Possible Large C/O Ratio on Several Transiting Exoplanets: Photochemical Consequences and Conceivable Origin

Details Possible Large C/O Ratio on Several Transiting Exoplanets: Photochemical Consequences and Conceivable Origin Possible Large C/O Ratio on Several Transiting Exoplanets: Photochemical Consequences and Conceivable Origin

Sep 2011

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011ess.....2.4004m&link_type=abstract

American Astronomical Society, ESS meeting #2, #40.04

Astronomy and Astrophysics

Astronomy

Scientific paper

Detailed analyses of transit and eclipse observations of extrasolar giant planets often suggest atmospheric compositions that are out of equilibrium and/or that contain a non-solar abundance of heavy elements. The departures from equilibrium are not surprising given the likely influence of transport-induced quenching of disequilibrium species on giant planets and given the large, photochemistry-inducing, ultraviolet flux incident on these close-in transiting exoplanets. What is surprising, however, is the nature of the departures from solar composition: CO typically appears to be more abundant than H2O on a wide variety of transiting exoplanets, ranging from the relatively cool GJ 436b to the warmer HD 189733b to the very hot WASP-12b. Large CO/H2O ratios are not expected from either thermochemical equilibrium or from disequilibrium chemistry in atmospheres with solar-like elemental ratios; however, they are expected for atmospheric C/O ratios that are close to 1. We use a photochemical and thermochemical kinetics and transport model to examine the influence of the atmospheric C/O ratio on the disequilibrium (and equilibrium) chemistry of the three aforementioned exoplanets. We find that the observable composition is extremely sensitive to the C/O ratio, which has some interesting consequences in relation to photochemistry and transit/eclipse observations. We discuss the implications for atmospheric composition and suggest ways in which the planets could have developed an enhanced C/O ratio during their formation and evolution. This work has been supported by the NASA Planetary Atmospheres program.

Affiliated with

Also associated with

No associations

Rating

Possible Large C/O Ratio on Several Transiting Exoplanets: Photochemical Consequences and Conceivable Origin 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 Possible Large C/O Ratio on Several Transiting Exoplanets: Photochemical Consequences and Conceivable Origin, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Possible Large C/O Ratio on Several Transiting Exoplanets: Photochemical Consequences and Conceivable Origin will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-833190