行星HD 189733 b是比木星还大的气态行星。研究已证实，该行星大气层中含有钠、一氧化碳、二氧化碳、水蒸气和甲烷。

Studies of HD 189733b, a hot gas giant that is larger than Jupiter, have confirmed that its atmosphere contains sodium, carbon monoxide, carbon dioxide, water vapour and methane.

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相反，TrES - 2b的大气层由气态钠、钾和三氧化钛这些可以吸收光线的化学物质组成，不过这也并不能为该行星极黑提供解释。

Instead, it has an atmosphere made up of chemicals such as vaporized sodium, potassium and gaseous titanium oxide, which absorb light, but that still does not explain the planet's extreme blackness.

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激光的频率被调节到能够点亮钠原子，这些钠原子是陨星在大气中很薄的一层里解体所留下的。

The laser beam is tuned to a frequency that lights up sodium atoms, which are left by disintegrating meteorites in a thin layer of the atmosphere.

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