Carbon-rich planet formation in a solar composition disk

Journal Article · Sun Apr 20 04:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/785/2/125· OSTI ID:22357082

Ali-Dib, Mohamad; Mousis, Olivier; Petit, Jean-Marc ^[1]

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1. Université de Franche-Comté, Institut UTINAM, CNRS/INSU, UMR 6213, Observatoire de Besançon, BP 1615, F-25010 Besançon Cedex (France)

The C to O ratio is a crucial determinant of the chemical properties of planets. The recent observation of WASP 12b, a giant planet with a C/O value larger than that estimated for its host star, poses a conundrum for understanding the origin of this elemental ratio in any given planetary system. In this paper, we propose a mechanism for enhancing the value of C/O in the disk through the transport and distribution of volatiles. We construct a model that computes the abundances of major C- and O-bearing volatiles under the influence of gas drag, sublimation, vapor diffusion, condensation, and coagulation in a multi-iceline 1+1D protoplanetary disk. We find a gradual depletion in water and carbon monoxide vapors inside the water's iceline, with carbon monoxide depleting slower than water. This effect increases the gaseous C/O and decreases the C/H ratio in this region to values similar to those found in WASP 12b's day side atmosphere. Giant planets whose envelopes were accreted inside the water's iceline should then display C/O values larger than those of their parent stars, making them members of the class of so-called carbon-rich planets.

• OSTI ID: 22357082
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 785; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
CARBON
DIFFUSION
DISTRIBUTION
PLANETS
PROTOPLANETS
SATELLITE ATMOSPHERES
SATELLITES
STARS
SUBLIMATION
WATER