Possible H2staggered+ ultraviolet spectrum of Jupiter

An ultraviolet spectral probe for a hydrogen-rich planetary atmosphere, such as that of Jupiter, is suggested, utilizing discrete lines in the H₂^staggered+ 2pπ_u?1sσ_g electronic transition. For the Jovian atmosphere, the dominant mechanism for exciting H₂⁺ to its 2pπ_u state appears to be photoexcitation, principally through absorption of the solar Lyman-α line. We estimate that the Jovian column emission rate of the H₂⁺ 2pπ_u(ν′ = 2, J′ = 1) →1sσ_g(ν″ = 18,J″ = 0) fluorescent line at 1236.6 Å is if1 photon cmsu-2 secsu-1; i.e., that if1 photon secsu-1 of this radiation would strike a 15-cm diameter mirror in a Jupiter fly-by at an impact parameter of 3 × 10⁵km. The critical role of corrections to the Born-Oppenheimer approximation in the use of an H₂⁺ probe is discussed.