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Thread: Comet C/2011 W3 Lovejoy about to fry near the sun

  1. #1 Comet C/2011 W3 Lovejoy about to fry near the sun 
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    A newly discovered comet is about to enter the SOHO LASCO C3 field of view. It could be the most spectacular seen in SOHO images in many years, or possibly ever.

    It was discovered in images taken by Austrailian astronomer Terry Lovejoy taken Novenmber 27th.

    It will pass within about 140,000 km of the solar surface and likely be destroyed on Dec 16th.

    It is too close to the sun to be seen from earth, which is a real shame, since it might become as bright as Venus.

    It is a member of the Kreutz group of sungrazing comets, all believed to be remnants of the breakup of a progenitor comet in 1106 AD.

    The majority of comets that SOHO sees belong to this group, more than 1600 of the over 2100 it has discovered.

    Once it shows up in the SOHO images, I will post a link here to the SOHO Movie Theater, and instructions on how to use it

    For now, you can see it here from a few days ago from the STEREO B spacecraft:

    http://sungrazer.nrl.navy.mil/index....hi1b_Dec11.gif


    MW
    Attached Images


    Last edited by MeteorWayne; December 13th, 2011 at 06:33 PM. Reason: It's me...typos
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  3. #2  
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    OK, it has finally shown up.

    The way SOHO's LASCO C3 wide field coronagraph works:

    It takes 5 images an hour. But there are often transmission delays, so it takes a while to fill in all the slots; for example, as I look now, there is a gap from 12/14 00:18 to 12/14 08:30. The other frames will slowly be filled in. The coronagraph occults the sun so the inner regions can be seen; the small yellow circle inside the blocked area is the actual size of the sun.

    So, Go here:SOHO Movie Theater

    Select LASCO C3 as the image type.

    In the upper right, enter 2011-12-13 as the start date, and 2011-12-15 as the end date.

    Then hit search.

    There is a very small related precursor comet visible 12-13 beginning at 11:30 just below and to the left of the sun. it slowly moves straight up, and doesn't begin to sport a tail until the very end, after about 23:00, and gets hard to see amonth the light spillage.

    If you back up and select LASCO C2 instead, you get a much closer view; the tiny comet shows up about 20:00 on the 13th before sublimating away.

    Comet Lovejoy is, as you can see at 08:30 MUCH bigger and brighter; too bright to miss!! It is coming in from just about the 6:00 position, moving straight up, with the narrow tail pointing directly away from the sun.

    BTW, these are LARGE files, and even on a high speed connection take a while to load. Your patience will be rewarded. Check back later as well as the missing frames get filled in.

    If you have dial up, prepare to leave it running overnight to load.


    brane wave likes this.
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  4. #3  
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    Very cool! Do we know how large this comet is? Filix.
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  5. #4  
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    Quote Originally Posted by filix View Post
    Very cool! Do we know how large this comet is? Filix.
    Not for sure, last estimate I saw was that the nucleus was ~200 meters, actually pretty large for the average Kreutz comet.

    I'm sure that will change with more data.
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  6. #5  
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    Since there is so little interest, this will probably be my final post in this thread

    Anyhow, the comet survived perihelion including spending an hour in the million degree solar corona. Amazing.

    To see it on the SOHO LASCO images, select either C2 or C3 and use 2011-12-14 as the start date, and 2011-12-16 as the end date (though that mill probably need to be extended, since it's still quite bright and might be visible to the 18th).

    There's also lots of other very cool images from other satellites, but I don't want to annoy anyone.
    Everyone has their own interests, I guess.
    Last edited by MeteorWayne; January 3rd, 2012 at 08:14 AM. Reason: Typos
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  7. #6  
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    OK, I lied. One more final post:

    Just WOW!

    The missing LASCO frames from 0:30 to 05:30 have been filled in. On the LASCO C2 you can now see the comet coming out from behind the sun. VERY SMALL and dim! Over the next few hours, it brightens (creates a coma).

    On the C3, it now has redeveloped a tail, as I expected.

    Absolutely AMAZING!!!

    The science from this will go on for years.

    MW
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    Very interesting...i noticed large CME's as the comet disappeared behind the sun...is that related ?
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    Quote Originally Posted by brane wave View Post
    Very interesting...i noticed large CME's as the comet disappeared behind the sun...is that related ?
    No, CME's happen all the time, especially small ones like that.
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  10. #9  
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    Quote Originally Posted by MeteorWayne View Post
    Anyhow, the comet survived perihelion including spending an hour in the mikkion degree solar corona. Amazing.
    According to "The Astronomy Picture of the Day" Website the comet came within 120,000 kilometres of the surface of the Sun.
    I am also very surprised it survived!
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  11. #10  
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    MeteorWayne,

    (somehow) the comet survived perihelion including spending an hour in the million degree solar corona. Amazing.
    parenthesis added

    This could be food for calculative thought

    footnote: The corona of the sun is very hot but its atmospheric pressure at the comet's grazing altitude was very low so that the equivalent temperature conduction rate at that altitude compared to the Earth's atmospheric conduction rate at its surface, for instance, would be at a substantially lower rate; I would speculate by maybe a factor of roughly a hundred. I'm saying that the temperature of a million degrees for the comets survival while passing through the corona seems very high until one realizes that there is much less heat conduction to the comet at this altitude seemingly enabling its survival.
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  12. #11  
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    Quote Originally Posted by MeteorWayne View Post
    Quote Originally Posted by filix View Post
    Very cool! Do we know how large this comet is? Filix.
    Not for sure, last estimate I saw was that the nucleus was ~200 meters, actually pretty large for the average Kreutz comet.

    I'm sure that will change with more data.
    I saw a recent estimate, on the NASA website, that the diameter of the comet's core must have been at least 500 metres.
    I remain amazed such a relatively small dirty "snowball" survived such a close encounter with the Sun.
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    I would have thought that at that distance, it must have gone through some violently powerful magnetic fields.
    If there had been any electrically conducting material in the comet, I would have thought it would have been heated by induction effects as well.
    I believe in nothing, but trust gravity to hold me down and the electromagnetic force to stop me falling through
    Physics is the search for the best model not the truth, as only mythical beings know that.
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