Transcript Jovian Extinction Events

Jovian Extinction Events
JEE2014 Call for Observations
Modeling the Jovian dust field, moon atmospheres,
Europa water geysers, and Io’s Torus
2014 Annual IOTA Meeting, July 12-13, 2014 Baltimore, Maryland
(Filter), Color, Wavelength nm
(I) Infrared (not visible)
>750 nm
(R) Red
620-750 nm
Orange
590-620 nm
Yellow
570-590 nm
(V, G) Green
495-570 nm
(B) Blue
450-495 nm
Violet
380-450 nm
(UV)
Ultra Violet (not visible)
< 380 nm
White light spectrum of colors
Galileo probe found 600 nm particles around Io.
Our multicolor photometry of Io particles demonstrate the scattering effect.
Blue photons were significantly scattered while red photons were barely scattered.
Rayleigh and Mie scattering of photons
620-750 nm
Raleigh
590-620 nm
570-590 nm
Mie
495-570 nm
450-495 nm
380-450 nm
600 nm
PARTICLE
The Hubble Challenge
Question:
Why can’t I see the atmosphere surrounding Io when it transits Jupiter?
Answer:
Absolutely you can… you just have to do your homework!
The tiny but important details:
1) HST filter should sample 500 nm or shorter wavelength
photons (the shorter the better).
2) The use of a narrow band filter will only sample a narrow
band of the total represented scattered photons (meaning
the derived magnitude loss will never equal the
broadband magnitude loss).
3) Jupiter is an illuminated sphere with a constant intensity
gradient (it makes a horrible backdrop!). It is essential to
establish the trend of this background gradient trend to
normalize Io’s atmosphere transit data.
4) Europa’s atmosphere covers 44% of Jupiter during transit
making it impossible to derive a background trend.
5) Lots of pixel binning statistics increases S/N of JEE trends.
6) Io transits are ideal (if the appropriate wavelength light is
sampled).
U2YHA305T_D0M_PC1.TIF
Figure 2 Europa transit (Mallama, 2013)
Mallama (2013) Fig 2 of a Europa transit incorrectly identified the observed wavelength
as being 410 nm when in fact it was 544 nm where little if any extinction would be
detected (tiny detail #1 & #4).
No background trend was measured to normalize the derived “scanned luminosity” (tiny
detail #3 & #5).
Mallama (2013) incorrectly states that the JEE Campaign claims a trend should be visible
equivalent to the red line simulation when we have made no such claim for this Hubble
image, nor would we based on the above facts.
Rayleigh and Mie scattering of photons
620-750 nm
590-620 nm
U2YHA305T 544 nm
570-590 nm
495-570 nm
450-495 nm
380-450 nm
600 nm
PARTICLE
D0M_TIFF_DOCUMENT
= "U2YHA305T_D0M_PC1.TIF"
CENTER_FILTER_WAVELENGTH
= 0.5439 <micron>
BANDWIDTH
= 0.1228 <micron>
START_TIME
= 1995-10-04 T20:19:16
STOP_TIME
= 1995-10-04 T20:19:16
EXPOSURE_DURATION
= 0.2 <SECOND>
U3AP0308T_D0M_PC1.TIF
Figure 1 Io transit (Mallama, 2013)
Mallama (2013) Fig 1 of an Io transit incorrectly identified the observed wavelength as
being 555 nm when in fact it was 409 nm making this Hubble image an ideal candidate to
detect Io’s atmosphere. (tiny detail #1 & #6).
No background trend was measured to normalize the derived “scanned luminosity” (tiny
detail #3 & #5).
Mallama (2013) incorrectly states that the JEE Campaign claims a 15% extinction trend
should be visible equivalent to the red line simulation. HST used a very narrow bandwidth
filter for this image, so the expected detected extinction would realistically be a fraction of
the total broadband extinction (tiny detail #2).
Rayleigh and Mie scattering of photons
620-750 nm
590-620 nm
570-590 nm
495-570 nm
450-495 nm
U3AP0308T 409 nm
380-450 nm
600 nm
PARTICLE
D0M_TIFF_DOCUMENT
="U3AP0308T_D0M_PC1.TIF"
CENTER_FILTER_WAVELENGTH = 0.4088 <micron>
BANDWIDTH
= 0.0147 <micron>
START_TIME
= 1996-10-21T07:56:08
STOP_TIME
= 1996-10-21T07:56:16
EXPOSURE_DURATION
= 8. <SECOND>
background trend
Use background
to
normalize
Io atmosphere
16 Io radii width intensity profile
4 Io radii vertical binning
HST Image U3AP0308T_DOM_PC1
http://pds-rings.seti.org/vol/HSTUx_xxxx/HSTU0_6452/DATA/VISIT_03/
The IMCCE Challenge
Question:
Why can’t I see JEE trends in PHEMU Campaign mutual events?
Answer:
Absolutely you can… you just have to do your homework!
PHEMU IMCCE
Jovian mutual events
Rayleigh and Mie scattering of photons
620-750 nm
590-620 nm
570-590 nm
495-570 nm
450-495 nm
380-450 nm
600 nm
PARTICLE
PHEMU Tech notes recommend using a V, R, or I filter to observe Jovian
mutual events, with an emphasis on preferably using an R filter. This
would exclude sampling of the wavelengths with dominant JEE scattering.
There are datasets in the
IMCCE database that
demonstrate JEE trends.
Here are two random
examples fitted with JPL
Horizons ephemeris
PHEMU IMCCE
X Jovian mutual events
Rayleigh and Mie scattering of photons
620-750 nm
590-620 nm
X U2YHA305T 544 nm
570-590 nm
495-570 nm
450-495 nm
 U3AP0308T 409 nm
380-450 nm
600 nm
PARTICLE
SUMMARY
< 500 nm
dominate
JEE
detectability

Typical wing data outside of the mutual event submitted to IMCCE is usually 6 to 10
minutes in length. Typical JEE measurements are observed 10s of minutes outside the
mutual event.
Below highlights this omission of JEE data. The two lightcurves below are the exact
same event. The one on the left is with 6 minutes of wing data while the one on the
right is +/- 60 minutes of center of the mutual event.
Popular statement:
“The 1971 occultation of Beta Scorpii C by Io showed no extinction trend.
Therefore JEE can’t be real.”
30.00
Look closely at the length of this lightcurve prior to ingress. It is 30 seconds of time. The
extinction event would have begun 1260 seconds prior to ingress. 30 seconds is not enough
data to resolve the miniscule magnitude change in only 30 seconds of time. In 30 seconds
Beta Scorpii C only moved 0.2 Io radii. To detect a full extinction event you would have to
go out 9 or more radii. If you can find data from May 14, 1971 that starts a minimum of 21
minutes prior (this is where Beta Scorpii C was at 9 Io radii), and preferably 30 minutes
prior to get good wing data, then one can begin to look at this as a valid argument against
JEE. This event has insufficient data to make an argument for or against JEE.
Uninformed statement #1 about data from video:
“Video cannot provide accurate photometry.”
The Video Challenge
I have issued a challenge to others to name a photometric target to pit video
photometry against CCD photometry. To date no one has been willing to accept the
challenge (so my scientific viewpoint is that you do not have a valid argument
against video photometry if you aren’t willing to put it to the true test!). So I thought
to myself, what is the hardest target I could think of to challenge myself….
How about an exoplanet transit?!
Reply:
Video data (left) compared to CCD data (right)
Exoplanet transit HD189733 b
Ummm, I believe the answer for video is not only
YES, the quality difference speaks for itself.
Video data compared to calibrated CCD FITS are identical in trend for the same type JEE.
Types of noise in video and how to reduce them:
1) Systematic noise (removed by subtracting calibration frame)
a) Hot pixels
b) Thermal gradient across CCD chip
2) Random noise (removed by binning multiple data points into one)
a) Electronic readout noise frame to frame
b) Random thermal photons
c) Electronic noise from internal circuit (“snow”)
NTSC video produce 29.97 frames per second, PAL @ 25 frames per second at 8 bit resolution.
Using carefully placed background and measurements apertures in video photometry reduction
software such as LiMovie we obtain a background corrected photometry measurement for each
individual frame.
To significantly reduce scintillation and other noise contributions we then bin 10 seconds of data
into a single data point, i.e. 300 frames for NTSC or 250 frames for PAL into one point.
This yields 256 x 300 = 76,800 or > 16 bit statistical resolution, easily reaching 0.010 magnitude
stnd dev.
Video wins at photometry by the sheer volume of data
greatly leveraging the statistics to increase the S/N!
Uninformed statement #2 of video data:
“Video data cannot be calibrated.”
With 5 simple lines of code in an AVISynth
script I was able to subtract the calibration
frame (left) from the raw video (top left)
and create a new calibrated video (top
right).
(http://scottysmightymini.com/JEE/HowToCalibrateVideo.htm)
Sampling the intensity profile diagonally across the raw video shows the non-flat
response (mostly due to thermal heat on the CCD array).
After subtracting the calibration image from the raw video a test of the same region of
intensity shows the response has been flattened (and the previous slide shows the hot
pixels and defects were also removed).
Uninformed statement #3 about JEE video:
“The glare from Jupiter makes it impossible to get accurate photometry.”
We routinely reduce lunar occultations near the bright limb of our moon by carefully
configuring the background aperture to be tangent to the bright limb. The same applies with
Jupiter. Note the yellow measurement aperture right up against Jupiter measures zero ADU.
Uninformed statement #4 about video data:
“Gamma is the source of JEE trend in our lightcurves.”
We have multiple lightcurves of simultaneous observations with some cameras with
a gamma = 1 and another = 0.45, and both lightcurves demonstrate JEE dimming.
Uninformed statement #5 about video data:
“Camera response from merging intensities cause our JEE trends.”
Some will declare all
JEE invalid because a
portion of a single
video was saturated.
It is easy to see where
this lightcurve trend
goes flat as the merging
moons enter saturation.
We can toss out the
saturated portion of this
video and the JEE trend is
still prominent.
Saturated data is rare in
our data archives and is
discarded when identified.
Saturation theory as
source of extinction
trend doesn’t apply
here. This entire video
is not in saturation.
Note the peak from
Europa shrinks in size
relative to Io. This
coincided with Europa
passing behind Io line
of sight.
There is no mechanism by which a camera can randomly pick the moon in back to diminish its
intensity every time two moons merge intensities.
All of our extinction trends involving two moons have been identified as directly linked to the
moon behind another moon having a known atmosphere.
Combined photometry
80mm finderscope
Separate photometry
14” Meade
I
II
III
I+II
This event randomized every aspect of observation and reduction:
one large field of view to combine Io and Europa under one aperture and normalized to Ganymede
the other a small FOV to derive separate photometry of Io and Europa and then normalizing Europa by Io.
The geometry of the intensities on the CCDs are drastically different decoupling the JEE trend from Point Spread
Function or any other type of detector response of merging intensities.
Europa
A conjunction with no merging
moons (we have many of these).
2 independent observers
recorded the same JEE trend.
Inverting the lightcurve by
superimposing the extinction data
on JPL Horizon ephemeris shows
the trend fits in our approximate
20 Europa radii atmosphere.
Europa
Horizons ephemeris displaying path of probing objects behind Europa
Europa
Extinction data tracing out approximately 20 radii atmosphere
Jovian Extinction Event data trends are not reporting anything new.
JEE data models match published data for expected detection.
JEE observing merely presents an alternative observing modality.
If the source of JEE data was just noise or other camera response we
would not get the following consistent results from varied observers…
+
Schneider et al. “MUTUAL EVENT OBSERVATIONS OF
IO'S SODIUM CORONA (figure 7)”
Dividing the number of JEE scattered photons in the volume
by the column depth we have derived a first order
assumption (1 particle per 1 photon at about 3 radii):
Io column density of approximately 1.11E+11 cm-2 (+)
(Our detected density matches published densities)
How to best observe a JEE
Download predictions from JEE site:
This will give you the best way for planning when to start and stop an observing run.
Try to acquire up to 15 minutes (or longer) of data outside the anticipated time
frame of JEE data.
If you use JME predictions from OccultWatcher just observe +/- 5 times the
occultation duration of Io occulting a moon and +/- 10 times the occultation duration
when Europa is occulting a moon.
Exposure:
Pixel intensity for the target moon and all reference moons should be between 4080% of maximum intensity fill throughout the entire video.
If you camera does not have variable gain then you can use an aperture mask to dim
the moons of interest. (an aperture mask is preferred over defocusing for JEE work).
Wavelength:
If you don’t have filter capability observe broadband unfiltered.
If you can only observe with one filter use B.
If you can do two or more alternate between R-B, V-B, or I-B.
Camera type:
Use a video camera with as high a frame rate as possible.
Use a CCD camera with as high an image cadence rate as your system can provide.
For conjunctions (near-occultations) by
Io or Europa an estimated predicted
lightcurve is provided based on our
current JEE models.
For occultations by Io or Europa the
expected JEE trend outside the
occultation is displayed. The occultation
is removed (the gap in the lightcurve).
A PDF with detailed data is in each main folder:
Observe!
Predictions, results, and discussions available @:
http://scottysmightymini.com/JEE/
Yahoo Discussion Group JEE_Talk
[email protected]
References
AAVSO Alert Notice 464: Observers requested for Jovian Extinction Events (JEE2012), http://www.aavso.org/aavso-alert-notice-464
Arlot, J.-E., Thuillot, W.,Ruatti, C. and 116 coauthors observers of events: 2009, The PHEMU03 catalogue of observations of the
mutual phenomena of the Galilean satellites of Jupiter, Astronomy and Astrophysics, Volume 493, Issue 3, pp.1171-1182
Bohren, Craig F.; Huffman, Donald R. Absorption and scattering of light by small particles, New York: Wiley, 1983
Michael E. Brown & Richard E. Hill Discovery of an extended sodium atmosphere around Europa Nature 380, 229 - 231 (21 March
1996); doi:10.1038/380229a0 http://www.nature.com/nature/journal/v380/n6571/abs/380229a0.html
Burger, M.H. et al. “Mutual Event Observations of Io's Sodium Corona” (2001) http://www.iop.org/EJ/article/000437X/563/2/1063/52792.text.html
Burger, M.H. et al. “Europa’s neutral cloud: morphology and comparisons to Io Matthew H. Burger & Robert E. Johnson” Icarus 171
(2004) 557–560, http://www.igpp.ucla.edu/public/mkivelso/refs/PUBLICATIONS/burger%20neutral%20cldEuropa04.pdf
Degenhardt, S. Exoplanet HD189733 b transit results: http://var2.astro.cz/EN/tresca/transit-detail.php?id=1402007234
Degenhardt, S., “How to Calibrate Video” tutorial: http://scottysmightymini.com/JEE/HowToCalibrateVideo.htm
Degenhardt, S. et. al (2010), Io and Europa Atmosphere Detection through Jovian Mutual Events, The Society for Astronomical
Science: Proceedings for the 29th Annual Symposium on Telescope Science, p. 91-100
Degenhardt, S.M., “JEE2009-2014 Call for Observers” (2012) http://scottysmightymini.com/JEE/
Degenhardt, S.M. (2012), Yahoo Discussion Group JEE_Talk, [email protected]
References (cont.)
Degenhardt, S. M., Jovian Extinction Event Predictions and Reduction Methods, Author and developer: [email protected].
Observations and data from S. Aguirre, S. Degenhardt, M. Hoskinson, A. Scheck, B. Timerson , D. Clark , T. Redding, J. Talbot , JPL
Horizons On-Line
Degenhardt, S.M., “Io atmospheric extinction predictions for 2009 and 201o Jovian Mutual Events” (2009)
http://scottysmightymini.com/mutuals/Io_atm_extinct_predict2009_2010.htm
Christopher Go. Io shadow transit on Ganymede. Christopher Go, Cebu, Philippines, 2009.
E. Kardasis. The use of technology in capturing details on Jupiter's system with small telescopes. In European
Planetary Science Congress 2012, page 927, September 2012.
HST Image U3AP0308T_DOM_PC1.TIF of Europa transit: http://pds-rings.seti.org/vol/HSTUx_xxxx/HSTU0_6452/DATA/VISIT_03/
Krüger, Harald; Krivov, Alexander V.; Sremčević, Miodrag; Grün, Eberhard (2003). Impact-Generated Dust Clouds Surrounding the
Galilean Moons. Icarus, Volume 164, Issue 1, p. 170-187.
Kuznetsov, A.A. et. al, “Formation of zebra pattern in low-frequency Jovian radio emission” (2012), arXiv:1209.2923v1 [astro-ph.EP],
Planetary & Space Science
LiMovie 20030503 http://www005.upp.so-net.ne.jp/k_miyash/occ02/io_ganymede.html
Mallama, A., (2013), The Atmospheres of Io and Europa Are Transparent , The Strolling Astronomer , Volume 55, No. 4, Autumn 2013
References (cont.)
Miyashita, K., LiMovie, (2008) software to photometrically reduce AVIs. http://www005.upp.sonet.ne.jp/k_miyash/occ02/limovie_en.html
NSDC (Natural Satellites Data Center) database web address: http://www.imcce.fr/hosted_sites/saimirror/obsindhe.htm
O’Leary, B. 1971. “The occultation of Beta Scorpii C by Io and its implication”. Bulletin of the American Astronomical Society 3, 373.
PHEMU Observing Campaign Tech notes 3 , suggestion of V, R, I filter: http://www.imcce.fr/phemu/notes_tech/note03-en.php
Poddany S., Brat L., Pejcha O., New Astronomy 15 (2010), pp. 297-301,
Exoplanet Transit Database. Reduction and processing of the photometric data of exoplanet transits (arXiv:0909.2548v1)
Shadick, S. Exoplanet HD189733 b transit CCD camera results: http://var2.astro.cz/EN/tresca/transit-detail.php?id=1386701911
Schneider, N. M. et al., “The structure of Io's corona” (1991), ApJ, 368, 298
Solar System Dynamics Group, Horizons On-Line Ephemeris System, Author : [email protected],
http://ssd.jpl.nasa.gov/horizons.cgi
Warner, B., “Lightcurve Photometry and Analysis”, (2006), Springer Science+Media, Inc.