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Featured B First Interstellar Asteroid Found

  1. Nov 12, 2017 #51

    tony873004

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    As this object continues to get observed, its trajectory gets refined. The good news is that with the latest data, Earth only gets pushed out to 2.6 AU.
     
  2. Nov 14, 2017 #52
    The IAU posted an announcement on 2017-Nov-14 concerning the newly discovered interstellar object that explained its discovery circumstances, its naming and the new designation system. The new object is now officially known as 1I/2017 U1 and named 'Oumuamua which in Hawaiian means “a messenger from afar arriving first”. This was approved by the IAU Executive Committee. It is being called a prototype of a new class of objects, an “interstellar asteroid” which is
    not gravitationally bound to the Solar System. https://www.iau.org/news/announcements/detail/ann17045/





     
  3. Nov 14, 2017 #53
  4. Nov 14, 2017 #54
    The orbit of 1I/2017 U1 was updated on 2017-Nov-13 with the issuance of
    MPEC 2017-V63 (2017 Nov. 13) 1I/`OUMUAMUA
    The latest value of the eccentricity e = 1.1992920
    The values of the orbital parameters are only changing out at the 4th or 5th decimal place.

    Observers W. H. Ryan and E. V. Ryan. submitted astrometry on 1I/2017 U1 with magnitude near 24 using the 2.4-m f/8.9 reflector telescope at Magdalena Ridge Observatory, Socorro.

    Karen Meech is PI of Hubble Space Telescope proposal 15405 titled "Which way home? Finding the origin of our Solar System's first interstellar visitor".
    Hubble is going to be used to observe 1I/2017 U1 possibly until 2018-Jan-01 when it will have faded to magnitude 27.5

    Details of the observing plan can be found online at
    http://www.stsci.edu/cgi-bin/get-proposal-info?id=15405&observatory=HST
    When observations are completed, they will show up under the HST Archive link.
    They will be used to extend the observation arc and orbit and gather light curve data.

    Spitzer Space Telescope has an approved plan to observe 1I/2017 U1.
     
  5. Nov 14, 2017 #55
    I know it's not possible but it sure would be interesting to get a probe to it,
    To see if it's composition is similar or not to solar system asteroids.
     
  6. Nov 20, 2017 #56

    DaveC426913

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    http://digg.com/2017/interstellar-object-oumuamua

    Apparently, it's a spindle - more than five times longer than it is wide.

    The article (or is it Wiki) says that some suggestions are that it is a contact binary.

    How would 2 (or more) smaller asteroids manage to make contact (and then stay in contact long enough to adhere) in such an arrangement?

    Seems to me, it's essentially two (or more) long, thin asteroids balancing on their tips against gravity.
     
  7. Nov 21, 2017 #57

    jedishrfu

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    Magnets!
     
  8. Nov 21, 2017 #58
    I've also read that it's possible those long spindles are created by molten rock being flung out from an impact and frozen like that.
     
  9. Nov 21, 2017 #59
    An object with a trajectory never seen before and a shape never seen before? That's like winning the lottery 2 weeks in a row. Folks, this is an alien craft.
     
  10. Nov 21, 2017 #60

    Filip Larsen

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  11. Nov 21, 2017 #61

    DaveC426913

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  12. Nov 21, 2017 #62
    Well it ain't stopping here, so don't worry about an alien attack:)
     
  13. Nov 21, 2017 #63
    Yeah but the hyperbolic trajectory past our Sun might be just to fool us.
    :))
     
  14. Nov 21, 2017 #64

    DaveC426913

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    It is already on its way out of the system.
     
  15. Nov 21, 2017 #65

    stefan r

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    Long, hard, no belt, and flying free. :wideeyed:

    Stalactites are long and thin. So are hoodoos.

    This article suggests asteroids in the solar system started out with odd shapes with many elongated. They get chipped and bumped into spherical shapes over time.
     
  16. Nov 22, 2017 #66
    There are several known objects with this “cigar” shape. They’re simply rare.
     
  17. Nov 22, 2017 #67
  18. Nov 22, 2017 #68

    stefan r

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  19. Nov 22, 2017 #69
    A picture tells a thousand words, remembering that the rotation takes just over 7 hours :

    eso1737f.jpg
     
  20. Nov 22, 2017 #70

    stefan r

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    I looked at that picture. A cigar 10 cm by 1 cm by 1cm would be at the peak when the long axis is perpendicular to the sun. 10x luminosity because 10x surface. A cookie with a face surface area 10x the edge surface area (3.2 x 3.2x1, or 5 x 2 x1) would have the same peak and trough.
     
  21. Nov 22, 2017 #71

    DaveC426913

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    I'm trying to visualize the axial rotation.

    I think a cookie shape would require more "lucky" fine-tuning than a spindle. The spindle is symmetrical about its long axis, so it only needs one axis to align every 8 hours in order to reflect sunlight toward Earth. A cookie-shape would need to be aligned on two axes to reflect properly. While it doesn't rule it out, it essentially means the cookie's chance is the square root of the spindle's.

    I think.
     
  22. Nov 23, 2017 #72

    mfb

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    The cookie doesn't need any tuning, while the spindle needs tuning to get a large luminosity ratio.

    No matter how a cookie is oriented and how it rotates, we see its edge on twice per rotation, and its edge points towards the Sun twice as well. With a spindle you need a lucky coincidence to have any of these events.

    Following the light curves while the object is moving through the solar system should give sufficient separation power between these two options.
     
  23. Nov 23, 2017 #73

    stefan r

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    We are basically back toward the sun so the aspect ratio of 10 may be all we know. We could try some improbable shapes too. A minorra could pull it off. King Arthurs sword excaliber. An eggshell, a hockey stick, a hollow ring.

    Is it possible that NASA reasons like "all things are spheres until there is convincing evidence that it is not a sphere". We have "convincing evidence that there is a 10:1 aspect ratio". So one axis must be long. "All things that are long must be ellipsoid and have circular circumference until proven otherwise." ...
     
  24. Nov 23, 2017 #74
  25. Nov 24, 2017 #75

    DaveC426913

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    It doesn't need to achieve edge-on or broadside orientations. Just as long as the difference between the most extreme reaches 10:1. That means it might be somewhat longer and/or narrower than the assumed 10:1.
     
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