茶色矮星グリーゼ229Bの塵に満ちた大気です
C A Griffith1, R V Yelle, M S Marley
1Department of Physics and Astronomy, Northern Arizona University, Flagstaff, AZ 86011-6010, USA.
Science (New York, N.Y.)
|December 16, 1998
まとめ
ブラウン・ダワーフ・グリーゼ229B
科学分野:
- 天文学と天体物理学について
- エクソプラネット科学 エクソプラネット科学
- 大気科学 大気科学
背景:
- グリーゼ229Bのような茶色矮星は,独特の温度条件を持つ大気を持っています.
- これらの条件は,木星や低質量恒星とは異なり,氷の雲には暖かく,シリケート雲には冷たくなります.
- これにより,通常よりも深い大気観測が可能になります.
研究 の 目的:
- 茶色矮星グリーゼ229Bの大気組成を分析するために.
- その大気の深部で観測された微粒子の性質を特定するために.
- このユニークな茶色矮星で起きている大気中の過程を理解するために.
主な方法:
- グリーゼ229Bの0.85~1.0マイクロメートルのスペクトル解析.
- 観測された微粒子の光学特性を,既知の雲の組成 (氷やシリケート) と比較する.
- 観測されたスペクトルデータと恒星放射線に基づいた大気過程のモデリング.
主要な成果:
- Gliese 229B (10〜50バー) の奥深くに大気粒子が検出されました.
- これらの粒子は,氷とシリケート雲の両方と異なる光学特性を示す.
- 赤っぽい色は,惑星の平流圏のエアロゾールに似た有機組成を示唆しています.
- 粒子の質量分子は,光化学的起源と一致しています.
結論:
- Gliese 229Bの大気には,氷やシリケート雲ではなく,有機気溶液が含まれています.
- 恒星の放射線によって引き起こされる光化学的プロセスが,これらのエアロゾールの原因である可能性が高い.
- これらの発見は,惑星のような大気プロセスが茶色矮星で起こる可能性があることを示唆しています.
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