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Paper: In Search of Disks: AKARI Pointed Detections of Circumstellar Material around Main Sequence Stars
Volume: 418, AKARI, a Light to Illuminate the Misty Universe
Page: 99
Authors: Fukagawa, M.; Murakami, H.; Hirao, T.; Yamashita, T.; Ootsubo, T.; Enya, K.; White, G. J.; the MP-VEGAD team
Abstract: Infrared emission above the expected photospheric flux has been detected toward a significant fraction of main-sequence stars with IRAS, ISO, and Spitzer. The existence of these excesses indicates the presence of substantial reservoirs of solid dusty material in circumstellar disks, which we are beginning to understand, can play a formative role in the history of, and physical processes involved in planet formation. The AKARI/IRC observations were designed to detect warm dust toward a sample of Hipparcos stars, to a level of about 3% of the expected photospheric emission. These were supplemented by pointed observations with the far-infrared surveyor (FIS) designed to search for evidence of colder dust grains. Forty one stars were observed using the MIR-S (7, 11 μm) and MIR-L (15, 24 μm) filters, and supplemented by observations in the four FIS bands at 65, 90, 140, and 160 μm. A further 48 stars were observed only with the IRC, and 3 brightest stars only with the FIS. The preliminary color analysis reveal that 6 of the stars show excess emission at 24 μm about 10% greater than the expected photospheric emission, and several of the other stars show hints of excess emission at lower levels. Our current detection limit at 24 μm corresponds to a fractional dust luminosity approximately 50 times larger than that of the Asteroid belt in our own solar system.
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