The rigid body obliquity history of Mars.

The primary objective of this study is to explore the range of uncertainty in the obliquity history of Mars associated with the present uncertainty in the axial precession rate. A major result of the present analysis is the observation that, within the plausible range of present axial precession rate, a very wide range of obliquity histories are possible, including some which involve resonance passages within the relatively recent past. As a result, obliquities as high as 51.4°, or as low as 0.2°, may have occurred within the last 10-m.y.