THERE can be smoke without fire. Sharp rings of dust around stars aren't always carved by planets but can form on their own - bad news for those who use the structures to guide them to stars that host planets.
The discs of dust and gas debris surrounding stars (blue area in photo above) sometimes produce sharply defined or elongated rings. These were assumed to be the calling cards of unseen planets, carved by the bodies as they travel through the disc.
Now Wladimir Lyra at NASA's Jet Propulsion Laboratory in Pasadena, California, and Marc Kuchner at NASA's Goddard Space Flight Center in Greenbelt, Maryland, have shown that interactions between dust and gas alone can account for the rings.
Dust concentrates in regions of high-pressure gas. As the star heats the dust, it in turn causes the gas to heat up and expand, creating higher pressure which then concentrates more dust. Lyra and Kuchner simulated this feedback process and, with no planets in their model, created several types of structure, including elongated rings and clumps (arxiv.org/abs/1204.6322).
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Thu May 10 12:41:03 BST 2012 by Eric Kvaalen
"The discs of dust and gas debris surrounding stars (blue area in photo above) ..."
At this time there is no photo. Could we please have it?
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