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Title: THE EFFECTS OF SNOWLINES ON C/O IN PLANETARY ATMOSPHERES

Abstract

The C/O ratio is predicted to regulate the atmospheric chemistry in hot Jupiters. Recent observations suggest that some exoplanets, e.g., Wasp 12-b, have atmospheric C/O ratios substantially different from the solar value of 0.54. In this Letter, we present a mechanism that can produce such atmospheric deviations from the stellar C/O ratio. In protoplanetary disks, different snowlines of oxygen- and carbon-rich ices, especially water and carbon monoxide, will result in systematic variations in the C/O ratio both in the gas and in the condensed phases. In particular, between the H{sub 2}O and CO snowlines most oxygen is present in icy grains-the building blocks of planetary cores in the core accretion model-while most carbon remains in the gas phase. This region is coincidental with the giant-planet-forming zone for a range of observed protoplanetary disks. Based on standard core accretion models of planet formation, gas giants that sweep up most of their atmospheres from disk gas outside of the water snowline will have a C/O {approx} 1, while atmospheres significantly contaminated by evaporating planetesimals will have a stellar or substellar C/O when formed at the same disk radius. The overall metallicity will also depend on the atmosphere formation mechanism, and exoplanetary atmosphericmore » compositions may therefore provide constraints on where and how a specific planet formed.« less

Authors:
;  [1]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
Publication Date:
OSTI Identifier:
22047301
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 743; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; ATMOSPHERIC CHEMISTRY; CARBON; CARBON MONOXIDE; ICE; JUPITER PLANET; OXYGEN; PLANETARY ATMOSPHERES; PLANET-SYSTEM ACCRETION; PROTOPLANETS; SATELLITE ATMOSPHERES; VARIATIONS; WATER; ZONES

Citation Formats

Oeberg, Karin I, Murray-Clay, Ruth, and Bergin, Edwin A., E-mail: koberg@cfa.harvard.edu. THE EFFECTS OF SNOWLINES ON C/O IN PLANETARY ATMOSPHERES. United States: N. p., 2011. Web. doi:10.1088/2041-8205/743/1/L16.
Oeberg, Karin I, Murray-Clay, Ruth, & Bergin, Edwin A., E-mail: koberg@cfa.harvard.edu. THE EFFECTS OF SNOWLINES ON C/O IN PLANETARY ATMOSPHERES. United States. https://doi.org/10.1088/2041-8205/743/1/L16
Oeberg, Karin I, Murray-Clay, Ruth, and Bergin, Edwin A., E-mail: koberg@cfa.harvard.edu. Sat . "THE EFFECTS OF SNOWLINES ON C/O IN PLANETARY ATMOSPHERES". United States. https://doi.org/10.1088/2041-8205/743/1/L16.
@article{osti_22047301,
title = {THE EFFECTS OF SNOWLINES ON C/O IN PLANETARY ATMOSPHERES},
author = {Oeberg, Karin I and Murray-Clay, Ruth and Bergin, Edwin A., E-mail: koberg@cfa.harvard.edu},
abstractNote = {The C/O ratio is predicted to regulate the atmospheric chemistry in hot Jupiters. Recent observations suggest that some exoplanets, e.g., Wasp 12-b, have atmospheric C/O ratios substantially different from the solar value of 0.54. In this Letter, we present a mechanism that can produce such atmospheric deviations from the stellar C/O ratio. In protoplanetary disks, different snowlines of oxygen- and carbon-rich ices, especially water and carbon monoxide, will result in systematic variations in the C/O ratio both in the gas and in the condensed phases. In particular, between the H{sub 2}O and CO snowlines most oxygen is present in icy grains-the building blocks of planetary cores in the core accretion model-while most carbon remains in the gas phase. This region is coincidental with the giant-planet-forming zone for a range of observed protoplanetary disks. Based on standard core accretion models of planet formation, gas giants that sweep up most of their atmospheres from disk gas outside of the water snowline will have a C/O {approx} 1, while atmospheres significantly contaminated by evaporating planetesimals will have a stellar or substellar C/O when formed at the same disk radius. The overall metallicity will also depend on the atmosphere formation mechanism, and exoplanetary atmospheric compositions may therefore provide constraints on where and how a specific planet formed.},
doi = {10.1088/2041-8205/743/1/L16},
url = {https://www.osti.gov/biblio/22047301}, journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 743,
place = {United States},
year = {2011},
month = {12}
}