A false-color far-IR image of U Hydrae at 90 micron taken with AKARI's Far-Infrared Surveyor (FIS)
A false-color far-IR image of U Hydrae at 90 micron taken with AKARI's Far-Infrared Surveyor (FIS), showing a shell of cold dust (45 degrees Kelvin = −228 ℃). This dust shell is seen in all far-IR bands of FIS at 65, 90, 140, and 160 microns. U Hydrae's far-IR dust shell is one of the brightest and most extended case ever observed, and therefore, is a very rare and valuable case in which the structures of the dust shell can be investigate in great detail. Subsequent numerical modeling has suggested that the dust shell has a hollow structure with a physically very thin wall. Such a thin dust shell is thought to have been produced by an intermittent mass loss.