaxies?

    Galaxy disk stars apparently extend to over 25 kpc from the MW centre:

    Disk stars in the Milky Way detected beyond 25 kpc from its center

    https://arxiv.org/abs/1804.03064#

  6. #6
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    This paper might be of interest:

    https://arxiv.org/abs/1407.2610

    The Most Distant Stars in the Milky Way
    John J. Bochanski, Beth Willman, Nelson Caldwell, Robyn Sanderson, Andrew A. West, Jay Strader, Warren Brown
    (Submitted on 9 Jul 2014)
    We report on the discovery of the most distant Milky Way (MW) stars known to date: ULAS J001535.72+015549.6 and ULAS J074417.48+253233.0. These stars were selected as M giant candidates based on their infrared and optical colors and lack of proper motions. We spectroscopically confirmed them as outer halo giants using the MMT/Red Channel spectrograph. Both stars have large estimated distances, with ULAS J001535.72+015549.6 at 27474 kpc and ULAS J074417.48+253233.0 at 238 64 kpc, making them the first MW stars discovered beyond 200 kpc.
    Selden

  7. #7
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    Quote Originally Posted by selden View Post
    This paper might be of interest:

    https://arxiv.org/abs/1407.2610

    The Most Distant Stars in the Milky Way
    John J. Bochanski, Beth Willman, Nelson Caldwell, Robyn Sanderson, Andrew A. West, Jay Strader, Warren Brown
    (Submitted on 9 Jul 2014)
    These are beyond the MW virial radius (although there must be a large uncertainty as to what this is), plus there is significant doubt about them being gravitationally bound.

    The authors' most likely origin of these stars is stripping of other galaxies. They say they were unlikely to have been ejected from the MW itself.

    So I don't know if they should be counted as "in the Milky Way" necessarily ?

  8. #8
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    Thanks for all the replies and interesting information folks!

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