Ison Comet

  1. Last edited by a moderator: Jan 11, 2013
  2. jcsd
  3. davenn

    davenn 3,464
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    could be fun :)

    you should have posted this in the astro events section

    maybe one of the mods would like to move it to there :)

    Dave
     
  4. I sincerely doubt it will be brighter than the moon. What is it's albedo, size, and closest approach to the Earth?
     
  5. During the final stage near the sun the Ison comet will be visible during the day and brighter than the moon.
     
  6. russ_watters

    Staff: Mentor

    A comet's brightness doesn't have much to do with albedo and size prior to entering the inner solar system. It's a comet -- what we see is mostly gas and dust, ejected when it nears the sun.

    But:
    May. It may be brighter than the moon. It is still very iffy at this point. We won't even know if it will survive its brush with the sun until it happens and it will change very rapidly. So every day will be like opening a Christmas present for astronomers. I just hope it isn't socks.
     
  7. Can't wait, if it's as good as Hale-Bopp was, I'd be very happy.
     
  8. I tend to agree with your slight scepticism. Predicting appearance even with good data is nothing but speculation. I remember all the hullabaloo about the return of Halley’s. What a let down!
     
    Last edited: Mar 4, 2013
  9. So I checked it out and found it on Starry Night. Although next to the sun, this is the brightest at an impressive -8.23 magnitude!

    [​IMG]

    This is how close it will be to eclipsing the sun! That would have been incredible, but if its accurate, I bet you could still see it clearly behind a solar filter.

    [​IMG]

    And brightest after sunset

    [​IMG]


    But, let me just mind you that the tail is exaggerated... alot... but still worth gazing atevery second.
     
  10. NascentOxygen

    Staff: Mentor

    Something like 30-60km across. Apparently there is an even chance it will collide with Mars. If so, at 60km/sec it should leave a crater around 300km across. The fireworks will be visible to the naked eye from Earth, for those favourably positioned. Were it to collide with Earth, the result would be similar to the event that wiped out the dinosaurs.

    That's a few details I remember from a recent astronomy broadcast.
     
  11. davenn

    davenn 3,464
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    no ... wrong comet
    This one is the possible Mars contender .....
    C/2013 A1 (Siding Spring) is a new discovery by Robert McNaught on January 3. This comet will pass very close to Mars on the 19th of October 2014. There is a small possibility that it may impact the planet! It is not currently observable visually

    Dave
     
  12. Borg

    Borg 1,097
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    If it did hit, can you imagine the pictures that some of the rovers might get right before they're vaporized?
     
  13. russ_watters

    Staff: Mentor

    It isn't necessarily exaggerated. In fact, it may be under-playing it. The tail could be long enough to stretch nearly from horizon to zenith, but what Starry Night doesn't pick up is that the comet is moving so fast that the tail drags across the sky like a fan. See The Great Comet of 2007:

    [​IMG]
     
  14. davenn

    davenn 3,464
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    ahhhh indeed :)


    D
     
  15. davenn

    davenn 3,464
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    I well remember the impact marks on Jupiter of Shoemaker-Levy9 in 1994
    WHAT an amazing birthday pressie!!

    I didnt have the ability to photo the impact sites back then, but seeing those black marks on Jupiter through my own scope was awesome

    Dave
     
  16. russ_watters

    Staff: Mentor

    I'm buying a new camera for Ison. I would have for SL-9 too, had I not still been in high school and amateur webcam/ccd astrophotography not been invented yet...
     
    Last edited: Mar 14, 2013
  17. NascentOxygen

    Staff: Mentor

    Even if there isn't a direct hit, the astronomer said that it could well spell the end of our spotlight on Mars. Our Mars satellite/s that relay data from the Rovers will not fare well. The comet by the time it passes Mars is likely to have broken up into something akin to an expanding swarm of rocks, gravel and smaller particles, and some are sure to head towards Mars. The particles and the cloud they kick up may destroy the satellites, and with that our vital link to the Rovers.
     
  18. NascentOxygen

    Staff: Mentor

    Oh, I stand corrected. Two big comets in short time.
     
  19. mfb

    Staff: Mentor

    It looks unlikely that C/2013 A1 (Siding Spring) is an issue for the rovers and satellites at mars, unless it comes extremely close or hits Mars. See this article for details.

    ISON will come close to Mars (0.07 AU) as well, but without a reasonable impact probability.
     
  20. How often have we found "dynamically new comets" before this?
     
  21. Borg

    Borg 1,097
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