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近くの低質量恒星を通過する超地球
David Charbonneau1, Zachory K Berta, Jonathan Irwin
1Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA. dcharbonneau@cfa.harvard.edu
Nature
|December 18, 2009
まとめ
超地球型系外惑星GJ 1214bは,主に水で構成されている可能性がある. その大気は,おそらく脱出しているものの,惑星のため研究に適しています.
科学分野:
- 外惑星科学とは,外惑星科学のこと.
- 惑星の大気圏
- アストロケミストリー アストロケミストリー
背景:
- 通過する太陽系外惑星の検出は,大気組成の研究を可能にします.
- 特徴は,惑星対恒星半径比が大きい近くの通過系に限られている.
- 質量 (1.9-10地球の質量) で定義される超地球は,新型の系外惑星のクラスを表しています.
研究 の 目的:
- 通過する超地球GJ 1214b.の大量組成を制限するために.
- GJ 1214b.の大気研究の可能性を評価する.
- GJ 1214b.の大気の進化を調査する.
主な方法:
- 通過する惑星GJ 1214bの観測.
- 惑星の質量 (6.55地球の質量) と半径 (2.68地球の半径) の分析.
- 質量と半径に基づいて惑星の組成のモデリング.
主要な成果:
- GJ 1214bの質量と半径は,主に水からなる組成と一致しています.
- 惑星は,質量の0.05%しか構成しない水素ヘリウム封筒を有しています.
- 大気は水力力学的に脱出している可能性があり,歴史的な進化が顕著であることを示しています.
結論:
- GJ 1214bは,地球と氷の巨人の間の中間惑星を表しています.
- 惑星の組成は,かなりの水分を含有することを示唆しています.
- その近さと特徴により,GJ 1214bは現在の大気の研究に適しています.
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