does a dense atmosphere exist around io?
DESCRIPTION
Does a Dense Atmosphere Exist Around Io?. John Menke. June 2014. X. X. X. Origin of Study. Degenhardt papers SAS2010, 2013, etc. Observed Io(F)/Europa(R) occultations (video). Observed dimming before/after occultation (wings). Interpreted as dimming from thick atmosphere - PowerPoint PPT PresentationTRANSCRIPT
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Origin of StudyDegenhardt papers SAS2010, 2013, etc
Observed Io(F)/Europa(R) occultations (video)
Observed dimming before/after occultation (wings)
Interpreted as dimming from thick atmosphere (Jovian Extinction Events..JEE)
My investigation was for a decision whether to take data in 2014 (I decided not to)
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F&R in lineR in shadows
Eclipse
R
F
Occultation
R
F
Earth,F&R in perfect lineR likely notin shadows
Images converge Images do NOT converge
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Critical Problems
Pro-Astronomers see no thick atmosphere
Eclipses show no wings
Duplicate observations show null results
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Pro-Astronomers see no thick atmosphere
Telescopic searches w/big scopes and HST have never imaged atmosphere
Satellite probes near Jupiter see none
Satellites within 200km of Io saw/felt none, would literally have slowed down or burned up
See Mallama paper for details
#1. The Galileo Orbiter flew within a few hundred km of Io and Europa, yet spacecraft navigation experts found no atmospheric drag in the radio tracking data.#2. Images of Io and Europa taken by the Hubble Space Telescope reveal no atmospheres surrounding these satellites.#3.An examination of 50 Hubble images taken in ultraviolet, visible and infrared light when Io or Europa were transiting Jupiter show that there is no extinction due to an extended atmosphere.#4. An examination of 19 high quality PHEMU light curves, where Io or Europa occulted another satellite and in which data was taken well outside of the occultation itself, show no evidence for atmospheric extinction.#5. Decades of research conducted by world-class planetary scientists using all the available Earth-based and spacecraft data have conclusively shown that Io and Europa only possess extremely rarified exospheres whose particle densities are billions of times less than the Earth’s troposphere.
Advanced spectroscopic searches w/big scopes show only very faint (10^-9) atmospheres
Note: JEE references out of context)
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Extended JEE atmosphere not gravitationally feasible (Menke)
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Eclipses show no wings, but they should
Io atmosphere should cast shadow during eclipse, but not seen
No explanation
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Duplicate observations show null results
Others also see no wings, eg Gerhard Dengl (one of many)
Redding (in JEE group) had null observations explained adhoc -PDE, threshold (no physics, no predictive value)
s
20090901 occult
1000 sec
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Any ONE of the foregoing problems
is a fatal flaw for JEE
JEE does not exist if even ONE of these is true
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Photometric methods not used (eg, ref, linearity)
Inadequate documentation
Why video, why not CCD observations, no confirmations from am or pro
Lesser Problems
Overly defensive criticism of objections, many words, but non-rebuttal on physics
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But if not real, what was it?
Instrumental-potential for video non-linearity
Some other Jovian effect-hard to think of one
Analytical (eg., software)-Lots of data, but only LiMovie used
Obtained video data from Degenhardt of six events
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Technique:Convert video to JPGs
Use VirtualDub to select ~100 frames
Export/ImageSequence/..JPG
Paste into Maxim or other photometry prog, examine pixels, take averages, etc.
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Test:Did I reproduce wings?
VideoData LiMovie
VideoData JPGs MaximDL
YES
Wings NOT an artifact of processing
Test validates JPG/photometry methods
YES
Analytical problem?
Only thing left is a sensor/system problem..
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Video non-linearity concerns
Gamma used in video
Saturation and Roll-Off issues..
Video cams not tightly specified
Output=input ^ gamma Gamma=1 linear
Gamma applied in camera and/or LiMovie
Hidden algorithms, large/small scale features
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Actual saturation – 8bit=255 limit Linearity/roll-off not measured
Saturation and Roll-Off issues, cont
Unknown behavior approaching saturation (Roll-Off)
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Test: Linearity (when no sat)..Convert to JPGs, measure ratio intensities
Yes, sensor appears roughly linear
Dimming (wing)
Linear Video
Prediction Actual
(I+E)/Gany
Gany/Cal
(I+E)/Gany
Gany/Cal
0120UT 1.20 2.75 1.19 2.66
0200UT 1.20 2.75 1.07* 2.43
...
Can we tell whether system is generally linear?
If generally linear, then how about saturation or Roll-Off?
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What is happening in images?During occultation, images merge(During eclipse, do not merge)
Saturation MUST cause light lossand, ANY saturation shows out of control
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Can saturation cause wings?
Qualitative, features only
X
Saturation is plausible cause of wings
Software, slide one PSF over another, measure intensity
Can adjust saturation, gamma, spacing, noise, etc
Simulate saturation…
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Is saturation present in JEE video?
Convert to JPGs, inspect all objects, different times,
Jupiter-heavily saturated
Ganymede-seldom saturated
Io/Europa-increasing saturated pixels as merger/ occultation proceeds (Io+E>G)
Callisto (faintest) – never saturated
Yes, extensive Io/E saturation present in all JEE events (but not in Null observations)
Note:LiMovie poor tool for evaluating video, so used photometric methods
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Is the saturation sufficient?
Note-Io+Europa = 1.2xGanymede..use G. as surrogate
Multiply Ganymede pixels by 1.2, measure intensity: gives UNsaturated equiv. of Io+Europa
Apply saturation limits (tool in Maxim)
Remeasure intensity.. gives SATurated equiv of Io+Europa
Result—Saturation dims intensity 10-14%~same as wings
Hard to measure or calculate – lost information. Use surrogate:
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One last item..
Remember - some JEE group occultation videos show NO wings (PDE, etc given as cause)
But examining video data shows they were taken with longer fl scope-larger images, lower pixel values, no sat.
plus, other video observers do not see wings when properly using video
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Conclusions3 critical problems w/JEE: astronomic data, eclipses, other observers null results, plus
Saturation in video is shown sufficient to cause apparent dimming (JEE wings)
Root problem-insufficient attention to sensor, and failure to use photometric methods
Interpretation of data incorrect:there is no thick Io atmosphere
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Comments on “the debate”…Given the extraordinary claim, one must resolve, not bypass, all the major problems before taking JEE seriously
One can ALWAYS make arguments and find some data to support any view, but critical thinking (and Occam) is key in evaluating
Most of our debates are political debates about values: This is a scientific debate about evidence and physics. JEE is true or it is not
Continued debate or investigation after a problem is solved may be a sign of bad science.