熱い海王星質量系外惑星の広大大気からのスペクトル分解のヘリウム吸収
R Allart1, V Bourrier2, C Lovis2
1Observatoire Astronomique de l'Université de Genève, Université de Genève, Chemin des Maillettes 51, 1290 Versoix, Switzerland. romain.allart@unige.ch.
Science (New York, N.Y.)
|December 8, 2018
まとめ
研究者らは,HAT-P-11b系外惑星の大気中に中性ヘリウムを発見し,その大気圏の拡大と質量損失を明らかにした. この突破は 恒星間吸収の課題にもかかわらず エクソプラネットの大気の研究に役立ちます
科学分野:
- 外惑星科学
- 大気物理学
- 天体物理学
背景:
- 近い系外惑星は 恒星の加熱により 膨張した大気を形成します
- 中性水素のような重要なスペクトルシグネチャの 恒星間媒体の吸収により,これらの拡張された大気の観測は困難である.
研究 の 目的:
- 熱い海王星質量系外惑星 HAT-P-11b の大気圏を検出し特徴づけること
- 星間吸収によって引き起こされる 観測上の課題を克服するために
主な方法:
- 地上からの高解像度観測で ニュートラルヘリウムの近赤外線三重体を検出しました
- 観測された吸収スペクトルを解釈するために3次元シミュレーションを使用した.
主要な成果:
- HAT-P-11bの大気中の中性ヘリウム特性を2回の通過で発見しました.
- 外惑星の大気は5つの惑星半径を超えて広がり,大きなスケールの高さを示しています.
- ヘリウムの質量損失率は1秒あたり3 × 10 ^ 5グラム以下と推定される.
結論:
- ニュートラルヘリウムの検出は,系外惑星の大気への新しい観測窓を提供します.
- 証拠によると,高空の風 (約. 3 km/s) が存在し,昼側から夜側へ流れます.
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