ISON Image of the Week

The Final Nail in the Coffin?  (Dec 23, 2013)

Plenty of stars in this Dec 18 Hubble image, but no sign of comet ISON or its dusty remains. [Image credit: NASA/Hubble]
Well, we tried our best. Even though comet ISON rapidly faded from view following its spectacular perihelion passage, we held out hope that maybe enough of a dust trail would persist that ground-based astrophotographers could see something.

Regrettably, our pick of the week last week delivered the bad news that even the deepest searches from the ground were yielding nothing but a star-filled sky in a region of space that we hoped would be dominated by a spectacular comet. And thus our very final shreds of hoped hinged upon the most sensitive eyes we have: the Hubble Space Telescope.

Until now Hubble has been unable to point in the direction of ISON's predicted remains as that would mean pointing the delicate optics closer to the blinding Sun than they are safely allowed to do. But that changed on December 18, 2013, when a team of scientists swung the giant observatory in the direction of ISON's orbit to see if anything remained - even if it was just a tiny inert lump of rock, or a fuzzy dust cloud. The image opposite is what they saw.

The guys over at the HubbleSite blog give the full details, but the bottom-line is pretty simple: Hubble saw nothing.

OK, not quite nothing. It saw everything it would be expected to see, such as stars and galaxies for example. But in terms of our beloved comet, nothing. No sign of rock or dust. This negative observation was supported a few days earlier by the Arecibo Observatory which also attempted to ping ISON with its ultra-powerful 300-meter radio telescope, but they too found nothing.
So, do we have any more tricks left up our sleeve? Umm... not really, no. The space-based Spitzer and Chandra telescopes may still glance in that direction, but chances of detecting anything are, at this stage, incredibly slim at best. But what that does mean is that scientists can now turn their attention to analyzing the extraordinary data set that we have accumulated over the past year or so. And make no mistake: thanks to the combined efforts of an unprecedented army of hundreds of amateur and professional astronomers and scientists, we've amassed unquestionably the broadest and largest data set about a single comet ever obtained. Over the coming weeks, this data will be used to fill in the blanks we have in comet ISON's story, and hopefully put one or two pieces in the bigger picture of how our solar system was put together a few billion years ago.

We will go a little quieter on this website now, but check back from time-to-time as we give occasional updates and share news. We also have a few tremendously exciting comet-related events occurring next year, so even though we are going a bit quieter on comet ISON, please do not think you've heard the last from us!

Every week this year we will put up a new image related to Comet C/2012 S1 (ISON). If you have a cool image you'd like us to consider, please send it to sungrazer@nrl.navy.mil, along with a description and any credits you would want applied. We'll contact you if we choose to use your image on the CIOC Website.

See our ISON Image of the Week Archives for earlier picks!