Astronomy

Whither Warm Belts?

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Science  14 Aug 2009:
Vol. 325, Issue 5942, pp. 794
DOI: 10.1126/science.325_794d
CREDIT: PAUL KALAS, UC BERKELEY

Is our solar system's architecture—four terrestrial planets, an asteroid belt, four Jovian planets and a Kuiper belt—common across the universe? Space-based infrared observations of circumstellar disks around nearby, Sun-like stars have suggested that cold disks of dust and debris analogous to our Kuiper belt are common, whereas warmer, asteroid belt analogs appear to be much rarer. Chen et al. reanalyzed spectra acquired with the Spitzer infrared telescope of three debris disks around nearby stars, and found that the thermal emission from all three is consistent with the presence of two dust populations, one warm and one cold. For one of the stars, HR 8799, the warmer dust lies within the orbits of the three known local planets, whereas the cold dust lies outside—a structure very much resembling that of the solar system. Eleven stars are now known to have multiple dust belts around them, in potentially similar fashion to the solar system's asteroid belt and Kuiper belt; the arrangement could prove even more common.

Astrophys. J. 701, 1367 (2009).

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