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The Pele Plume (Io): Observations with the Hubble Space Telescope
Author(s) -
Spencer John R.,
Sartoretti Paola,
Ballester Gilda E.,
McEwen Alfred S.,
Clarke John T.,
McGrath Melissa A.
Publication year - 1997
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/97gl02592
Subject(s) - plume , wavelength , jupiter (rocket family) , physics , hubble space telescope , astrophysics , astronomy , atmospheric sciences , optics , meteorology , stars , space shuttle
In July 1996, with the Hubble Space Telescope (HST), we observed the Pele plume silhouetted against Jupiter at a wavelength of 0.27 µ m, the first definitive observation of an Io plume from Earth. The height, 420 ± 40 km, was greater than any plume observed by Voyager. The plume had significantly smaller optical depth at 0.34 and 0.41 µ m, where it was not detected. The wavelength dependence of the optical depth can be matched by a plume either of fine dust, with minimum mass of 1.2 × 10 9 g and maximum particle size of 0.08 µ m, or of SO 2 gas with a column density of 3.7 × 10 17 cm −2 and total mass of 1.1 × 10 11 g. Our models suggest that early Voyager imaging estimates of the minimum mass of the Loki plume [ Collins, 1981] may have been too large by a factor of ∼ 100. We may have detected the Pele plume in reflected sunlight, at 0.27 µ m, in July 1995, but did not see it 21 hours earlier, so the plume may be capable of rapid changes.