「ヘアピンカーブ」に巻き込まれた太陽系外惑星が、質量の大きなガス惑星がどのように形成されるかを示唆(Exoplanet caught in ‘hairpin turn’ signals how high-mass gas giants form)

2024-07-17 ペンシルベニア州立大学(PennState)

＜関連情報＞

• https://www.psu.edu/news/research/story/exoplanet-caught-hairpin-turn-signals-how-high-mass-gas-giants-form/
• https://www.nature.com/articles/s41586-024-07688-3

超偏心逆行軌道にあるホットジュピター始祖惑星 A hot-Jupiter progenitor on a super-eccentric retrograde orbit

Arvind F. Gupta,Sarah C. Millholland,Haedam Im,Jiayin Dong,Jonathan M. Jackson,Ilaria Carleo,Jessica Libby-Roberts,Megan Delamer,Mark R. Giovinazzi,Andrea S. J. Lin,Shubham Kanodia,Xian-Yu Wang,Keivan Stassun,Thomas Masseron,Diana Dragomir,Suvrath Mahadevan,Jason Wright,Jaime A. Alvarado-Montes,Chad Bender,Cullen H. Blake,Douglas Caldwell,Caleb I. Cañas,William D. Cochran,Paul Dalba,… Carl Ziegler
Nature  Published:17 July 2024
DOI:https://doi.org/10.1038/s41586-024-07688-3

Abstract

Giant exoplanets orbiting close to their host stars are unlikely to have formed in their present configurations¹. These ‘hot Jupiter’ planets are instead thought to have migrated inward from beyond the ice line and several viable migration channels have been proposed, including eccentricity excitation through angular-momentum exchange with a third body followed by tidally driven orbital circularization^2,3. The discovery of the extremely eccentric (e = 0.93) giant exoplanet HD 80606 b (ref. ⁴) provided observational evidence that hot Jupiters may have formed through this high-eccentricity tidal-migration pathway⁵. However, no similar hot-Jupiter progenitors have been found and simulations predict that one factor affecting the efficacy of this mechanism is exoplanet mass, as low-mass planets are more likely to be tidally disrupted during periastron passage^6,7,8. Here we present spectroscopic and photometric observations of TIC 241249530 b, a high-mass, transiting warm Jupiter with an extreme orbital eccentricity of e = 0.94. The orbit of TIC 241249530 b is consistent with a history of eccentricity oscillations and a future tidal circularization trajectory. Our analysis of the mass and eccentricity distributions of the transiting-warm-Jupiter population further reveals a correlation between high mass and high eccentricity.