  This work presents theoretical studies which combine aspects of combustion
and explosion theory with exoplanetary atmospheric science. Super Earths could
possess a large amount of molecular hydrogen depending on disk, planetary and
stellar properties. Super Earths orbiting pre-main sequence-M-dwarf stars have
been suggested to possess large amounts of O2 produced abiotically via water
photolysis followed by hydrogen escape . If these two constituents were present
simultaneously, such large amounts of H2 and O2 can react via photochemistry to
form up to about 10 Earth oceans. In cases where photochemical removal is slow
so that O2 can indeed build up abiotically, the atmosphere could reach the
combustion explosion limit. Then, H2 and O2 react extremely quickly to form
water together with modest amounts of hydrogen peroxide. These processes set
constraints for H2 O2 atmospheric compositions in Super Earth atmospheres. Our
initial study of the gas-phase oxidation pathways for modest conditions with
Earth insolation and about a tenth of a percent of H2 suggests that H2 is
oxidized by O2 into H2O mostly via HOx and mixed HOx NOx catalyzed cycles.
Regarding other atmospheric species-pairs we find that CO,O2 mixtures could
attain explosive combustive levels on mini gas planets for mid range for the C
to O ratio in the equilibrium chemistry regime for p more than about 1bar.
Regarding CH4,O2 mixtures, a small number of modeled rocky planets assuming
Earth like atmospheres orbiting cooler stars could have compositions at or near
the explosive combustive level although more work is required to investigate
this issue.
