Jovian Extinction Event (JEE)
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Modeling the Jovian
dust field, moon atmospheres, Europa geysers, and Io’s Torus through JEE
Jovian Extinction Events (JEE) occur
when an object experiences a loss of intensity as it passes behind dust or gas
in the Jovian system. This loss of light or extinction can be caused by
material gravitationally bound around one of Jupiter’s four major moons,
material trapped in the magnetosphere or torus ring that surrounds Jupiter near
Io’s orbit, or possibly Europa water geysers (paper pending). One can use an
object passing behind a target of interest to probe the material around the
object in front by measuring the change in light of the object behind as its
light passes through the this material. Here is some good FAQ material:
http://scottysmightymini.com/JEE/2014IOTA_JEE2014CFO_Final.ppsx
The extinction phenomenon was first detected in 2009 during the end of the
Jupiter Mutual Event (JME) season when Jupiter’s orbital plane was still edge
on enough that the major moons were eclipsing and occulting each other
(Degenhardt et. al, 2010). It was noted then that an anomalous photometric
dimming began many minutes prior to Io occulting Europa or when Europa occulted
Io, and an anomalous brightening was observed over many minutes post
occultation.
The material surrounding Io migrates away and is captured for a period of time
in Io’s Torus ring. When Io passes through the tips of the
torus where the extinctive material is collimated to our line of sight that Io
experiences a self extinction of its reflected light. During the
IAEP2009 and JEE2010 Observing Campaigns it was established that Io suffers a
sort of “self-extinction” while it transits its own orbit at the tips inside
the Torus of Io. There is enough stray gas and particles to cause detectable
magnitude loss with standard unfiltered observing equipment via extinction of the
reflected sunlight from Io as it is diminished by the collimated line of sight
Torus material at the most extreme eastern and western tips of the Torus. In
2010 John Talbot of New Zealand captured 5 hours of video during most of an Io
transit of its western Torus tip. At that time in November of 2010 the orbit of
Io was only 0.4 degrees inclined to our view from earth. This presented a large
amount of Torus material collimated to our view which caused a very notable
0.13 unfiltered magnitude dimming during its transit through the western torus
tip. The data from that run enabled us to derive a 5th order
polynomial fit to Western Torus Tip transits of Io and has enabled us to create
reliable predictions of future Io Torus JEE.
The Torus does have a wobble relative to Io’s orbit, so Io is sometimes
in the Torus material and sometimes out. The following discussion explains this
better: http://scottysmightymini.com/JEE/IoTorusJEE_Discussion2014-Mar-08.pdf
2009 JEE events were detected around JME occultations where the body of the
target moon in front passed directly in front of the probing moon in back. From
early 2010 to late 2014 there were no JME occultations involved. Instead
conjunctions (near occultation) occurred where the target moon passed in front
of the probing moon from our line of sight and the probing moon was separated
by up to 10 arc seconds. Thus the moon in back was probing regions above or
below the poles of the target moon. Predictions of dimming were initially based
on a first order assumption of a spherical distribution of material around a
target using trends observed in 2009 at the equators. The IAEP2009 and JEE2010-JEE2013
Observing Campaigns yielded new anomalies. We have a paper pending on this anomaly
likely linked to water geysers on Europa. We hope to document more of these
anomalies and will eventually have an entire new predictions and results
section just for Europa water geysers once additional observations validate
this theory.