APOD: Moon Io from Spacecraft Juno (2023 Oct 23)

[APOD Robot]

Moon Io from Spacecraft Juno

Explanation: There goes another one! Volcanoes on Jupiter's moon Io keep erupting. To investigate, NASA's robotic Juno spacecraft has begun a series of visits to this very strange moon. Io is about the size of Earth's moon, but because of gravitational flexing by Jupiter and other moons, Io's interior gets heated and its surface has become covered with volcanoes. The featured image is from last week's flyby, passing within 12,000 kilometers above the dangerously active world. The surface of Io is covered with sulfur and frozen sulfur dioxide, making it appear yellow, orange and brown. As hoped, Juno flew by just as a volcano was erupting -- with its faint plume visible near the top of the featured image. Studying Io's volcanoes and plumes helps humanity better understand how Jupiter's complex system of moons, rings, and auroras interact. Juno is scheduled to make two flybys of Io during the coming months that are almost 10 times closer: one in December and another in February 2024.

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[jks]

Are there two plumes near the top or am I seeing something else? (I clicked the image two times to zoom it for a closer look.)

[Ann]

I am a blue star girl. I am a blue star cluster girl. I am a blue nebula girl. I am a blue and/or spiral galaxy girl. But I am not a moon girl.

However, I am very much a color girl.

So, Io! We are going to have to look at a lot of color pictures of Io. The first Voyager 1 pictures of Io were very red. The Galileo images were color-corrected to look yellow-green:

Io by Voyager 1.

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Io through infrared, green and violet filters by spacecraft Galileo.

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Here is a full "roll-out" Io surface composite image from Voyager and Galileo:

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There is a large red ring on Io called Pillan Patera:

Io with red Pillan Patera by Galileo.

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Wikipedia wrote:

Io's largest plumes, Pele-type plumes, are created when sulfur and sulfur dioxide gas exsolve from erupting magma at volcanic vents or lava lakes, carrying silicate pyroclastic material with them.
...
Pele-type plumes form red (from short-chain sulfur) and black (from silicate pyroclastics) surface deposits, including large 1,000 kilometres (620 mi)-wide red rings, as seen at Pele.

In short, the large red ring is a volcanic deposit.

Ah yes, but there is some blue on Io, too! Namely, the volcanic plumes that rise from Io's surface when one of its volcanoes has an eruption!

https://upload.wikimedia.org/wikipedia/commons/e/e1/Galileo_July1999_MasubiPlume.jpg

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I guess that the blue color could be caused by gases being ionized by ultraviolet light from the Sun, as in the tails of some comets.

Charged gases detach from Comet Leonard's tail in December 2021. This image took top prize in the 2022 Astronomy Photographer of the Year competition. (Image credit: Gerald Rhemann, Royal Museums Greenwich, Astronomy Photographer of the Year 2022)

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But I find it a lot more likely that the blue color of the volcanic plumes of Io are just reflection nebulas, where sunlight is being scattered and refracted in dust particles. The same processes make Saturn's E ring, created by outflows from Enceladus, blue:

Far side of Saturn and the blue E ring. Credit: Cassini.

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Oh, and - I forgot! Today's APOD, featuring Io!

Io by Juno.

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How red it is!!! Is this "true color"? Would Io look like this if we could see it up close with our own eyes? Anyone?

Ann

[SpaceCadet]

Is the plume in the dark area at the top? Or is it somewhere else? Not sure what to look for exactly.

Thanks.

[Ann]

Are there two plumes near the top or am I seeing something else? (I clicked the image two times to zoom it for a closer look.)

I can only see one thing that might be a plume.

Ann

[Christian G.]

Io is one hell of a moon… and a volcanologist's paradise!

[orin stepanek]

Three lovely photos of Io!

[jks]

Are there two plumes near the top or am I seeing something else? (I clicked the image two times to zoom it for a closer look.)

I can only see one thing that might be a plume.


Ann

Yes, I think that you are correct. I mistook what is likely a surface feature that is in the Martian dusk for a "double plume". This feature is below and slightly to the left of the identified plume.

[AVAO]

Io by Juno.

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How red it is!!! Is this "true color"? Would Io look like this if we could see it up close with our own eyes? Anyone?

Ann

ThanX Ann

Global image of Io (true color) "This color mosaic uses the near-infrared, green and violet filters (slightly more than the visible range) of the spacecraft's camera and approximates what the human eye would see:"

Click to view full size image

The most interesting part of Io for me are "the burning fire -tubes and -balls", which to me looks not similar to a classic "earthlike" volcanism. ( http://www.gishbartimes.org/2010/08/io- ... t-two.html ) "Numerous lakes of molten sulfur have been found on Jupiter's moon Io. The wide color spectrum of the sulfur deposits gives the moon a colorful appearance. The lava flows, which extend over several hundred kilometers, are thought to consist primarily of sulfur or sulfur compounds." Wikipedia

Click to view full size image 1 or image 2

jac berne (flickr) NASA (Galileo) in "lava flow" from IR

Click to view full size image

Credit: Credit: NASA (Galileo) in "lava flow" from IR


If we see sulfur burning in the IR, it also needs enough oxygen. This means that Io colonisation by humans would be possible. It just smelled a bit bad outside the glass domes.

Jac


Star Trek's Vulcan Salute: Live Long and Prosper

[DRN]

Question for the experts:
Is there a dark plume in the lower right quadrant of this image of Io? It not far from below and right of center but looks like a black smear with a source from an apparent volcano with the dark, slightly curved cloud oriented toward the lower right of the image. Again, it resembles the plume off the northern edge except perhaps dark against the moon's surface.
It could be a dark surface feature but it is odd none the less. Thoughts?

[johnnydeep]

Ann conjectured above about a blue-looking plume on Io possibly being ionized by ultraviolet light from the Sun. But is the Sun's light intense enough to do that at the distance of Jupiter? Granted, ultraviolet light is still ultraviolet light (i.e, same frequency) even out there, but is there enough of it to cause enough ionization for us to be able to see it?

[Ann]

Io by Juno.

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How red it is!!! Is this "true color"? Would Io look like this if we could see it up close with our own eyes? Anyone?

Ann

Global image of Io (true color)
This color mosaic uses the near-infrared, green and violet filters (slightly more than the visible range) of the spacecraft's camera and approximates what the human eye would see.

Click to view full size image

[img]https://www.jpl.nasa.gov/images/pia0230 ... true-color


ThanX Ann

The most interesting part of Io for me are "the burning fire -tubes and -balls", which to me looks not similar to a classic "earthlike" volcanism. ( http://www.gishbartimes.org/2010/08/io- ... t-two.html )

Click to view full size image 1 or image 2

jac berne (flickr) NASA (Galileo) in "lava flow" from IR

Click to view full size image

Credit: Credit: NASA (Galileo) in "lava flow" from IR

Thanks, AVAO! Yes, I know that the yellow-green version of Io from Galileo is supposed to be very close to "true color". That's why I wondered why the Juno picture of Io is so red.

I also think that the "texture", the surface of Io, seems so different in the Juno image. For example, what is the large strange-looking feature that is front and center in the APOD?

Strange feature on Io.

Where is the strange Juno-image feature on Io? Maybe the dark feature near the top, to the upper right of the large red ring?

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Could it be that this part of Io is near Io's pole, and that it was not well photographed by Galileo? And that is why it looks so strange and unfamiliar here? And so red! I can't get over it.

Ann

[AVAO]

...
Could it be that this part of Io is near Io's pole, and that it was not well photographed by Galileo? And that is why it looks so strange and unfamiliar here? And so red! I can't get over it.

Ann

indeed it is the polar region. The question is why it is so dark. “Volcanic” activity does not only occur along the equator. I'm undecided as to whether the darker color could be due to there being a "magetic" relationship to the mother planet. If the incoming current affects Jupiter's polar region, the reverse should also be the case. But I can't really imagine that material is also transported or that surface material is chemically changed by physical influences.

Click to view full size image

Credit: NASA/John Spencer, Lowell Observatory and John Clarke, Boston University

[Ann]

...
Could it be that this part of Io is near Io's pole, and that it was not well photographed by Galileo? And that is why it looks so strange and unfamiliar here? And so red! I can't get over it.

Ann

indeed it is the polar region. The question is why it is so dark. “Volcanic” activity does not only occur along the equator. I'm undecided as to whether the darker color could be due to there being a "magetic" relationship to the mother planet. If the incoming current affects Jupiter's polar region, the reverse should also be the case. But I can't really imagine that material is also transported or that surface material is chemically changed by physical influences.

Click to view full size image

Credit: NASA/John Spencer, Lowell Observatory and John Clarke, Boston University

Thanks, AVAO! It is certainly interesting that the polar region of Io might be subject to magnetic onslaught from Jupiter, which might cause changes in Io locally and globally.

However, my guess is that the dark color of the feature near the pole of Io is not so remarkable in itself, because as you can see, there are other dark features on Io as well. There is one prominent dark spot immediately to the lower left of the large red ring:

Click to view full size image

So the dark regions could be a "natural" feature of the volcanism of Io. I'm still wondering about the red color of Io in the Juno image, though. What gives?

Ann

[bystander]

...
Oh, and - I forgot! Today's APOD, featuring Io!

Io by Juno.

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How red it is!!! Is this "true color"? Would Io look like this if we could see it up close with our own eyes? Anyone?
...

Another image, probably from the same data:

PIA25885: Juno Getting Closer to Jovian Moon Io
NASA / JPL-Caltech PhotoJournal | 2023 May 15

Data: NASA/JPL-Caltech/SwRI/MSSS; Processing: Kevin M. Gill

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And another, also with Ted Stryk

Io, with a bit of the night side in planetshine visible
Southwest Research Institute | Junocam | 2023 Oct 16

Data: NASA/JPL-Caltech/SwRI/MSSS; Processing: Ted Stryk

[johnnydeep]

Thanks, AVAO! Yes, I know that the yellow-green version of Io from Galileo is supposed to be very close to "true color". That's why I wondered why the Juno picture of Io is so red.

I also think that the "texture", the surface of Io, seems so different in the Juno image. For example, what is the large strange-looking feature that is front and center in the APOD?

APOD 23 October annotated.png

Strange feature on Io.

Click to view full size image

Where is the strange Juno-image feature on Io? Maybe the dark feature near the top, to the upper right of the large red ring?

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Could it be that this part of Io is near Io's pole, and that it was not well photographed by Galileo? And that is why it looks so strange and unfamiliar here? And so red! I can't get over it.

Ann

Here's where it maps to, just to make it painfully obvious to mmyself:

[VictorBorun]

to judge the colour, we can take this pic

and try saturation slider like this

there seem to be some pinkish regions and some greenish regions and that can be thought as a struggle of just two complimenting pigments: pink and green.
Both are in little quantities, so the surface is pretty grey.
And in places of balance the colour is grey.

But then again the places of balance seem rather yellow-ish grey, or olive, than just grey.
So maybe that yellow (sulfur?) is everywhere, as is the grey.
But pink vs green struggle is there too, making some places pinkish+yellowish (magenta tint) or greenish+yellowish (lime tint)

[Ann]

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Looking at this "roll-out" of the entire surface of Io, it does look as if regions near both poles are typically redder than than areas near most other latitudes. We can easily see that parts of Io are red anyway, due to (if I remember correctly) "short-chain" sulfur.

AVAO speculated that the onslaught of magnetism at Io's poles might lead to chemical changes. Perhaps we see a larger than average amount of short-chain sulfur near Io's poles?

Ann