A Neptune-mass exoplanet in close orbit around a very low-mass star challenges formation models

• 成果类型: Article
• 署名作者: Stefansson, Gudmundur; Mahadevan, Suvrath; Miguel, Yamila; Robertson, Paul; Delamer, Megan; Kanodia, Shubham; Canas, Caleb I.; Winn, Joshua N.; Ninan, Joe P.; Terrien, Ryan C.; Holcomb, Rae; Ford, Eric B.; Zawadzki, Brianna; Bowler, Brendan P.; Bender, Chad F.; Cochran, William D.; Diddams, Scott; Endl, Michael; Fredrick, Connor; Halverson, Samuel; Hearty, Fred; Hill, Gary J.; Lin, Andrea S. J.; Metcalf, Andrew J.; Monson, Andrew; Ramsey, Lawrence; Roy, Arpita; Schwab, Christian; Wright, Jason T.; Zeimann, Gregory
• 署名单位: Princeton University; Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; Swiss Federal Institutes of Technology Domain; ETH Zurich; Leiden University; Leiden University - Excl LUMC; University of California System; University of California Irvine; Carnegie Institution for Science; National Aeronautics & Space Administration (NASA); NASA Goddard Space Flight Center; Tata Institute of Fundamental Research (TIFR); Carleton College; Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; University of Texas System; University of Texas Austin; University of Arizona; University of Texas System; University of Texas Austin; University of Texas System; University of Texas Austin; University of Colorado System; University of Colorado Boulder; National Institute of Standards & Technology (NIST) - USA; University of Colorado System; University of Colorado Boulder; National Aeronautics & Space Administration (NASA); NASA Jet Propulsion Laboratory (JPL); California Institute of Technology; United States Department of Defense; United States Air Force; US Air Force Research Laboratory; Space Telescope Science Institute; Johns Hopkins University; Macquarie University; Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; Pennsylvania State University - University Park; University of Texas System; University of Texas Austin
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-11248
• DOI: 10.1126/science.abo0233
• 发表日期: 2023-12-01
• 页码: 1031-1035
• 关键词: planet formation; m dwarfs; habitable-zone; gaia dr2; stellar; luminosity; constrain; dust

摘要

Theories of planet formation predict that low-mass stars should rarely host exoplanets with masses exceeding that of Neptune. We used radial velocity observations to detect a Neptune-mass exoplanet orbiting LHS 3154, a star that is nine times less massive than the Sun. The exoplanet's orbital period is 3.7 days, and its minimum mass is 13.2 Earth masses. We used simulations to show that the high planet-to-star mass ratio (>3.5 x 10(-3)) is not an expected outcome of either the core accretion or gravitational instability theories of planet formation. In the core-accretion simulations, we show that close-in Neptune-mass planets are only formed if the dust mass of the protoplanetary disk is an order of magnitude greater than typically observed around very low-mass stars.