太陽系外惑星の大気の急速な加熱
Gregory Laughlin1, Drake Deming, Jonathan Langton
1UCO/Lick Observatory, University of California, Santa Cruz, California 95064, USA. laughlin@ucolick.org
Nature
|January 30, 2009
まとめ
天文学者は,熱い木星の系外惑星であるHD 80606bを,その恒星に最も接近した際に観測した. 惑星 惑星の惑星
科学分野:
- エクソプラネット科学 エクソプラネット科学
- 赤外線天文学の天文学
- 惑星の大気圏
背景:
- ホット・ジュピター系外惑星は潮的に同期しており,恒星面の恒星半球を持っている.
- 偏心軌道を持つ惑星は,地球温暖化の直接的な測定を可能にします.
- HD 80606bは極めて偏心的な軌道をしており,潮の加熱効果を研究するのに理想的です.
研究 の 目的:
- 恒星周辺を通過する際にHD 80606bの熱放射を測定するために.
- 惑星の大気特性を制限し,潮による温暖化率を制限するためです.
- 極端な放射線下にある系外惑星の大気の動態を調査する.
主な方法:
- periastron周辺の30時間の間隔の間に8ミクロムの光度測定観測を行いました.
- 明るさと温度の変化の分析.
- 軌道の傾きと惑星の質量を決定するために二次日食の検出.
主要な成果:
- 6時間間にわたって明るさ温度が ~800 K から ~1500 K まで急速に上昇した.
- 2次日食を検知し,軌道傾きが90度近くであることを示唆しました.
- 8ミクロムの光球で約4.5時間の放射時間定数を測定した.
結論:
- HD 80606bは,その離心軌道により,地球温暖化が著しく発生しています.
- 惑星の放射時間常数は,地球の平流圏値よりもはるかに短くなります.
- これらの発見は,高度に照射された系外惑星の大気動態についての洞察を提供します.
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