近く に ある 巨大 惑星 は,その 星 に 飲み込ま れる こと から 逃れ ます
Marc Hon1, Daniel Huber2,3, Nicholas Z Rui4
1Institute for Astronomy, University of Hawaii, Honolulu, HI, USA. mtyhon@hawaii.edu.
Nature
|June 28, 2023
まとめ
太陽のような恒星を周回する惑星は 赤い巨人の段階を生き延びることができます ヘリウムを燃やす赤い巨星を 周回する巨大な惑星の発見は 恒星の進化の過程で 惑星の生存に関する以前の仮定に 挑戦しています
科学分野:
- 外惑星科学
- 星の進化について
- 天文学
背景:
- メインシーケンスの恒星は 赤い巨星へと膨張し 通常は近くにある惑星を 包み込みます
- 膨張後,コアでヘリウムを燃やす赤い巨星の周りに短期惑星が存在しないことは,惑星がこの段階に生き残れないことを示唆している.
- この欠落は,太陽のような恒星の周りの短期惑星の生存に対する証拠として解釈された.
研究 の 目的:
- ヘリウムで燃える赤い巨人の周りの 惑星の生存を調査する
- 恒星が膨張する時に 近くにある惑星が 破壊されるという説に 異議を唱えるためです
- 先進的な恒星進化の段階における 惑星の生存のための代替シナリオを探求する.
主な方法:
- 巨大惑星8 Ursae Minoris bの発見と特徴付け
- ホスト星の予想される赤巨人半径 (0.7 AU) に相対する惑星の軌道距離の分析.
- 惑星の生存を説明するために 軌道動力学と恒星の進化モデルを評価する
主要な成果:
- ヘリウムで燃える赤い巨星の周りを回っている 巨大な惑星の発見
- 惑星の近距離軌道 (0.5AU) は,赤い巨人期中に星に包まれていたことを示している.
- 惑星のほぼ円形の軌道は 遥かなる最初の軌道を 含む生存シナリオに挑戦します
結論:
- 核のヘリウムを燃やす赤い巨星は 近くにある惑星を宿すことができます
- 8 Ursae Minoris bの生存は,恒星の融合が起こり,恒星の進化が変化したり,第2世代の惑星ができたことを示唆している.
- このシステムは,外惑星系の長期的な生存に役割を果たす非正規の恒星進化の証拠を提供します.
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