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Pluto System Speculation
Michael Hoopes
post Jul 18 2015, 02:31 AM
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Hi everyone- I'm new to this enterprise of Plutonian speculation; could someone direct me to a source that has decent information about its potential to have a magnetosphere?

I'm trying to make sense of that heart shape, as it extends, saddle-like, around the southern pole. Alternatively, could there a possible gravitational influence involving Charon, as I think the "heart" is bisected opposite of the tidally-locked, Charon-facing prime meridian? Could it be a reverse marker of the heart's proportion of sun-facing time, given its quite complex solar orbital attitude?

Or...are these just adorable newbie intuitions and/or possiible misconceptions that have already been addressed in this forum?

Thanks,

Mike
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dvandorn
post Jul 18 2015, 03:48 AM
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Kewl! Good to have a thread where we can speculate wildly. (ADMIN: With some restraint please. smile.gif)

I'm wondering why the CO ice is all in Tombaugh Regio on the lit side of the planet. What would cause CO ice to gather just there? Altitude? Temperature? Is there a liquid CO "aquifer" underneath that only wells up here?

Remember that the area is getting the most insolation it will get during the northern summer. Yes, it gets more direct sunlight when the sun is high over the equator, but only for half a Plutonian day, so overall right now, even at a lower angle of incidence, it's getting insolation continuously. So it's not exactly a cold sink.

I think you have to start getting your head wrapped around the 248-year cycle of seasons on Pluto. It spends more than 50 years in each season, and more than a century of continuous insolation on each pole. Cold sinks are going to appear in odd places, build up ices, and sublimate back off as this cycle continues. And I'm thinking that each set of seasons are unique -- topography changes, ice deposition occurs in different places due to vagaries of wind and even weather -- so major ice depositions might occur in different places in different years.

Maybe the CO ice is a remnant of a major deposition that occurred in the best cold sink available on what was then the dark side when a big exposure of CO ice sublimated relatively quickly from the southern hemisphere? And the other ices deposited at the time have preferentially sublimated since the northern hemisphere began its summer, leaving only the harder-to-sublimate CO ice? If so, what around here sublimates more easily than CO ice? And maybe the pitted surface at the southern edge of Sputnik Planum is an example of where those other ices puffed out, leaving holes in the CO ice?

Also -- hitting the various things that have been crossing my mind -- if Pluto is losing 5 tons of nitrogen an hour to space, over four billion years that amounts to nearly 163 and half trillion tons of nitrogen, if that's been a relatively consistent loss rate. How many tons of Pluto is left? How much of the original body has been blown away? And how much more of other lighter elements might have been lost earlier in Pluto's history?

And, to answer my own question, a quick search shows me that Pluto has an estimated mass of 13 quintillion tons. A quick calculation tells me that the amount of nitrogen lost (again assuming a consistent loss rate) is 1.25e-5 percent of Pluto's current mass. So, I guess maybe not so much... sounds like a heck of a lot, though!

-the other Doug


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surbiton
post Jul 18 2015, 03:56 AM
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MOD NOTE: Post moved from NH near encounter thread.


QUOTE (Mongo @ Jul 18 2015, 02:00 AM) *
Here are the top ten known KBOs with their diameters, with their major moons:

Pluto (2370 km) : Charon (1208 km)
Eris (2326 km) : Dysnomia (685 km)
Makemake (1430 km)
2007 OR10 (1280 km)
Haumea (1920 x 1540 x 990 km) : Hi'iaka (310 km), Namaka (170 km)
Quaoar (1110 km)
2002 MS4 (934 km)
Orcus (917 km) : Vanth (378 km)
Salicia (854 km) : Actaea (286 km)
2002 AW197 (768 km)

Half of the ten KBOs are known to have large satellites! The trend continues among smaller KBOs (allowing for the observational difficulties). Given how common large satellites are around KBOs, I have to think that they formed almost automatically as part of the main KBO formation, as mini-planetary systems. Pluto/Charon would be no exception, in my opinion.

Maybe their isolation in the outer reaches of the Solar System means that their formation was mostly left undisturbed, unlike the chaotic and energetic inner Solar System. So any growing satellites were left in orbit around their primary, without being perturbed away from, or into, them.


This rationale does make sense. Either:

1. All the moons were captured satellites later on;

or,

2. they more or less started like this and captured the Nix's of this world.

I am beginning to think #2.

Triton probably is an exception. But then Neptune is of another size altogether.
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dvandorn
post Jul 18 2015, 04:39 AM
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And, as usual, when playing with numbers, I got one wrong. Somehow I thought I had just read Pluto loses 5 tons of nitrogen an hour. I find I left off a couple of zeroes, it's 500 tons an hour.

So, I believe that makes the amount of nitrogen lost closer to 16.33 quadrillion tons over four billion years, and that's more like (if I'm figuring the scientific notation right, that was always hard for me to think in) 1.25e-3 percent of Pluto's present mass. More, but still a pretty small percentage. Nothing like the half of a percent that was estimated as little as ten years ago by those who anticipated a lot of gas loss from our favorite little KBO.

-the other Doug


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“The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
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MarsInMyLifetime
post Jul 18 2015, 06:43 AM
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Some years ago, part of the concern for mounting a near-term mission for Pluto was to intercept it before the atmosphere would freeze due to growing distance from the Sun, allegedly shutting down most cycles for the aphelion phase. I have not heard that concern mentioned for awhile, and had quietly reasoned that the concern was resolved with the timely launch of New Horizons. Yet I wonder whether the approaching aphelion season might indeed slow down the energy available for causing nitrogen loss. Thoughts on seasonal influence on gas loss (and how that affects projections about the planet's mass loss)?


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climber
post Jul 18 2015, 07:00 AM
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A bit hard to read and understand all points here. A simple question and sorry if it has been addressed. Is the Heart facing the opposite direction of Charon? If yes, can it helps explaining all CO is concentrated there? Thanks


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squirreltape
post Jul 18 2015, 11:01 AM
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At this very early stage in the data release I can't help but speculate about the lineations outlining the 'polygonal' terrain in yesterdays release (17 July). After Habukaz showed us the 'troughs' look like they have ridge-like structure, I was immediately reminded of Enceladus' Tiger Stripes in appearance. But, if the polygonal terrain is due in part to convective cells, then the edges with the troughs should be subducting, rather than venting.

If the edges of the polygons are subdudcting, could the darker, lumpy, blocky material that is associated with the troughs in many places be some kind of bouyant flotsam that has been transported and gathered in these ridges? It seems very strange that the polygon edges have what appears to be so much blocky material in them but not in the polygons proper. The Hi-rez imagery of this and so much more should clarify just what exactly is happenning in these areas.


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Fran Ontanaya
post Jul 18 2015, 11:36 AM
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Couldn't the simplest explanation for CO ice be that it's the area with the highest albedo? The difference between continuous airless insolation on a white surface and a black surface could be big.


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"I can easily see still in my mind’s-eye the beautiful clusters of these berries as they appeared to me..., when I came upon an undiscovered bed of them... – the rich clusters drooping in the shade there and bluing all the ground" -- Thoreau
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Sherbert
post Jul 18 2015, 12:12 PM
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QUOTE (dvandorn @ Jul 18 2015, 04:48 AM) *
I'm wondering why the CO ice is all in Tombaugh Regio on the lit side of the planet. What would cause CO ice to gather just there? Altitude? Temperature? Is there a liquid CO "aquifer" underneath that only wells up here?

Remember that the area is getting the most insolation it will get during the northern summer. Yes, it gets more direct sunlight when the sun is high over the equator, but only for half a Plutonian day, so overall right now, even at a lower angle of incidence, it's getting insolation continuously. So it's not exactly a cold sink.


Good idea that, maybe the subsurface "aquifer" of CO was penetrated by an impact and the pressure release, belched out a fluid slush of mainly CO. The breach would be sealed over with a "scab" of frozen CO. The raised, brighter, heart of the Tombaugh region comes to mind. An object about the size of the one that knocked out the dinosaurs, might do the trick.

EDIT:- Strangely enough that was about a once in a hundred million year event, the rough boundary mentioned for the timeframe of the most recent activity on Pluto.

Looking at DLD's second, enhanced colour image, the distribution of material across the top of the icecap "land bridge" suggests a west to east flow to the equatorial winds here. It looks like material has been blown out of the dark Whale region up onto the icecap. It appears to be quite sharply bounded on the Northern edge, only small amounts of material have reached the areas of the pits and even less reaching further North to the Sputnik Plain. Prevented by the prevailing North to South atmospheric flow, presumably. There is not enough detail in the Colour map to try and spot turbulence at the boundaries of these gas flow patterns, reflected in the surface colouring. Might be something to look out for in the Hi Res images.

The coloured area, the cone of the ice cream, appears to be considerably lower than Sputnik Plain. The slope between them is seen mainly as the pitted terrain. The pits, almost certainly sublimation features, seem to form on slopes, in roughly parallel rows, created by the different insolation of the slope as shadows move up and down the slope. Similar rows of pits can be seen at the tip of Tombaugh, referred to by JB I think as "nests". I think they look like golf bunkers, except they are considerably larger.
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alan
post Jul 18 2015, 03:57 PM
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IIRC during yesterday's press conference it was estimated the Nitrogen loss from Pluto would amount to a layer of 1000 - 9000 ft over the age of the solar system.
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alan
post Jul 18 2015, 04:10 PM
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QUOTE (surbiton @ Jul 17 2015, 10:56 PM) *
This rationale does make sense. Either:

1. All the moons were captured satellites later on;

or,

2. they more or less started like this and captured the Nix's of this world.

I am beginning to think #2.

Triton probably is an exception. But then Neptune is of another size altogether.


In the Kuiper belt satellites are common for the largest objects and for objects with low inclinations and eccentricities (called cold classical KBO's) From what I've read the largest objects have satellites because their gravity wells were large enough to retain material from collisions which formed satellites. Many of the satellites around the cold classicals are loosely bound which has is one piece of evidence that these objects formed at these locations rather than being scattered outward by Neptune. In simulations of collapsing clouds of solid particles two objects often form which may indicate that the cold classicals formed as binaries. As far as I know these simulations haven't yet been done for objects as large as Pluto.
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Sherbert
post Jul 18 2015, 10:04 PM
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So what is different about the Tombaugh Region that Carbon Monoxide ice collects only there in large amounts. This image shows the approximately real orientations of Charon and Pluto, and how the icecap relates to Charon.

http://www.nasa.gov/sites/default/files/th...d-charon-01.jpg

The tidal bulge in Pluto's atmosphere is on top of the Tombaugh region, creating a circular higher pressure zone. Elsewhere on Pluto the atmospheric pressure and temperature may not allow Carbon Monoxide to crystallise out as a solid, it remains as a gas in the atmosphere or is lost to space.

This postulated static high pressure zone must surely have an affect on atmospheric flow from hot hemisphere to cold. Would the flow be forced around the outside or through it, or would the higher pressure mass of gas start to spin?. Would warmer saturated "air" on reaching the higher pressure, deposit the various volatiles around its edge in the order dictated by their triple/freezing points, starting with the least volatile? Higher amounts of Methane ice on the Northern edge might be indicative of this. It is by no means the only explanation for Methane ice in this location. The climate is already looking anything but stagnant.

Earth's liquid oceans are intimately linked via a phase transition to the transport of latent heat around the planet in combination with heat transport in ocean currents. There is a single phase transition on Pluto, solid to gas and heat is transported around Pluto through latent heat exchange during deposition and sublimation of ices. The ices are just frozen atmosphere. Although at a much slower rate, heat can still travel through the surface ice, by convection and conduction.
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John Broughton
post Jul 19 2015, 04:33 AM
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QUOTE (dvandorn @ Jul 18 2015, 03:48 AM) *
I'm wondering why the CO ice is all in Tombaugh Regio on the lit side of the planet. What would cause CO ice to gather just there? Altitude? Temperature? Is there a liquid CO "aquifer" underneath that only wells up here?

It might not be a coincidence that Tombaugh Regio lies inside what l think is an impact basin roughly 800km wide.
Attached Image

Pluto is differentiated and likely to have layers of different volatiles at various depths. Here the impact penetrated deeper than anywhere else in the equatorial zone. Liquids filled the void, flowed south and carved a shoreline. Some of the nearby ropey terrain was eroded, leaving behind those craggy water-ice mountains surrounded by blocky debris. It's anyone's guess though, whether the surface CO deposits were laid down at that time or more recently.
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serpens
post Jul 19 2015, 05:09 AM
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It is a little sad that speculations on Pluto have been banished to an extraneous chit chat designation as opposed to a separate thread in the New Horizons segment. Regardless of data many of the forthcoming papers on the Pluto system will be informed speculation given the lack of definitive facts. For example, when did the Pluto Charon system form?

If as seems highly likely, Charon accreted from debris following a major collision we can safely state that this accretion would have occurred outside the Roche limit (around 3500 km for Pluto). The distance between Charon and Pluto now is 19,640 km but because they are tidal locked conservation if angular momentum means that Charon was once much closer. As separation increased there would initially have been major tectonic stresses gradually decreasing. Given Charon's lesser density and the fact that as the smaller body it would have become tidal locked before Pluto, the effects of tidal stresses on the surfaces of the two bodies would have been significantly different. If Charon was still reasonably close to Pluto tidal locking would have resulted in a tidal bulge that would collapse as distance increased resulting in something resembling a mountain in a moat. The tidal bulge for Pluto should gradually decrease until Pluto was also tidal locked without a residual bulge. Could Charon have received an external stimulus that resulted in the residual bulge being off centre? Could the final tidal locking been a recent event with residual tidal heat in the interior of Pluto?
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Paolo
post Jul 19 2015, 07:53 AM
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Mike Brown (aka @plutokiller) had a couple of interesting tweets yesterday on the subject of Pluto being geologically active:

QUOTE
In current hallway conversations with planetary scientists most are unconvinced by the evidence that "Pluto is geologically active"


QUOTE
covered in frost. frost redistribution is not the same as internal geological activity
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