若い太陽系外惑星β Pictoris bの急速な回転が観測されました
Ignas A G Snellen1, Bernhard R Brandl1, Remco J de Kok2
1Leiden Observatory, Leiden University, Postbus 9513, 2300 RA Leiden, The Netherlands.
Nature
|May 3, 2014
まとめ
外惑星ベータ・ピクトリスbの急速な回転は,近赤外線スペクトロスコーピーを用いて測定されました. この若いガス巨人は,太陽系のどの惑星よりも速く回転し,質量依存のスピン傾向に合わせて回転しています.
科学分野:
- 天文学 天文学
- エクソプラネット科学 エクソプラネット科学
- 惑星科学 惑星科学
背景:
- 惑星のスピンは,形成中の角運動量増加から発生しますが,詳細は不明です.
- 太陽系惑星は一般的に,水星と金星を除いて,質量とともにスピン速度が増加することを示しています.
研究 の 目的:
- 若いガス巨大系系外惑星ベータ・ピクトリス b.のスピン特性を調査する.
- ベータピクトリスbのスピンを太陽系惑星と形成モデルと比較する.
主な方法:
- ベータ・ピクトリス bの近赤外線スペクトル観測を10万分解像度で実施しました.
- 惑星の熱スペクトルにおける一酸化炭素からの吸収信号を分析した.
- 測定されたドップラーシフトとスペクトル線の回転拡大.
主要な成果:
- 炭素一酸化物信号に15 km/sのブルーシフトが観測され,円形の軌道が確認されました.
- 惑星のスペクトルラインプロファイルで,約25km/sの重要な回転拡大が検出されました.
- ベータ・ピクトリス bは,太陽系のどの惑星よりもかなり速く回転することを決定しました.
結論:
- Beta Pictoris bの急速な回転は,惑星の質量とともに回転速度が増加する傾向と一致しています.
- この発見は,惑星形成の過程における角運動量増積の理論を裏付けている.
- この研究は,系外惑星のスピン進化を理解するための重要なデータを提供します.
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