Galilean Satellite Mutual Occultations and Eclipses in 1996-1998
The next mutual event season is approaching! During this period, the
Earth and the Sun pass through the orbital planes of the Jovian
satellites, from South to North, so that the satellites eclipse and
occult one another. The main sequence of events occurs throughout
1997, but there were a few grazing events in June 1996, and also some
events in January-April 1998.
Here is an ASCII table of predictions
of all mutual events, from Jean-Eudes Arlot. (Note that these times
are in TT, which is about 62 seconds ahead of UT).
Interactive site giving
mutual event geometries at the Bureau des Longitudes, France.
Io Occultations
There will many excellent occultations of Io by the other satellites.
Infrared photometry of these can be used for high-resolution mapping of
Io's volcanic hot spots, at even higher effective spatial resolution
than the Galileo observations which will be made through the same
period. Here is an ASCII summary
of (nearly) all Io occultations, adapted from
Jean-Eudes Arlot's table by John Spencer.
Jay Goguen's Predictions
Jay Goguen has generated detailed
graphical predictions for all Io occultations. His compressed postscript files
can also be downloaded by anonymous ftp from goshawk.uwyo.edu, outgoing/ijw/mutual97.
Here is documentation for these
graphical predictions, from Jay, along with information on planned infrared
observations of the Io occultations. Observations are already in the planning
stages at several observatories, so contact Jay or John Spencer to coordinate
plans.
Please note that before midday on Sept. 26 1996, these
prediction graphics contained a bug that resulted in the minimum
satellite separations being twice what they should have been.
The bug is now fixed and the files here are now accurate, with
a few small exceptions.
Occultations of Io by the Inner Satellites
During the mutual event season Io is also frequently occulted by the
inner Jovian satellites (Amalthea, Thebe, Metis, and Adrastea). These
events are usually of no interest: these satellites are so much
smaller than Io that they produce a negligible (<1%) drop in its
reflected flux when they pass across its disk. However, when Io is in
Jupiter's shadow there is a chance that these satellites will pass in
front of a hot spot that contributes a significant fraction of Io's
total infrared flux, and could thus cause a significant drop in the
infrared light from Io that might be detectable and useful for
refining hot spot locations, shapes, and/or the satellite ephemerides.
Bill Taber of JPL has generated a list of these
events for the rest of 1997. You can get a better idea of the
geometry of each event by going to Mark
Showalter's Jupiter viewer site.
Return to IJW Satellites Home Page