Enceladus Plume Search, Nov. 27 Options

[jmknapp]

Interesting item in the science plan kernel (S16) just released to the NAIF website:

OBSERVATION_ID: S1629

SEQUENCE: S16

OBSERVATION_TITLE: Plume Search

SCIENCE_OBJECTIVE: Hope to detect/observe plumes, whether from volcanic activity or geysers.

OBS_DESCRIPTION: Point and stare.

SUBSYSTEM: ISS

PRIMARY_POINTING: ISS_NAC to Enceladus (0.0,5.0,0.0 deg. offset)

REQUEST_ID: ISS_018EN_PLUMES001_PRIME

REQUEST_TITLE: ENCELADUS Geyser/Plume Search

REQ_DESCRIPTION: 1;ENCELADUS Geyser/Plume Search 1x1xNPp -- 3 different exposures

BEGIN_TIME: 2005 NOV 27 19:00:00 UTC

END_TIME: 2005 NOV 27 20:00:00 UTC

[Bill Harris]

The ridges and wrinkles in that region are a strong indication of tectonics and therefore heat flow, so it makes perfect sense that there will be venting and visible plumes.

Now to figure out why....

--Bill

[Bjorn Jonsson]

I'm attaching a rendering I did showing the viewing geometry at 17:38 on November 27, 2005. Cassini took several images at roughly this time, for example these two:

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=54839

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=54840

I then rotated one of the Cassini images where the limb is overexposed to match the orientation of the rendered image, resized it to match the rendering size and pasted the plumes into the rendering.

This confirms that the source of the brightest plume (assuming we really are seeing plumes which seems very likely) is near the south pole. The fainter plumes appear farther from the pole. It should be noted that this might be an illusion, the brightest plume might be at the same distance or farther from the pole than the fainter ones if its source is well inside Enceladus' 'disc'.

Attached thumbnail(s)

 

[jmknapp]

This confirms that the source of the brightest plume (assuming we really are seeing plumes which seems very likely) is near the south pole. The fainter plumes appear farther from the pole. It should be noted that this might be an illusion, the brightest plume might be at the same distance or farther from the pole than the fainter ones if its source is well inside Enceladus' 'disc'.

This might help pin things down, assuming I got it accurately. Here's the viewing geometry I think, from the vantage point of an observer 100,000 km directly above the south pole:

[mars loon]

This news just released by CICLOPS website

"The Fountains of Enceledus"

http://ciclops.org/view_event.php?id=45

"In a wonderful start to the Holiday season, Cassini imaging scientists are delighted by recent sightings of fountain-like plumes towering above Saturn's moon Enceladus. A fine spray of small, icy particles, emanating from the warm, geologically unique province surrounding the south pole of Enceladus and believed now to supply the material comprising Saturn's E ring, was first observed in images taken back on Jan. 16, 2005. Images of a crescent Enceladus returned by Cassini this past weekend show multiple plumes in striking detail. Stay tuned for future announcements on the sightings of the Enceladus plumes".

check the link for more info and images