Planet with dense neon atmosphere and streams of CO2

[Czcibor]

Idea is a cold planet with dense atmosphere (10 atm) where human can survive, while a liquid carbon dioxide would be possible.

As the main component of atmosphere I think about neon, because it should not cause nitrogen narcosis:
http://en.wikipedia.org/wiki/Nitrogen_narcosis#Causes

Theoretically it is very popular element in universe (more than iron):
http://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements

How to make up a process which would make it plausible?

My idea so far:
-No gas giant in system to suck all volatiles.
-Planet migration inside after forming with plenty of volatiles.
-Higher planet mass than Earth.
-In order not to get a planet with 100% water surface, what about some mechanism to get rid of most of hydrogen. My only not violent idea is heavy UV light that would split water and let hydrogen escape. How to get it? (yes, I know short lived, massive star but wouldn't it send some hydrogen back when it blows its outer part at the end of its life?)

Any ideas?

 

[SteamKing]

Idea is a cold planet with dense atmosphere (10 atm) where human can survive, while a liquid carbon dioxide would be possible.

I'm not sure that humans would be too comfortable or could even survive if exposed to 10 atm. pressure for extended periods.

In the real world, most hyperbaric chambers used in therapy typically operate at 2.8 bar or below.

For extended periods of exposure to hyperbaric conditions, the concentration of oxygen which is being breathed must be carefully monitored to prevent too much oxygen from being absorbed by tissues. Even diving in such conditions here on Earth can cause a variety of adverse physiological conditions in the body due to exposure to elevated pressures for extended periods.

 

[Czcibor]

SteamKing:
Actually more challenging pressures were tested.
http://en.wikipedia.org/wiki/SEALAB#SEALAB_III

http://en.wikipedia.org/wiki/Saturation_diving
(record is 685.8 m, which would be roughly counting 68 atm)
Just the atmosphere should contain tiny amount of oxygen. (like 2%)

 

[SteamKing]

I'm not saying humans couldn't survive in high pressures for limited periods, but staying in such an environment for extended periods would be detrimental.

 

[Bystander]

mechanism to get rid of most of hydrogen

You're also trying to get rid of the nitrogen which is approximately the same cosmic abundance as neon, and heavier as far as gravitational retention. You might be able to work out some sort of accretion and crustal differentiation process history that mimics the Haber process and let's you get rid of the nitrogen as ammonia. Add a condition that this was a late forming/accreting planet, no ²⁶Al, so less heating and less release of oxygen from reduction of iron and other metal oxides, and you might make it credible.

 

[snorkack]

Venus has 3,2 bar nitrogen.
Earth is more massive and colder than Venus, yet has only 0,8 bar nitrogen.

How did Earth get rid of so much nitrogen?

 

[Czcibor]

You're also trying to get rid of the nitrogen which is approximately the same cosmic abundance as neon, and heavier as far as gravitational retention. You might be able to work out some sort of accretion and crustal differentiation process history that mimics the Haber process and let's you get rid of the nitrogen as ammonia. Add a condition that this was a late forming/accreting planet, no ²⁶Al, so less heating and less release of oxygen from reduction of iron and other metal oxides, and you might make it credible.

Damn, you're right.

Wild ideas:
-different ratio at start (do supernova produce elements in varied proportions or not specially?)
-some differentiation in space but I can't think of any plausible mechanism
-there is mild difference in mass, but huge difference in boiling point. Other small bodies in the system behind the snow line sucking all ammonia but unable to keep neon?

Venus has 3,2 bar nitrogen.
Earth is more massive and colder than Venus, yet has only 0,8 bar nitrogen.

How did Earth get rid of so much nitrogen?

I thought that any difference can either be explained by blowing away atmosphere on Earth after close encounter of the fourth kind ;) with Theia or by gasifying on Venus everything that could be affected by high temperature.

 

[snorkack]

Also: yes, nitrogen is fairly stable as a dinitrogen molecule, whereas neon is monoatomic. But still - dinitrogen, like dioxygen, can be split by sufficiently energetic UV or particle bombardment. Neon cannot. It can only be ionized, but so can nitrogen.

Does the exospheric escape of nitrogen takes place as mostly dinitrogen molecules (mass 28, heavier than neon) or as atomic nitrogen (mass 14, lighter than neon)?

 

[Czcibor]

You're also trying to get rid of the nitrogen which is approximately the same cosmic abundance as neon, and heavier as far as gravitational retention. You might be able to work out some sort of accretion and crustal differentiation process history that mimics the Haber process and let's you get rid of the nitrogen as ammonia. Add a condition that this was a late forming/accreting planet, no ²⁶Al, so less heating and less release of oxygen from reduction of iron and other metal oxides, and you might make it credible.

Anyway - less heating means that planet wasn't so much melted so more heavy elements remained on the surface, right?

 

[Bystander]

more heavy elements remained on the surface, right?

That would be the "hand-waving" argument, yes.

 

[Czcibor]

That would be the "hand-waving" argument, yes.

What do you mean? I thought that should be a consequence of your mentioned later forming of planet?

 

[Bystander]

should be a consequence

Yes. When I say "hand-waving," I mean that there aren't a whole lot of established facts/principles --- it's more an appeal to "intuition" based on what we currently know and suspect about planet formation and evolution.

 

[Czcibor]

Oh, I found one more, thing on wiki:

The argon found in Earth's atmosphere is 99.6% 40Ar; whereas the argon in the Sun – and presumably in the primordial material that condensed into the planets – is mostly 36Ar, with less than 15% of 40Ar. It follows that most of the terrestrial argon derives from potassium-40 that decayed into argon-40, which eventually escaped to the atmosphere.

http://en.wikipedia.org/wiki/Potassium-40

So the normal way to get noble gas is to have it produced locally through radioactive decay...

Neon's abundance in the universe is about 1 part in 750 and in the Sun and presumably in the proto-solar system nebula, about 1 part in 600. The Galileo spacecraft atmospheric entry probe found that even in the upper atmosphere of Jupiter, the abundance of neon is reduced (depleted) by about a factor of 10, to a level of 1 part in 6,000 by mass. This may indicate that even the ice-planetesimals which brought neon into Jupiter from the outer solar system, formed in a region which was too warm for them to have kept their neon (abundances of heavier inert gases on Jupiter are several times that found in the Sun).[26]

http://en.wikipedia.org/wiki/NeonSo:
1) Planet formed late after supernova explosion
2) It formed far away from its star
3) There was no gas giant in system, but there were a few planets to take other volatiles like water and ammonia
4) then it migrated inside (what the hell happened to other planets? ;) )
5) excess of water was split up by hydrolysis caused by UV or harder radiation, hydrogen escaped
6) source of UV disappeared but not in a explosion blowing hydrogen back (black hole from the supernova that consumed a star and provided so much energy to split nitrogen molecules and cause an atmospheric loss in which it would be more likely to leave)

So we end up with a troubled past, dormant black hole and a Neptune-like planet stripped to its core. Any ideas?

 

[snorkack]

So, what are the H2/He/Ne ratios of the 4 gas giants - Jupiter, Saturn, Uranus and Neptune, compared to Sun?

 

[Czcibor]

So, what are the H2/He/Ne ratios of the 4 gas giants - Jupiter, Saturn, Uranus and Neptune, compared to Sun?

No idea, I can't google data. I wonder whether its known.

Another study: maybe Jupiter has neon, but in deeper layers:
http://newscenter.berkeley.edu/2010/03/22/helium_rain/
(the amount that was found was considered as surprisingly low)

 

[snorkack]

How warm does a planet need to be to qualify as a hot Uranus?

Would an Uranus-like planet on orbit of Mars or Ceres qualify as even a warm Uranus? Or something else?

 

[Czcibor]

How warm does a planet need to be to qualify as a hot Uranus?

Would an Uranus-like planet on orbit of Mars or Ceres qualify as even a warm Uranus? Or something else?

Right... Hot Neptune

http://en.wikipedia.org/wiki/Hot_NeptuneAnyway, I started to wonder whether I was thinking in the right direction... Because I need just atmosphere which is in case of Earth 1/100000 of planet mass. Maybe I need a fully formed planet, stripped of all volatiles (whichever source of heat: radioactive, tidal heat, few direct crashes) that gets one more chance to get an atmosphere though a contact with a big gas cloud? (effectively as big event, instead of LHB we get a new wave of matter going through system) It could even make sense - there is a wave of star formation in whole cluster, and nearby a very heavy star is formed that ends up as supernova.

 

[snorkack]

Right... Hot Neptune

http://en.wikipedia.org/wiki/Hot_Neptune

No.
in an orbit close to its star (normally less than 1 AU).[2]

1. Hot Neptunes: A Key To Giant Planet Formation

Yours is more than 1 AU. That´s why it cannot be a "hot" Uranus or Neptune. Then what is it?
http://en.wikipedia.org/wiki/Hot_Neptune#cite_note-2