Is Comet ISON Dead?

 

On November 28, Comet ISON – which began its journey from the Oort Cloud some 3 million years ago – went through a major heating event, and likely suffered a major disruption.

At this time, scientists are not sure how much of the comet survived intact but would like to understand the fate of Comet ISON.

Was the bright spot seen moving away from the sun simply debris, or was a small nucleus of the original ball of ice was still there?

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Twelve NASA spacecraft assets had an opportunity to observe Comet ISON, including the Heliophysics solar observatories; Solar Dynamic Observatory, STEREO and SOHO.

Most agree that ISON was destroyed (with greater than 90% probability of this having occurred), leaving behind small (< 10 m radius) pieces of rubble, but perhaps, with maybe 10% probability of occurring, also leaving behind some important fragments 100m radius or larger, big enough to study.

At this point, though, scientists are waiting for a variety of telescopes to make observations before the status of Comet ISON can be confirmed.

What remains of Comet ISON appears to brighten and spread out, and then fade.

The disappearance of a strong central brightness condensation after perihelion is telling, the comet is clearly fainter and more diffuse going out than going in, but it continues to shine.

The spread out light is likely due to dust emitted in the few hours before perihelion going around the sun.

We have seen comets come close to the sun and disrupt and disappear before, like Comets Lovejoy and Elenin in 2012. We have also seen them survive in much smaller pieces, like the Kreutz sungrazer family progenitor and Comet Kohoutek in 1973. NASA will monitor the comet for the next several weeks.

If there is nothing sizable and stable left, it will dissipate and disappear in this time, as already emitted dust leaves the vicinity.

If there is still a central source of emission, even if it is very much smaller, we will see a new, much fainter coma and tail form, which currently may be overwhelmed by the dust emitted from before the disruption event, according to NASA.


Comet ISON’s Full Perihelion Pass

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There’s no doubt that the comet shrank in size considerably as it rounded the sun and there’s no doubt that something made it out on the other side to shoot back into space.

By monitoring its changes in brightness over time, scientists can estimate whether there’s a nucleus or not, but our best chance at knowing for sure will be if the Hubble Space Telescope makes observations later in December 2013.

Original article posted on Message To Eagle

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