On the ortho-para equilibrium of H2 in the atmospheres of the Jovian planets

The ratio for the equivalent widths for the unsaturated H₂ quadrupole transitions observed in the Jovian planets is calculated and compared with a large number of observations. The comparison indicates that equilibrium hydrogen may be present in Jupiter and Saturn, while Uranus and Nepture exhibit ratios not in accord with equilibrium hydrogen. Observations which can differentiate among the possible states of H₂ are proposed.