Long-wavelength Density Fluctuations Resolved in Pluto’s High Atmosphere
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چکیده
Near-infrared measurements of the occultation of star P445.3 by Pluto on 2007 March 18 reveal that Pluto’s upper atmosphere (∼200–400 km altitude) is unexpectedly dynamic. At a wavelength of 1.6 μm, numerous vertical fluctuations (8–20 km) of density are detected with unprecedented signal-to-noise ratio. These fluctuations are achromatic, nearly limb-aligned, and fully resolved along a ∼1000 km path over a pressure range of ∼0.1– 0.7 μbar (0.01 to 0.07 Pa). Vertical wavelength increases with altitude indicating a high-frequency cutoff operating on a broad-band spectrum of buoyancy (“gravity”) waves generated deeper in Pluto’s atmosphere.
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تاریخ انتشار 2008