Program: GN-2011B-Q-1

We will take high resolution (up to R ~ 18,000) GNIRS spectra of Jupiter, Uranus and Neptune in the methane transparency windows at 1.55 and 2 microns. Using our radiative transfer models and the latest laboratory spectral line data for methane at low temperatures we will measure the strength of the CH3D bands in these two windows and compare with CH4 lines to measure the D:H ratio in methane. We will compare the results with the predictions of chemical and dynamical models of the early solar system. D/H is an indicator of the location in the solar system at which material formed and so can be used to test current ideas on the early solar system that suggest significant migration of the giant planets to their current orbits. The observations will also enable a better determination of the protosolar D/H ratio.