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Does a Dense Atmosphere ExistAround Io?

John Menke

June 2014

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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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Degenhardt observations(two observations of many)

X

Wings

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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)

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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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Typical video frame...

Ganymede

JupiterIo/Europa

Callisto

Event 20090901

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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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Typical frame near occultation

Io

Saturation

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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.