A volcano on Io

[ANDREA]

Andrea, if white, then more hottest than red...

Sure, as I posted before, up to 1500?°C have been measured in volcanic eruption, but IMHO the plume color depends not only on temperature but on materials too, and as I told burning sulphur emits blu light, not red. Remember that sulphur lights at about 450?°C.
Anyhow, if you can give an example of Io volcamic plume with red color I will admit you are right, otherwise...
Bye

Andrea

[Fenerit]

Look at this:

http://hubblesite.org/gallery/album/sol ... r1997021a/

Naturally here ALL is reddish! This can get a mistake; your evaluation about the sulphur's behaviour is right. Probabily this element to be eject as pyroclastic flow, rapidly cold by the external temperature and then burn by lapils.

[ANDREA]

Here are four snapshots of the latest model (for the Prometheus type), with its smooth shades of colors and transparencies. The red part is probably too strong. The color variation could be adjusted easily. I'll add more "jets" on that one. Or maybe I should try to make an ordinary 3ds mesh, instead of a mathematical model (?).

Cham, taking your above image as example, I made a try with PhotoShop, combining the color of your 3d image with this one, changing red to white, and this is the result:



IMHO it looks VERY close to the images we have seen up to now.
What is your opinion?
Bye

Andrea

[Fenerit]

I apologize with all: but what mean IMHO?

[selden]

In My Humble Opinion

It's one of many abbreviations frequently used in computer mediated communications. More are defined at
http://kb.iu.edu/data/adkc.html

[Fenerit]

Thank you, Selden.

[volcanopele]

The photoshop job ANDREA posted is VERY nice! If something like that can be created, it would be perfect.

Fenerit, keep in mind that the plume itself is not composed of incandescent lava, but is instead composed of dust and condensing sulfur and sulfur dioxide gas. The color image you posted is false color, and doesn't, IMHO, represent the color you would see if you were to actually observe these plumes from a distance. A slight reddish, maybe pink coloration maybe added close to the source to represent the glowing lava at the source (and reflected in the lower portion of the plume), but that's about it. The color shown in ANDREA's post is very close to what you would expect to see.

Cham, will this model be customizable? For example, if you could create a generic Prometheus-type plume and a generic Pele-type plume, can the user then edit an ssc file to place these where they want or are they more or less tied down to specific locations? If they are tied down, if you want, I can give you a list of plume locations from New Horizons.

[Fenerit]

I agree with your clarification. And what about the green color, that if I do not remember wrong, is emitted as "halo" by the sulphur when put on a Bunsen burner? Second question: how much an observer can see the blue color on the black blackground expecially when this it is not self-incandescence as a blue giant star? I'm sorry for this but I never seen the aurora boreal yet.

[t00fri]

In My Humble Opinion

It's one of many abbreviations frequently used in computer mediated communications. More are defined at
http://kb.iu.edu/data/adkc.html

Personally I think that the more of these acronyms people tend to use regularly, the closer their personality is to autistic

Bye Fridger

[bh]

In My Humble Opinion

It's one of many abbreviations frequently used in computer mediated communications. More are defined at
http://kb.iu.edu/data/adkc.html

Personally I think that the more of these acronyms people tend to use regularly, the closer their personality is to autistic ;-)

Bye Fridger

ROFL... :D

[chris]

The photoshop job ANDREA posted is VERY nice! If something like that can be created, it would be perfect.

Fenerit, keep in mind that the plume itself is not composed of incandescent lava, but is instead composed of dust and condensing sulfur and sulfur dioxide gas. The color image you posted is false color, and doesn't, IMHO, represent the color you would see if you were to actually observe these plumes from a distance. A slight reddish, maybe pink coloration maybe added close to the source to represent the glowing lava at the source (and reflected in the lower portion of the plume), but that's about it. The color shown in ANDREA's post is very close to what you would expect to see.

Should the plumes actually glow? I'm assuming that the plumes are visible due to reflected and scattered sunlight, not emitted light.

--Chris

[Fenerit]

If we think at how one can see on Io, we not escape in advance. Probably we should see the plume completly gray as gray is the black plume of a night fire illuminated by the full Moon as long as the Jupiter's luminosity being affect the result. In prossimity of the volcano we should be wrapped by a dense black smoke from which we do not see nothing, neither Jupiter itself. From an orbital point of view the matter should be even worse, as we can see for the spacecrafts, whose data are all unreal; when black and white when false-colored. The Cham's model red-blue was nice aestetically and this was suffice for me beyond the quest (right, we intend) on how should actually stands the things.

[buggs_moran]

This is all the further I got with my attempt from a few months ago (http://www.shatters.net/forum/viewtopic.php?t=10712). It is messy at the caldera and is all cmods, so it can be a bit choppy if your computer is slow... But the ejecta does move and it's pretty with a good card.

[Fenerit]

How they move?

[ANDREA]

This is all the further I got with my attempt from a few months ago (http://www.shatters.net/forum/viewtopic.php?t=10712). It is messy at the caldera and is all cmods, so it can be a bit choppy if your computer is slow... But the ejecta does move and it's pretty with a good card.

Buggs, can we test them?
From your images they look very interesting, but you added too the movement... wow!
Bye

Andrea

[Cham]

Cham, will this model be customizable? For example, if you could create a generic Prometheus-type plume and a generic Pele-type plume, can the user then edit an ssc file to place these where they want or are they more or less tied down to specific locations? If they are tied down, if you want, I can give you a list of plume locations from New Horizons.

The SSC could be edited by the user, of course. You'll be able to place any of those models at any location, even on another moon/planet, if you wish.

Even the colors and transparency effect can be edited easily in the CMOD files.

My only concerns for the moment is the appearence of the model. I'm really not satisfied with it. The symetric plume isn't very convincing, and the 3ds model is too simple (also too symetric). I'll have to work a lot more on them.

[buggs_moran]

How they move?

I put an invisible sphere at the lat/long of Prometheus. I then put invisible points every 10 degrees around the center and have a cmod ring rotating around (randomly). Give me a few days to refine what I had and I will put something up by this weekend.

[Fenerit]

Thanks a lot.

[volcanopele]

Here is the list of plumes to try (from New Horizons)

Code: Select all

Name                 Lat   Lon
Masubi (north)       -45    53
Masubi (south)       -49    58
Zal Patera            41    75
Amirani               21   115
Tvashtar Paterae      63   123
Prometheus             1   153
Culann Patera        -20   162
Illyrikon Regio      -70   170
Marduk               -28   210
Kurdalagon Patera    -50   218
Hephaestus Patera      2   290
N. Lerna Regio       -58   293


All these plumes are Promethean-type plumes reaching 75-100 km above the surface, particles landing 120-150 km from vent, except for Tvashtar, which is a Pele-type plume, reaching 400 km above the surface, with particles landing 445-720 km from the vent (though both Pele and Tvashtar are elongated in the N-S direction, with particles in the N-S direction landing 505-780 km from the vent. If you look at New Horizons observations of Tvashtar, you may notice lumps on the left and right hand side of the plume near the surface. What happens is that the larger dust particles in the plume land near the inner edge of the plume deposit, while smaller particles bounce off the surface and deposit on the outer edge of the plume deposit.

Here is a very crude graphic illustrating this:



Another property of plumes, that I am not sure can be addressed here, is that these plumes are forward-scattering, meaning the plumes are more visible when Io is visible as a crescent than when Io is visible as a full-disk. In fact, when visible as a full-disk, the plumes should be barely visible at all. As far as the glow, I am not sure, the color is right (what AURORA showed), but yeah, it shouldn't "glow" when sunlit.

Keep in mind, what you are looking at in visible light when Io is sunlit is NOT the sulfur and sulfur dioxide gas, but the dust entrained in the plume. The blue color is caused by the small-sized dust particles and the way these 10-50 nm sized particles scatter light.

[chris]

Another property of plumes, that I am not sure can be addressed here, is that these plumes are forward-scattering, meaning the plumes are more visible when Io is visible as a crescent than when Io is visible as a full-disk. In fact, when visible as a full-disk, the plumes should be barely visible at all. As far as the glow, I am not sure, the color is right (what AURORA showed), but yeah, it shouldn't "glow" when sunlit.

Keep in mind, what you are looking at in visible light when Io is sunlit is NOT the sulfur and sulfur dioxide gas, but the dust entrained in the plume. The blue color is caused by the small-sized dust particles and the way these 10-50 nm sized particles scatter light.

Thanks for all the information . . . I figured that the plumes were forward scattering. Celestia 1.5.0 already incorporates scattering effects when rendering planets with atmospheres, and I've been thinking other places that require scattering to be simulated: planetary rings, comet tails, volcanic plumes, and probably a few other places. I recently added support for point sprites to Celestia's cmod mesh file format and have been planning to use them for my own attempt at Ionian volcanos. It would be neat if scattering parameters could be specified for such particles--say, scattering coefficients for red, green, and blue, plus a phase function parameter. At 10-50 nm, the primary effect will be Rayleigh scattering, so would the sun take on a slight reddish hue when viewed through a plume?

--Chris