Observations Of H And D Densities And Escape Fluxes From The Upper Atmosphere
Of Mars With The Maven Iuvs Echelle Channel
J.T. Clarke, Center For Space Physics, Boston University, Boston Usa (Jclarke@Bu.Edu), M. Mayyasi Csp /
Bu, D. Bhattacharyya Univ Of Illinois Uc, Urbana Usa, J-Y Chaufray Latmos France, And The Maven
Iuvs Team Univ. Of Colorado Boulder Usa
From Late My 32 To Mid My 35.
Introduction: The History Of Water On Mars Is
Of Great Interest To Understand Terrestrial Planet Evolution. The Constituent Atoms Of Water Are Known To
Escape The Weak Martian Gravity Into Space, While
Heavier Water Molecules Remain In The Atmosphere.
A Key Indicator Of Water Loss Is The Ratio Of The Isotopes Deuterium To Hydrogen. The Lighter H Escapes
Faster Than D Leading To A Gradual Increase In The D/H
Ratio Of The Remaining Water. The Present D/H Ratio
Is Proportional To The Total Water Mars Has Lost In Its
Lifetime, But Deriving The Depth Of A Primordial Martian Ocean Requires Understanding The Physical Processes That Control Escape Today To Accurately Extrapolate Back In Time. Observations Of Uv Resonance
Line Emissions From H And D With The Maven And
Hubble Space Telescope (Hst) Missions Provide The
Key Atomic H And D Densities And Escape Rates.
Observations: H And D Atoms In The Martian
Upper Atmosphere Are Separately Measured By Resolving Their Uv Lyman-Α Emissions At High Spectral