Kinetic inhibition of CO and N2 reduction in circumplanetary nebulae - Implications for satellite composition

In constrast to the solar nebula, the conversion of CO to CH/sub 4/ and of N/sub 2/ to NH/sub 3/ in the circumplanetary nebulae of the Jovian planets is fast enough relative to radial mixing and nebula cooling rates that CO and N/sub 2/ are minor constituents in the circumplanetary nebulae. Thus, although the Jovian planets may have accreted carbon and nitrogen from the solar nebula mainly in the form of CO and N/sub 2/, these species were then reprocessed within the circumplanetary nebulae to form mainly CH/sub 4/ and NH/sub 3/. Satellites of the Jovian planets which accreted in sufficiently cool parts of their circumplanetary nebulae are therefore predicted to retain large amounts of NH/sub 3/ and CH/sub 4/ in the form of clathrate hydrates and also very small but chemical important amounts of HCN.