Detection of exospheric O-2(+) at Saturn's moon Dione

作者：Tokar R L^*; Johnson R E; Thomsen M F; Sittler E C; Coates A J; Wilson R J; Crary F J; Young D T; Jones G H

来源：Geophysical Research Letters, 2012, 39: L03105.

DOI：10.1029/2011GL050452

During a close pass of Cassini through the plasma wake of Saturn's moon Dione on April 7, 2010 the Cassini Plasma Spectrometer (CAPS) detected molecular oxygen ions (O-2(+)) on pick up ring velocity distributions, thus providing the first in situ detection of a neutral exosphere surrounding the icy moon. The density of O-2(+) determined from the CAPS data ranges from 0.01 to 0.09 /cm(3) and is used to estimate the exosphere O-2 radial column density, obtaining the range 0.9 to 7 x 10(11)/cm(2). CAPS was unable to directly detect pick up H2O+ from the exosphere but the observations can be used to set an upper limit to their density of similar to 10 times the O-2(+) density. Citation: Tokar, R. L., R. E. Johnson, M. F. Thomsen, E. C. Sittler, A. J. Coates, R. J. Wilson, F. J. Crary, D. T. Young, and G. H. Jones (2012), Detection of exospheric O-2(+) at Saturn's moon Dione, Geophys. Res. Lett., 39, L03105, doi:10.1029/2011GL050452.

• 出版日期2012-2-9