A dual origin for Neptune's carbon monoxide?
Résumé
Heterodyne observations of Neptune have provided a measurement of the CO(2-1) line profile with a total bandpass of almost 8 GHz and a resolution of 4 MHz. The lineshape indicates that the CO mole fraction in Neptune's atmosphere is not uniform, but increases by a factor of ˜2 from the troposphere/lower stratosphere (0.5 ppm at p>20 mbar) to the upper stratosphere (1 ppm at p