Scale Height Estimation of the Martian Atmosphere from CCD Observations at Opposition 2003
Abstract
Scale height of the Martian Atmosphere from CCD Observations at Opposition 2003 using the CarlZeiss double refractor of the Bosscha Observatory has been estimated by refering to a martian model atmosphere. We assume the hydrostatic equilibrium applies which gives the barometric equation for the pressure dependence of the Martian atmosphere with altitude (z). As an estimation to quantify the observational data we assume the gray LTE approximation holds to the upper boundary of the atmosphere, thereby reducing the Martian atmosphere to a simple gray LTE model. The resolution limit in our data only amounts to ~ 1 second of arc, which corresponds to a linear distance of 270 km on the Martian surface. The top of the atmosphere seen in the orange interference filter IF572 was estimated to ~ 342 km at λ = 572 nm, while in the blue filter IF421 the extend was 252 km at λ = 421 nm. Varying quantities smaller than this limit, cannot be estimated. Assuming the Hydrostatic Equilibrium and the gray LTE model for the atmosphere, the local temperature T with height (z) is found. The temperature varies as T(z) = Az + B, A = 0.0019, B = 249.4. The average Martian surface temperature is found T ~ 250 °K. The scale height H follows from the barometric equation. H ~ kT / mg, in the order of ~ 13 kilometres.
 Publication:

IAU Joint Discussion
 Pub Date:
 August 2006
 Bibcode:
 2006IAUJD..10E..39R