Reports

Fluorescent Hydroxyl Emissions from Saturn's Ring Atmosphere

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Science  26 Apr 1996:
Vol. 272, Issue 5261, pp. 516-518
DOI: 10.1126/science.272.5261.516

Abstract

Just before Earth passed through Saturn's ring plane on 10 August 1995, the Hubble Space Telescope Faint Object Spectrograph detected ultraviolet fluorescent emissions from a tenuous atmosphere of OH molecules enveloping the rings. Brightnesses decrease with increasing distance above the rings, implying a scale height of about 0.45 Saturn radii (RS). A spatial scan 0.28RS above the A and B rings indicates OH column densities of about 1013 cm−2 and number densities of up to 700 cm−3. Saturn's rings must produce roughly 1025 to 1029 OH molecules per second to maintain the observed OH distribution.