Publication Date:
2010-12-15
Description:
The carbon-to-oxygen ratio (C/O) in a planet provides critical information about its primordial origins and subsequent evolution. A primordial C/O greater than 0.8 causes a carbide-dominated interior, as opposed to the silicate-dominated composition found on Earth; the atmosphere can also differ from those in the Solar System. The solar C/O is 0.54 (ref. 3). Here we report an analysis of dayside multi-wavelength photometry of the transiting hot-Jupiter WASP-12b (ref. 6) that reveals C/O 〉/= 1 in its atmosphere. The atmosphere is abundant in CO. It is depleted in water vapour and enhanced in methane, each by more than two orders of magnitude compared to a solar-abundance chemical-equilibrium model at the expected temperatures. We also find that the extremely irradiated atmosphere (T 〉 2,500 K) of WASP-12b lacks a prominent thermal inversion (or stratosphere) and has very efficient day-night energy circulation. The absence of a strong thermal inversion is in stark contrast to theoretical predictions for the most highly irradiated hot-Jupiter atmospheres.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Madhusudhan, Nikku -- Harrington, Joseph -- Stevenson, Kevin B -- Nymeyer, Sarah -- Campo, Christopher J -- Wheatley, Peter J -- Deming, Drake -- Blecic, Jasmina -- Hardy, Ryan A -- Lust, Nate B -- Anderson, David R -- Collier-Cameron, Andrew -- Britt, Christopher B T -- Bowman, William C -- Hebb, Leslie -- Hellier, Coel -- Maxted, Pierre F L -- Pollacco, Don -- West, Richard G -- England -- Nature. 2011 Jan 6;469(7328):64-7. doi: 10.1038/nature09602. Epub 2010 Dec 8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. nmadhu@mit.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21150901" target="_blank"〉PubMed〈/a〉
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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