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Analysis of the chemical signature of gas giant exoplanet WASP 12 b reveals it to have a highly unusual makeup of more carbon than oxygen, with implications for the types of rocky planets that may be out there. Christopher Intagliata reports
通過對太陽系外行星（編號：WASP-12B）的氣體化學特征分析顯示：其氣體構成中碳含量遠超過氧含量，表明該處可能存在此種類型的巖石結構行星。
Imagine climbing diamond mountains, or hiking around the graphite shores of a lake of tar. Sound a little sci-fi? Well a new discovery suggests planets like that might be out there—planets littered with carbon minerals, instead of the oxygen-rich silicates, like quartz, that cover the Earth. Because astronomers have found the first carbon-rich exoplanet, with more carbon than oxygen in its atmosphere—instead of the 1 to 2 carbon to oxygen ratio found in our solar system.
The exoplanet, called WASP 12 b, is a gas giant, like Jupiter. By taking the spectrum of heat radiating from the planet, the researchers found that the planet's atmosphere was loaded with carbon, in the form of carbon monoxide and methane. The study appears in the journal Nature. [Nikku Madhusudhan et al., "A high C/O ratio and weak thermal inversion in the atmosphere of exoplanet WASP-12b"]
The finding suggests one commonly accepted model of planetary formation, where icy chunks glom into a core, wouldn't work here.
Instead the core may have formed from carbon-rich fragments, like tar. But more than that, this unusual planet is more proof of the diversity of the universe—and it makes those dreams of diamond planets a tiny bit more plausible.
—Christopher Intagliata
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