My spec-bio project involves the idea of life evolving on a (Carbon?) Planet, rich with metals (Platinum, Chromium, Etc...) and pre-existing hydrocarbons. Basically life would have to evolve on an already "polluted" planet.
It is a 7 planet system orbiting a G1.5 star. In the early stages of system development planetary drift occurred bringing one of the gas giants to the innermost orbit. The main habitable world was spared from annihilation but was bombarded with enough material from the asteroid belt to balance out the elements allowing for an "Early Earth" like atmosphere and liquid water to collect. (Is this within the realm of possibility?)
Being that a gas giant is so close (~1 AU away) the homeworld experiences a lot of gravitational flux, causing an increase in volcanism and outgassing. This is my explanation for the availability of metals, and partly the composition of the atmosphere.
Through no particular reason I've decided on an atmospheric content of
- N2 ~68.4
- O2 ~ 21.3%
- CO2 ~ 3.25%
- N2O ~ 3%
- SO2 ~ 2%
- Ar ~ .98%
- Ne ~ 1.02%
Given that levels could replenished and maintained. Is there any other reason why this would not be a stable atmosphere?
Feel free to ask any questions if I left out any helpful information. I apologize for any apparent ignorance, i'm not a chemist or astronomer by any means.
Thank you to any and all who reply!