... stars

See http://www.obspm.fr/encycl/encycl.html for an update

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... Rosenqvist

See also the commentary to this work done by Kasting (1995).

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...$\mbox{$P_{{\rm O}_{2}}$ } \approx 0.5$ mbar 

The factor 2 difference may be attributed to the role of ${\rm CO}_{2}$ in the association reactions which is taken into account in our model. Indeed, in the case A (current Mars) the introduction of this effect leads to a decrease of the ${\rm O}_{2}$ column density from $5.3\times 10^{20}$ to $2.5\times 10^{20}$ cm^-2.

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... stars

The case of young stars with high UV (T-Tauri phase) and its impact on inorganic photochemistry has been studied by Canuto et al. (1982). However, this UV/EUV excess cannot interact with the primitive atmosphere because 1) the stellar phase involved is too short (<10⁵ yr, Bontemps, private communication); 2) UV excess is produced by dust accreting on the star and the same dust absorbs the UV in the planetary disk.

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