HR: 0800h
AN: P21A-0211    [Abstracts]
TI: Mars Orbit and Temperature: Why and When an Early wet Mars
AU: * Leubner, I H
EM: ileubner@crystallizationcon.com
AF: Rochester Institute for Fundamental Research, 35 Hillcrest Drive, Penfield, NY 14526 United States
AB: It is the intent of this work to present a model which predicts the time when liquid water was present on Mars. Experimental evidence indicates that liquid water existed on the planet Mars at 2.9 - 3.4 billion years ago, when Mars was considered to be cold. A model is presented that predicts Mars orbit and temperature variations based on solar radiative and non-radiative (solar wind) mass losses which affect planetary orbits. Mars orbits are predicted between 198 and 206 million Km at its formation five billion years ago vs. presently 228 million Km. The correlation between the solar (radiative) constant and planetary orbit estimates the transition from liquid water to ice (273K) to have occurred at about 3.4-3.8 billion years before the present time, which is in good agreement with the experimental estimate (2.9 - 3.4 Byr). Additional effects that are expected to extend higher Mars surface temperatures closer to the present are discussed. Examples are the planetary cooling rate after formation and effects due to hothouse gases, like carbon dioxide and water vapor, and effects dependent on variations in solar volume.
DE: 5400 PLANETOLOGY: SOLID SURFACE PLANETS
DE: 5407 Atmospheres--evolution
DE: 5416 Glaciation
DE: 5450 Orbital and rotational dynamics
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting