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恒星の不対称性による活発な星 ζ アンドロメダの太陽のようなダイナモがない
R M Roettenbacher1, J D Monnier1, H Korhonen2,3
1Department of Astronomy, University of Michigan, Ann Arbor, Michigan 48109, USA.
Nature
|May 5, 2016
まとめ
ζアンドロメダのスタースポット活動は グローバルな不対称性を明らかにし 太陽ダイナモ理論に挑戦しています 極点は観測されたが,より低い緯度のスポットは一時的なもので,独特の恒星の磁場行動を示している.
科学分野:
- 星の天体物理学
- マグネトヒドロダイナミック
- 外惑星科学
背景:
- 強い磁場によって引き起こされる 恒星表面の冷たい領域です
- 磁気活動は恒星の大気構造に影響し,質量と年齢の推定に影響します.
- スタースポットの北南分布は,恒星のダイナモを理解するための鍵です.
研究 の 目的:
- 磁気的に活発な星 ζ アンドロメダの星斑分布をイメージする.
- スタースポット活動の南北対称性を調べるため
- 太陽型ダイナモモデルの有効性を他の恒星にテストするために.
主な方法:
- 高解像度イメージングには,長期ベースライン赤外線インターフェロメトリーを使用した.
- 観測は2つの異なる時代で行われ スポット進化を追跡した.
- ドップラー画像の限界はインターフェロメトリーを用いて解決された.
主要な成果:
- 恒常的な暗黒の極点は,両時代の ζ アンドロメダで観察された.
- 低緯度の星斑の特徴は一時的であり,観測の間には持続しなかった.
- 太陽のような南北対称性が欠けていた.
結論:
- ζ アンドロメダは,太陽型ダイナモ理論と矛盾するグローバルな星斑パターンを示している.
- 観測された不対称性は 恒星の磁気活動を誘発する 代替メカニズムを示唆しています
- 極点は実際の特徴で 観測上の人工物ではなく 活発な恒星です
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