Exploring Mt Sharp - The Dunes - Part 1: Bagnold Dunes, Site 51-53, Sol 1172-1273, November 24, 2015-March 6, 2016 Options

[PaulH51]

Midnight Planets reporting that Curiosity moved approximately 46.2m SSE (161º) on Sol 1172. LINK Quick and Dirty L-NavCam using the 5 available frames (MS ICE), reduced ~10% to get within the UL limit

[Explorer1]

Wow, what an angle! Earth dunes can never get that steep, can they? A rare reminder of the lower gravity on the red planet...

[siravan]

Wow, what an angle! Earth dunes can never get that steep, can they? A rare reminder of the lower gravity on the red planet...

To the first approximation, the angle of repose is independent of the force of gravity (it cancels out). Now, this is not exactly true, as shown in this paper: http://onlinelibrary.wiley.com/doi/10.1029...003865/abstract . The actually measured the angle of repose of different materials in a "vomit comet" and saw some secondary effects.

[Arizona Dave]

To the first approximation, the angle of repose is independent of the force of gravity (it cancels out). Now, this is not exactly true, as shown in this paper: http://onlinelibrary.wiley.com/doi/10.1029...003865/abstract . The actually measured the angle of repose of different materials in a "vomit comet" and saw some secondary effects.

Interesting, that report's findings say that slopes should be less than on Earth...time for some good measurements.

I wonder if near Vacuum has an impact...the report didnt cover that.

[Gerald]

I wonder if near Vacuum has an impact...the report didnt cover that.

In the static case you may get some more clotting in a humid environment, as favored by higher pressure, due to thin branes of water coating grains.
In a dynamical scenario higher air pressure may cause aerodynamic effects, like the ground effect, or higher saltation of grains.

So atmospheric pressure and composition, especially humidity, should modify slopes and dynamical behaviour of the dunes.
On Mars, less ground effect and saltation would be expected, allowing for faster settling of grains, hence steeper slopes in dynamical situations.
On the other hand, static dunes may break down earlier on Mars, due to lack of sufficient humidity to contribute to clotting of grains.

Other factors are e.g. composition, surface roughness, size, or roundness of the grains, which may well differ between Earth and Mars.