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火星サイズの系外惑星ケプラー-138bの質量は,通過時刻から得られた
Daniel Jontof-Hutter1, Jason F Rowe2, Jack J Lissauer3
11] Department of Astronomy, Pennsylvania State University, Davey Laboratory, University Park, Pennsylvania 16802, USA [2] NASA Ames Research Center, Moffett Field, California 94035, USA.
Nature
|June 19, 2015
まとめ
研究者らは,ケプラー-138を周回する3つの惑星の大きさと質量を測定した. この研究は,火星サイズの惑星を含む小さな系外惑星の密度に関する重要なデータを提供します.
科学分野:
- エクソプラネット科学 エクソプラネット科学
- 星の天体物理学 星の天体物理学
- 惑星のダイナミクス
背景:
- トランジットの系外惑星は,サイズと軌道周期の直接測定を可能にします.
- 惑星間の重力相互作用は,通過時刻に影響を与え,質量の決定を可能にします.
- 岩石系系外惑星の特徴は,小さいサイズと質量のために困難です.
研究 の 目的:
- 恒星ケプラー-138の周りを回っている3つの惑星の大きさと質量を決定する.
- これらの系外惑星の質量密度を計算するために.
- 火星サイズの系外惑星を含む,潜在的な岩石惑星を特徴付ける.
主な方法:
- トランジット光度計は,系外惑星の大きさや軌道周期を測定する.
- 惑星の質量を推論するために,通過時間変動 (TTVs) の分析.
- 決定された質量とサイズを使用して散発密度の計算.
主要な成果:
- 内側の惑星,ケプラー-138bは火星の大きさで,質量は0.066地球の質量で,密度は2.6g/cm3.
- 中央と外側の惑星は地球の大きさで,密度はそれぞれ6.2g/cm3と2.1g/cm3です.
- 外側の惑星の低密度は,水または水素の重要な組成を示唆しています.
結論:
- この研究では,Kepler-138の3つの惑星の質量と密度を成功裏に特徴付けました.
- この発見は,小型系外惑星の質量を測定するTTVの能力を示している.
- ケプラー138系は,潜在的に水豊富な世界を含む惑星の組成の多様性についての洞察を提供します.
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