Galaxy Zoo Talk

Asteroids and free planets.

  • Mjtbarrett by Mjtbarrett

    Thanks to confirmation from ElisabethB (my hero) I am pleased to confirm that I have found my first asteroid 😃 http://talk.galaxyzoo.org/objects/AGZ0002v2b
    I assume that the asteroids seen in these images are (relatively) near earth objects. I can't help wondering what sort of radius these things have, and how far out we need to go before they are no longer visible. Would free planets further out show up in a similar way and if so, would it be possible to tell the difference between the two? Can any of the objects be tracked over time??
    http://www.nature.com/nature/journal/v473/n7347/full/nature10092.html
    Or see this one if, like me, you don't want to pay! http://www.guardian.co.uk/science/2011/may/18/astronomers-discover-free-floating-planets

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  • Budgieye by Budgieye moderator

    Pluto was found in 1930, by taking photos 5 days apart and comparing them.
    The asteroids move enough in 10 minutes that we can see them in multiple places with each filter change using the SDSS telescope.
    Ice Hunters Zoo had been finding Trans-Neptunian Objects using a similar technique. Multiple exposures of IceHunters were in hours or days.
    http://www.icehunters.org/science
    http://arxiv.org/pdf/1210.4549v1.pdf

    The interesting article that you mention had found planets using microlensing.
    I suppose the multiple photo technique can only work if the telescope can actually see the planet. Hubble has seen planets around several nearby stars, so I suppose the photo technique will work for 20 light-years away, or so.

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  • Mjtbarrett by Mjtbarrett

    Thanks for taking the time to reply @Budgieye. Being new, I wouldn't have a clue whether the dark circle seen on the edge of the star in the following image was caused by a black hole, a planetary transit, a sunspot or a frozen space spider on the lens! http://talk.galaxyzoo.org/objects/AGZ0001iwq I suspect that a free planet would be virtually impossible to spot directly, but wonder if the effect of the passage of such a planet (eg microlensing during a caustic crossing event) could sufficiently "shift" the position of the other bodies to be recorded in subsequent images of the same field? Like this http://www.guardian.co.uk/science/video/2011/may/18/free-floating-planets-discovered
    I have come across lots of stars that display the three colour separation characteristic of asteroids. I understand that the most common interpretation is that they are due to filter misalignment, instrument wobble, image processing error or some such plausible explanation. I have wondered, however, if there may be an apparent movement that is seen as colour separation where the cause is physical, such as in a lensing event for example? Another explanation may be that the shape of a pulsar, for example a rapidly rotating ellipsoidal variable, changes enough over the time of the exposures to register as colour separation?
    Like the one at the start of this thread for example http://talk.galaxyzoo.org/objects/AGZ0004l74/discussions/DGZ10068gw I suppose that the question should be something along the lines of "is it possible that the effect we are seeing may sometimes be too quickly dismissed as artifact when there may be a genuine diagnostic value in determining the amount of shift in known objects of a given type?" Or something... 😃
    I'm not an astrophysicist and I am new to the Galaxy Zoo site, so this is just an effort to scratch my curiosity itch. I'm grateful that you bothered to reply. Thank you.

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