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エクソプラネットHD 209458bbの軌道運動,絶対質量,高空風について
Ignas A G Snellen1, Remco J de Kok, Ernst J W de Mooij
1Leiden Observatory, Leiden University, Postbus 9513, 2300 RA Leiden, The Netherlands. snellen@strw.leidenuniv.nl
Nature
|June 26, 2010
まとめ
研究者らは,太陽系外惑星HD 209458bの質量を,その通過中にスペクトロスコピーを用いて測定した. 彼らは大気中の一酸化炭素を検出し,風を明らかにし,その質量が0.64 +/- 0.09の木星質量であることを確認しました.
科学分野:
- エクソプラネット科学 エクソプラネット科学
- 大気物理学 大気物理学
- 星の天文学 星の天文学
背景:
- 太陽系外惑星の質量の推定は,通常,放射線速度による宿主星の特徴に依拠しています.
- 惑星の軌道速度を決定することは,重力法則を用いた正確な質量計算に不可欠です.
- 以前の方法では,系外惑星の大気動態の直接測定ができなかった.
研究 の 目的:
- 通過中の系外惑星HD 209458bの大気のスペクトル学的特徴を特定する.
- HD 209458bの軌道速度を測定することによって,その質量を決定します.
- HD 209458b.上の大気動力学,特に風のパターンを調査するために.
主な方法:
- エキゾープラネットの通過中の高分散地面用スペクトロスコーピー.
- 惑星の大気中の一酸化炭素吸収線における波長変化の分析.
- 質量決定のためのニュートンの重力法則の適用.
主要な成果:
- 炭素一酸化物の吸収線における波長の大きな変化が観測され,惑星の放射速度の変化を示した.
- 主星の質量は1.00 +/- 0.22 M (太陽) と決定されました.
- 外惑星HD 209458bの質量は,0.64 +/- 0.09 M ((Jup)) と計算されました.
- 炭素一酸化物信号のブルーシフトは約2km/sは,風が昼側から夜側へ流れていることを示唆しています.
- 上層大気中の一酸化炭素の混合比率は (1-3) x 10(-3) と見積もられた.
結論:
- この研究では,直接の大気観測を通じて,太陽系外惑星HD 209458bの質量を決定することに成功しました.
- HD 209458bの強い大気風の証拠が発見され,放射された昼側から夜側へと流れていた.
- この発見は,系外惑星の大気組成と動態についての洞察を提供します.
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