Comet ISON may be toast early on

ISON Comet captured by HST, April 10-11, 2013.jpg

C/2012 S1 as captured by Hubble Space Telescope on 10–11 April 2013


Call it premature disintegration? A cometary astronomer has identified signs in the spectra of Comet ISON that are consistent with a poorly understood process of rapid disintegration. A new webpage has been established here to track this dramatic event should it unfold. We’ll know in the next few weeks:

Emailed Press Release — In a recent letter posted to Cornell University arXiv preprints repository (, Prof. Ferrin presented and discussed what he identified as a peculiar photometric signature previously observed in disintegrating comets. In his own words “when I saw this signature I immediately went to my database of comet light curves, and found that two comets had also presented this signature: Comet C/1996 Q1 Tabur and Comet C/2002 O4 Hönig; to my surprise these two comets had vanished turning off or disintegrating.” According to Prof. Ferrin this observation is irrefutable evidence that Comet ISON is following the same path of those defunct comets. The following few weeks will reveal the real fate of weird Comet ISON.

Interestingly a comparison between the light curves of ISON and eight previously disintegrating comets is allowing Prof. Ferrin to predict that the object has already entered into a sort of “danger zone” using his own words. No theoretical model exists capable of explaining all the observed phenomena with those defunct comets.

Several well known facts about the strange behavior of Comet ISON should be widely recognized. It was expected that the comet would bright up after passing the “frost line,” a distance at which comets tend to turn on water production. Some astronomers locate this line between 2.5 and 3 AU. But the comet has already passed that line and almost none has occurred. This was the last chance of the comet to exhibit some healthy activity but ISON has surprised experts by maintaining almost unmodified its photometric behavior.

Additionally ISON faces other challenges as it approaches to the inner solar system. First, the comet will reach perihelion very near the Sun, where Prof. Ferrin has calculated a temperature of 2,700 degrees Celsius, high enough to melt iron and lead. Second, besides this trial by fire, the comet will penetrate the solar Roche limit. Any object penetrating this forbidden limit will experience solar tides that may tear apart the nucleus of the comet. The combination of temperature, radiation and tides may prove too much for the comet, which may not survive the encounter with the Sun.



  1. Matt G says

    So much for the Christmas Comet. God should have built it a bit sturdier. We’re probably being punished for not keeping the Christ in Christmas….

  2. says

    My fundie mother-in-law will be disappointed if this happens. She’s convinced that the comet’s name (“I, SON”) is proof that Jesus is a-comin’ any day now.

  3. StevoR : Free West Papua, free Tibet, let the Chagossians return! says

    Well, I’m not surprised but I’m saddened if ISON doesn’t live up to early hype and shatters and fizzles out too early.

    OTOH, I guess we can still hope ISON’s breakup (assuming that occurs) could give us two comets for the price of one like Biela’s Comet :

    although probably briefly.

    I also wonder at Comet Lovejoy’s (a.k.a. Great Xmas Comet of 2011’s) remarkable survival – although again probably not for overly long – and what comparisons and contrasts might be drawn here.

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