Title

Water vapour jets inside the plume of gas leaving Enceladus

Authors

Authors

C. J. Hansen; L. W. Esposito; A. I. F. Stewart; B. Meinke; B. Wallis; J. E. Colwell; A. R. Hendrix; K. Larsen; W. Pryor;F. Tian

Comments

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Abstract

A plume of water vapour escapes from fissures crossing the south polar region of the Saturnian moon Enceladus(1-6). Tidal deformation of a thin surface crust above an internal ocean could result in tensile and compressive stresses that would affect the width of the fissures(7); therefore, the quantity of water vapour released at different locations in Enceladus' eccentric orbit is a crucial measurement of tidal control of venting. Here we report observations of an occultation of a star by the plume on 24 October 2007 that revealed four high- density gas jets superimposed on the background plume. The gas jet positions coincide with those of dust jets reported elsewhere(8) inside the plume. The maximum water column density in the plume is about twice the density reported earlier(2). The density ratio does not agree with predictions(7)-we should have seen less water than was observed in 2005. The ratio of the jets' bulk vertical velocities to their thermal velocities is 1.5 +/- 0.2, which supports the hypothesis that the source of the plume is liquid water, with gas accelerated to supersonic velocity in nozzle- like channels(9).

Journal Title

Nature

Volume

456

Issue/Number

7221

Publication Date

1-1-2008

Document Type

Article

Language

English

First Page

477

Last Page

479

WOS Identifier

WOS:000261170500032

ISSN

0028-0836

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