Hubble Looks but Finds No Trace of Comet ISON

by Bob King on December 20, 2013

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Each of the four panels is a combination of two separate exposures made by the Hubble Space Telescope as it tracked Comet ISON's position. Had the comet been in any of these frames, it would have appeared as a small fuzzy glow or stellar point(s) in the center. The stars are trailed because the camera tracked the comet. Credit: NASA/ESA

Each of the four panels is a combination of two separate exposures made by the Hubble Space Telescope as it tracked Comet ISON’s position. Had the comet been in any of these frames, it would have appeared as a small fuzzy glow or stellar point(s) in the center. Credit: NASA/ESA

On December 18, the Hubble Space Telescope slewed to Comet ISON’s expected position and found nothing down to the incredibly faint magnitude of 25. According to astronomer Hal Weaver, who planned the ISON search, that limit implies any remaining fragments would have to be smaller than about 500 feet (160 meters) in diameter. 

Composite photo of one of two Comet ISON locations photographed by the Hubble in a way that suppresses features not in the same place. No trace of the comet is visible. Credit: NASA/ESA

Composite photo of one of two Comet ISON locations photographed by the Hubble Space Telescope. No trace of the comet is visible. Credit: NASA/ESA

Nothing is visible in any of the images in the photo panel except trailed stars and galaxies, reflections and the occasional zap of a cosmic ray. After ISON was torn asunder by the sun, there existed the possibility that comet’s remains would follow a slightly different orbit. To make sure he was covered, Weaver photographed two separate comet positions, stacking several exposures together.

Comet ISON photographed at a second location. Again, nothing detected. Credit: NASA/ESA

Comet ISON photographed at a second location. Again, nothing detected. Credit: NASA/ESA

“The images have been combined so that features not at the same place in the various images are suppressed. Any comet fragments would show up more clearly in this composite, though stars still show up as faint streaks”, writes Zolt Lavay, author of the ISONblog at the Hubble site.

Again, nothing shows up in these either. While no one can say that ISON has completely disappeared, we now know that at the very least it’s broken into pieces too small for even Hubble to see. What was once a beautiful sight in binoculars has expanded into a vast cloud of gas and dust thinner than Ebenezer Scrooge’s gruel.

About 

I'm a long-time amateur astronomer and member of the American Association of Variable Star Observers (AAVSO). My observing passions include everything from auroras to Z Cam stars. Every day the universe offers up something both beautiful and thought-provoking. I also write a daily astronomy blog called Astro Bob.

Dogov December 20, 2013 at 8:59 PM

That sucks. Keep looking.

stephanie magnin December 20, 2013 at 10:15 PM

It is fine, extremely.

stephanie magnin December 21, 2013 at 1:47 AM

There is one way only, to find what you are looking for, of what remains. In two days, way more space. Counter-reflection -> slight change of angle, pt. + 01 up (is it still points?). It’s not going to hang around to make you happy. Basically, you stand no chance. Still, hubble it and be quick!

For Dogov’s sake, dont just look, find it.

stephanie magnin December 20, 2013 at 10:25 PM

And thanks for the great pictures! Perfect!

stephanie magnin December 21, 2013 at 2:14 AM

Although, not convinced by what is described here as Scattered light, honestly, please review and get back to us.

Donna Kunst December 21, 2013 at 7:16 AM

only time will tell,surely not nasa…

Sean Cassidy December 22, 2013 at 10:29 AM

yeah they made me look at that red laser-beam thingie to erase my memory once.

jmi0112 December 21, 2013 at 8:35 AM

The comet of the century just gone like that. I was so looking forward to it’s pass on the way back. Thanks so much for the pics astroglide Bob.

Guest December 21, 2013 at 8:54 AM

Broken into pieces too small, so matter vanished :D

Messe December 21, 2013 at 8:56 AM

It must be an illusion, ison debris not going above earth it must be going below

Sean Cassidy December 22, 2013 at 10:27 AM

no way it is gonna go right thru us! well you anyway.

Bob King December 21, 2013 at 10:08 AM

You’re welcome jmi!

teacookies December 21, 2013 at 4:14 PM

Well darn.

teacookies December 21, 2013 at 4:15 PM

I agree!

Olaf2 December 21, 2013 at 4:18 PM

I have this incredible annoying 5 series of icons at the center left om my screen with the FB, Twitter, G+ Pinterest and email that screams for attention and even blocks my text of Universe Today.

I did not have this a couple hours ago. It is really frustrating and you start to hate these 5 icons and what they represent.

IVAN3MAN_AT_LARGE December 21, 2013 at 5:00 PM

Tip: Install Adblock Plus in your browser – available for Firefox, Chrome, Opera, and now also for Internet Explorer.

Fraser Cain December 21, 2013 at 5:10 PM

Of course, that makes it so Universe Today doesn’t have any revenue, and then doesn’t exist.

IVAN3MAN_AT_LARGE December 21, 2013 at 5:56 PM

I understand that and I would not mind discreet ads on the side, like they have on the SpaceWeather.com website, but when the bloody ads encroach on the article that one is reading, it gets very annoying and is more likely to put off readers from reading the article.

Fraser Cain December 21, 2013 at 6:29 PM

I just counted 31 separate ads on the Spaceweather homepage.

Also, I’ll give you an ad-free account. Email me your username.

Fraser Cain December 21, 2013 at 5:09 PM

Sorry, I’m trying to debug a problem with our sharing plugin. What’s your screen resolution?

Olaf2 December 21, 2013 at 6:34 PM

Ok in that case. I use Firefox 26.0
Delete this post when you do not need the feed-back anymore.

Screen 1920×1080
When I resize the width about half then the panels dissapear.
The panels are way too big in size to be useful.
If you reduce them to 1/4 the and not in the horizontal centre then it would mind less. Lower bottom would be good I think.

When the FF screen is a bit more than half the screen then the panel actually overlaps parts of the text. Especially when one of the mouse cursors is over it and the panel expanded a bit more to the right.

What is annoying is that it gets your concentration away from the article. It screams like “look at me”. And when you move the mouse over it then the dynamic resized screams even harder. Getting attention is good but when it attracts so much attention then people stay away from your articles too.

I do have the tendency to scroll the page to a point where any ads is off-screen. I have seen the ads, I have acknowledged the ads but did not follow it. But here we have a situation where the icons follows you even if I have decided that it is not for me. It feels like stalking.

I actually think that right lower border and much smaller would be less intrusive. I doubt that people would follow links when they get the feeling that it stalks them. It actually makes people hate the icons associated with it.

Sean Cassidy December 22, 2013 at 10:30 AM

i am using firefox and the icons are nice and small.

Sean Cassidy December 22, 2013 at 10:26 AM

on my screen the icons aren’t impinging on the text at all…

Olaf2 December 22, 2013 at 12:11 PM

Resize the width.

Sean Cassidy December 23, 2013 at 3:08 AM

well, i mean, i’m happy they’re not covering the text. so i will leave the width alone.

Seven Star Hand December 21, 2013 at 7:34 PM

Looking for love (ISON…) in all the wrong places, perhaps? Could not the tumbling breakup seen after perihelion have caused the larger fragments to tumble outside of the predicted path for a surviving solid nucleus, like billiard balls or shotgun pellets always do? Sorry to say this, but seems that NASA is being less thorough than one would hope. Weren’t they also looking in the wrong spot during the perihelion live show, where they said nothing survived? Now move along citizens, nothing to see here, we’re in charge, no need for panic…

InTheory December 21, 2013 at 8:24 PM

I’d love to get some good estimates of some of the details not readily available to us mere mortals like distance from solar surface at perihelion, maximum velocity and tidal forces at perihelion and the temperature and density of the corona at perihelion.

I’d also love to see a good computer simulation of ISON’s final few hours. I regret ISON not surviving to be a spectacular sight, but I think the disintegration of ISON was an incredible learning experience.

I know STEREO and SOHO have a number of instruments that study the solar surface directly. Was ISON captured by any of these instruments as well, or was it just too dim and small?

BCstargazer December 22, 2013 at 1:30 PM

all the data that you ask about has been readily available for several months. SOHO, both STEREO’s, SDO, HST, MESSENGER, MRO, Swift, SST, Deep Impact and other spacecrafts took detailed pictures of ISON. computer simulations of the comet trajectory are also widely available. The prevailing discussions now are suggestions that the comet was possibly composed of a large volume of exotic ices that out gassed early and made it visible while still in a region of our Solar System where water is still in a solid state.

InTheory December 23, 2013 at 9:34 AM

I’ve seen a few estimates of size, speed and distance from the sun, but this was prior to perihelion. I’m guessing that the numbers we have now are more accurate but news about ISON after its becoming an ex-comet has been pretty sparse.

Aqua4U December 22, 2013 at 1:50 AM

Hmm… mostly gas, explosively expelling shocked dust grains.. POOF!

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