Planet-Forming Disk Vanishes In Less Than Two Years

Poof! Planet-Forming Disk Vanishes Into Thin Air

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Some 460 light-years away in the constellation Centaurus, a thick disk of dust swirled around a young star named TYC 8241 2652 1, where rocky planets like our own were arising. Then, in less than 2 years, the disk just vanished. That's the unprecedented observation astronomers report in a new study, out today. Even more intriguing: The same thing may have happened in our own solar system.

Born about 10 million years ago, the TYC 8241 2652 1 system was chugging along just fine before 2009. Its so-called circumstellar disk glowed at the infrared wavelength of 10 microns, indicating it was warm and lay close to a star—in the same sort of region that, in our own sun's neighborhood, gave rise to the terrestrial planets Mercury, Venus, Earth, and Mars. The infrared data reveal that the dust was about 180°C and located as close to its star as Mercury is to the sun.

By January 2010, however, nearly all infrared light from the dusty disk had vanished. "We had never seen anything like this before," says astronomer Carl Melis of the University of California, San Diego. "We were all scratching our heads and wondering what the hell did we do wrong?" But subsequent observations with both infrared satellites and ground-based telescopes confirmed the surprising discovery, he says: "The disk was gone."

Nature letter (behind paywall) Rapid disappearance of a warm, dusty circumstellar disk

Poof?!?!?!

-M-

Erm... wow. That's pretty spectacular.

Is it possible the 10 µm excess observed in 2008 came from an impact of an asteroid onto a planetary body much further from the star? The dust would have cooled over time, not being as close to the star, and the 10µm excess would have been muted. Is this feasible?

Paper is on arXiv

Arguments against the disc being protoplanetary, and for it being produced by collisions.

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The absence of strong hydrogen Balmer Hα emission in our optical spectroscopic measurements indicates that the star was not undergoing accretion of hydrogen-rich material at any significant level (see also Supplementary Information), and thus it is unlikely that such material was being transported inward to the star as would be expected in a system with an active protoplanetary accretion disk. Another argument against TYC 8241 2652 1 having a protoplanetary accretion disk in the two decades before 2009 lies with the Herschel/PACS measurements. The sensitive upper limits in the far-infrared robustly rule out the presence of a substantial reservoir of cold disk material typical of those seen in protoplanetary disks. We thus conclude that the dusty material orbiting TYC 8241 2652 1 is the result of the collisions of rocky objects.