Astronomy and Astrophysics – Astrophysics – Earth and Planetary Astrophysics
Scientific paper
2011-02-21
Astronomy and Astrophysics
Astrophysics
Earth and Planetary Astrophysics
Paper in press in Planetary & Space Science, special issue on Titan (2011), Conor Nixon and Ralph Lorenz, Guest Editors. 25 pa
Scientific paper
Earth and Titan are two planetary bodies formed far from each other. Nevertheless the chemical composition of their atmospheres exhibits common indications of being produced by the accretion, plus ulterior in-situ processing of cometary materials. This is remarkable because while the Earth formed in the inner part of the disk, presumably from the accretion of rocky planetesimals depleted in oxygen and exhibiting a chemical similitude with enstatite chondrites, Titan formed within Saturn's sub-nebula from oxygen- and volatile-rich bodies, called cometesimals. From a cosmochemical and astrobiological perspective the study of the H, C, N, and O isotopes on Earth and Titan could be the key to decipher the processes occurred in the early stages of formation of both planetary bodies. The main goal of this paper is to quantify the presumable ways of chemical evolution of both planetary bodies, in particular the abundance of CO and N2 in their early atmospheres. In order to do that the primeval atmospheres and evolution of Titan and Earth have been analyzed from a thermodynamic point of view. The most relevant chemical reactions involving these species and presumably important at their early stages are discussed. Then we have interpreted the results of this study in light of the results obtained by the Cassini-Huygens mission on these species and their isotopes. Given that H, C, N and O were preferentially depleted from inner disk materials that formed our planet, the observed similitude of their isotopic fractionation, and subsequent close evolution of Earth's and Titan's atmospheres points towards a cometary origin of Earth atmosphere. Consequently, our scenario also supports the key role of late veneers (comets and water-rich carbonaceous asteroids) enriching the volatile content of the Earth at the time of the Late Heavy Bombardment of terrestrial planets.
Martin-Torres Francisco J.
Trigo-Rodríguez Josep M.
No associations
LandOfFree
Clues on the importance of comets in the origin and evolution of the atmospheres of Titan and Earth does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Clues on the importance of comets in the origin and evolution of the atmospheres of Titan and Earth, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Clues on the importance of comets in the origin and evolution of the atmospheres of Titan and Earth will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-520495