[X] My Assistant

[scalbers]

Java app isn't loading for me yet on that link...

[Mongo]

I'm getting nothing but time-out messages myself. Is there some other site that has the current C2 image?

[TheAnt]

xflare, you got a screengrab to share? Site is getting hammered.

Lets see if I get this one to show here.

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[scalbers]

Mongo - this site still has 1912UTC: http://soho.esac.esa.int/data/realtime/c2/1024/latest.html

TheAnt & xflare - thanks for posting!

[xflare]

Heres the latest 20.24UT

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[nprev]

Thanks, TheAnt & xflare!!! Looks like something probably made it all right, but GREATLY diminished.

[xflare]

Thanks, TheAnt & xflare!!! Looks like something probably made it all right, but GREATLY diminished.

Remember what Lovejoy looked like when it reappeared?

[TheAnt]

Thanks, TheAnt & xflare!!! Looks like something probably made it all right, but GREATLY diminished.

You're welcome Scalbers and Nprev. Edit: I add the latest image in case you still cant see that page.

ISON might still brighten by outgassing etc. It might be like one of those candles we blow out, and that start to burn again. Well in this case it's the Sun that do both the burning and blowing.

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[Mongo]

Remember what Lovejoy looked like when it reappeared?

My thoughts exactly. I would say that the chances are that not much of ISON has survived, but the possibility of another Lovejoy-type rebirth has gone from maybe 1% before these images were published to maybe 10% now (pulling these percentages out of thin air).

[scalbers]

Here are LASCO C3 and C2 animations of Lovejoy we can review for comparison. It brightened up while emerging in the C2 animation.

http://www.youtube.com/watch?v=zh3Wju3qabE

[TheAnt]

Here is a LASCO C3 animation of Lovejoy we can review for comparison.

http://www.youtube.com/watch?v=Tk6sSAqoLqM

Thank you Scalbers, I had a look at that file and Lovejoy were indeed quite dim at first. But brightened within hours.

Edit: Thank you for sharing the passage together with you guys.

[Mongo]

I'm re-posting this message from earlier today, it might be relevant to the current situation:

******re-post starts******

It seems that one theory of cometary behavior can explain ISON's dimming without assuming that it has disrupted:

posted by Jakub Cerny at 8:44 this morning at comets-ml:

Re: ISON brightening in SOHO C3 - small chance for daylight observat

Hi Filip,

seems that at least someone was expected it:

CBET 3723: 20131127 : COMET C/2012 S1 (ISON)

" J. N. Marcus, St. Louis, MO, U.S.A., writes: "Considerable sublimation of submicron-size silicate dust grains can be expected to occur in the coma and tail of comet C/2012 S1 near perihelion, if its behavior is similar to that of sungrazing comet C/2011 W3 (Lovejoy), whose nucleus survived for a few days beyond perihelion (see Sekanina and Chodas 2012, Ap.J. 757, 127). If C/2012 S1 can survive until its perihelion passage, then its brightness, based upon my preliminary photometry of C/2011 W3 in the SOHO LASCO C3 and C2 coronagraph fields, should start to fall below any power-law formula at about r = 0.1 AU (Nov. 27.8 UT), peak at magnitude -1 to -3 at r = 0.03-0.04 AU (Nov. 28.5-28.6), and then decline by 2 or more magnitudes by the time of perihelion passage on Nov. 28.8 (details of my study of photometric behavior of near-sun comets will be submitted to the ICQ soon). Thus, a strong falloff in brightness at these times should not necessarily be construed as disintegration of the nucleus. After perihelion, the comet's brightness would temporarily increase as submicron grains re-populate the coma and dust tail."

Best regards,
Jakub

So a sungrazing comet with similar properties to comet Lovejoy produces a lot of submicron-sized dust (ISON has certainly released a lot of dust, as we know). When it gets too close to the sun, the dust sublimates away and the comet's brightness falls. When it recedes from the Sun beyond the dust sublimation line, it re-brightens as newly released dust starts to contribute to its brightness. But it could be producing dust at its established rate the entire time.

Also, keep in mind that none of the pre-perihelion tail was ever expected to survive perihelion, it was always going to need to grow a new tail. What will be important for its visibility in December will be its gas and dust production rates after perihelion.

******re-post ends******

[scalbers]

Good reminder - what might be the dust sublimation radius? If it is at .03 AU, then ISON should get there at 2330UTC today.

[Explorer1]

Looks like the opposite of Lovejoy; rather a nucleus with no tail, we have a tail with no nucleus! How bizarre nature can get...

[Paolo]

it still hangs there

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