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The Case of the Disappearing Dust

Astronomy has always taught us that planets form from vast clouds of dust and gas orbiting young stars. It’s a gradual process of accretion that takes hundreds of thousands, perhaps even millions, of years… or does it?

During a 1983 sky survey with the Infrared Astronomical Satellite (IRAS) astronomers identified a young Sun-like star with a large cloud of dust surrounding it. The star, named TYC 8241 2652 1, is 450 light years away and what they had found around it was thought to be the beginnings of a solar system – the protoplanetary disc from which planets form.

Fast forward to 2008. Astronomers observed at the same star with a different infrared telescope, the Gemini South Observatory in Chile. What was observed looked a lot like what was previously seen in ’83.

Then, in 2009, they looked again. Curiously, the brightness of the dust cloud was only a third of what it was the year before. And in WISE observations made the very next year, it had disappeared entirely.

“It’s like the classic magician’s trick: now you see it, now you don’t. Only in this case we’re talking about enough dust to fill an inner solar system, and it really is gone.”

– Carl Melis, lead author and postdoctoral fellow at UC San Diego

Abracadabra?

“It’s as if you took a conventional picture of the planet Saturn today and then came back two years later and found that its rings had disappeared,” said study co-author and circumstellar disk expert Ben Zuckerman of UCLA.

It’s always been thought that planets take some time to form, in the order of hundreds of thousands of years. Although that may seem like forever to humans, it’s quick in cosmic time scales. But if what they’ve seen here with TYC 8241 is in fact planetary formation, well… it may happen a lot faster than anyone thought.

On the other hand, the star could have somehow blown all the dust out of the system. More research will be needed to see if that was the case.

The really interesting thing here is that astronomers have traditionally looked for these kinds of dust clouds around stars to spot planetary formation in action. But if planets form quicker than we thought, and the dust clouds are only fleeting features, then there may be a lot more solar systems out there that we can’t directly observe.

“People often calculate the percentage of stars that have a large amount of dust to get a reasonable estimate of the percentage of stars with planetary systems, but if the dust avalanche model is correct, we cannot do that anymore,” said study co-author Inseok Song, assistant professor of physics and astronomy at the University of Georgia. “Many stars without any detectable dust may have mature planetary systems that are simply undetectable.”

Read more in the news release from the University of Georgia.

Top image: Gemini Observatory/AURA artwork by Lynette Cook.

About 

A graphic designer in Rhode Island, Jason writes about space exploration on his blog Lights In The Dark, Discovery News, and, of course, here on Universe Today. Ad astra!

Comments on this entry are closed.

  • slyg4m3r July 5, 2012, 7:48 PM

    If the history channel gets wind of this, they’ll add it to their next episode of Ancient Aliens..

    • Skipdallas July 5, 2012, 8:47 PM

      Yeah, it is sad what the History channel has turned into. Being a History Buff, I was excited when it started. Now it is more akin to the “National Enquirer” than a reputable source of knowledge. Stories about aliens, and “Bigfoot”. Give me a break.

      • IVAN3MAN_AT_LARGE July 5, 2012, 9:56 PM

        That’s because you’ll never go broke catering for the lowest common denominator!

        • Skipdallas July 5, 2012, 11:16 PM

          Too true. It’s all about the money and placating the masses with tripe.

          • Aqua4U July 7, 2012, 1:58 PM

            It’s all about controlling the masses with one voice. There used to be a law that regulated how many and what type of news outlets any one entity/corporation could own. That law went away in the mid 90’s so now, we have half a dozen corporations owning the airwaves. Part of their SOP (Standard Operating Procedures) is thought control. They are seriously involved in the ‘dummying down’ of American culture. DON’T believe FOX news – they LIE all the time. Look what happened to the National Geographic… THAT station has become as bad as the worst of them. UFO this, UFO that… what a load of crap!

      • Aerandir90 July 5, 2012, 11:01 PM

        I feel the same way about Discovery Channel, seems to have shifted priorities, which is sad because its what inspired me to pursue an aerospace career

        *Edit*
        I’ve also noticed this off late at Space.com, too many articles related to pseudoscience and 2012 doomsday type Nbiru nonsense themes for my liking. I’ll admit its kind of a public service to denounce these things but you’re taking away space (npi) from other more newsworthy stories. It used to be my most visited site for space news; now its UT <3

        • Skipdallas July 5, 2012, 11:18 PM

          Stories about the feasibility of zombies and vampires are in the works no doubt. meh….

          • Really20 July 7, 2012, 8:31 PM

            I think they’ll just stick to UFO’s, hiding behind the fact that SETI is a legitimate search. (It is, but it in no way makes UFO shows or ufology valid.) As for space.com, it was better earlier but I can see it transforming into another popular-press website. They need to add some originality to their articles and make them longer.

      • Really20 July 7, 2012, 7:50 PM

        It’s sad that the History Channel has descended to this… fortunately there are still some reputable shows on there, like The Universe… but even that has absurdities sometimes.

        Someone needs to boycott History Channel and National Geographic until they make more intelligent shows and stop denigrating the field of study of the search for extraterrestrial intelligence with “ANCIENT EGYPTIANS GOT HELP FROM UFOS OMG.”

  • torque xtr July 5, 2012, 8:07 PM

    If there were two gas giants on unstable orbits several times farther from the star than the outer edge of the disk, then could the event of planetary scattering do the trick?
    This would require a close encounter, which sends one of the giants to a
    highly excentric orbit, like HD 80606 b – before the encounter the disk
    would be undisturbed, and after that the gas giant would rip through the dust disk from edge to edge two times a hundred days, and that sounds enough to scatter the whole of the disk very quickly…

  • Mastercope July 5, 2012, 8:33 PM

    The Moties have found a way around the “Crazy Eddie Drive” soon as they find our system has a lot of water and Iron nickel asteroids we are next.

  • CJSF July 5, 2012, 10:25 PM

    What if it just changed temperature? Might that not account for first, the fading, then the “vanishing?” What if it’s just emitting at a different wavelength now?

    CJSF

    • Eric Simpson July 6, 2012, 2:09 AM

      Yes, and it seems possibly similar to cloud formation here on earth. Often out of nowhere they just form in thin air, and disappear also. Could similar type forces be involved?

      • Lorin Ionita July 6, 2012, 7:44 AM

        That’s not an issue. Clouds are gas and they are in an atmosphere that fluctuates all the time, this is dust and it’s in space where the temperature doesn’t fluctuate. So the dust should remain the same temperature and it wouldn’t decrease in emission.

        • CJSF July 6, 2012, 11:02 AM

          Why would that necessarily be true? If whatever mechanism heated the dust to the levels initially detected was no longer operating, or some other change was occurring, wouldn’t that alter the temperature of the dust? I agree that the atmospheric cloud analogy may not be the best, though.

          • Lorin Ionita July 9, 2012, 7:14 AM

            The star is that mechanism. You are right, if the star itself would disappear then the dust would change it’s temperature, but as long as it is there the dust should keep the same temperature.

  • Michael Gibbons July 6, 2012, 1:40 AM

    I realize that anything involving “alien” action is automatically stupid, but it does occur to me that one of the more (relatively) likely forms of “life” in the universe could be Von Neumann machines, which might operate on this kind of timescale. I suppose eccentric gas giants sounds more plausible, but wouldn’t they clean up the dust slowly, at least at first?

  • Adam Kendall July 6, 2012, 2:24 AM

    This is very exciting, and I will be watching for future updates. Keep us posted, UT!

  • Zoutsteen from Holland July 6, 2012, 5:45 AM

    Magnetic pole reversal due to stellar core collapse?
    Just throwing in a term myself.

  • the_only_fan July 6, 2012, 11:53 AM

    if planets, as already commented on a previous article, aren’t born out of a dust cloud but are direct products remnants of nearby supernovae material, seeded to the star system; then it is normal that remnant clouds of a star formation are once the star is formed completely blown away or partially absorbed very quickly after the entrance of the protoplanet

  • Torbjörn Larsson July 6, 2012, 3:12 PM

    But Corot & Kepler, as well as the microlensing observations on nomads, already told us roughly the frequencies of planets.

    Aren’t they inflating the importance of this? Nice crosscheck though.

    As for the mechanism & the thread, this is part of the reason why I visit UT. I haven’t had my morning coffee yet, and I’m fed a couple of reasonable, even alluring suggestions I wouldn’t have thought of in a day, if ever.

    For myself, I would say that the gas giant resonance process would be a SOTS (“science off the shelf”) solution to plug in as a first guesstimate based on, arguably, observed physics. It certainly seems to have played hell with our system.

  • Carlos Orue July 6, 2012, 9:31 PM

    What if just like Saturns rings the protoplanetary disc has tilted so that we are now looking at the plane of the disc rather than face-on at the plate, this would give the appearance that the dust has disappeared, just like Saturns ears disappeared during Galileos observations? Just a thought.

  • Aqua4U July 7, 2012, 2:08 PM

    So if proto planetary dust rings are absorbed or incorporated into planets much more rapidly than previously assumed… how might that effect our understanding of the principal forces involved? especially that of gravitation? or the effects of solar radiation/wind?

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