文章基本信息

标题：Exoplanet Modulation of Stellar Coronal Radio Emission
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作者：Ofer Cohen ; Sofia-Paraskevi Moschou ; Alex Glocer 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2018
卷号：156
期号：5
页码：1-10
DOI：10.3847/1538-3881/aae1f2
语种：English
出版社：American Institute of Physics
摘要：The search for exoplanets in the radio bands has been focused on detecting radio emissions produced by the interaction between magnetized planets and the stellar wind (auroral emission). Here we introduce a new tool, which is part of our MHD stellar corona model, to predict the ambient coronal radio emission and its modulations induced by a close planet. For simplicity, the present work assumes that the exoplanet is stationary in the frame rotating with the stellar rotation. We explore the radio flux modulations using a limited parameter space of idealized cases by changing the magnitude of the planetary field, its polarity, the planetary orbital separation, and the strength of the stellar field. We find that the modulations induced by the planet could be significant and observable in the case of hot Jupiter planets— above 100% modulation with respect to the ambient flux in the 10–100MHz range in some cases, and 2%–10% in the frequency bands above 250MHz for some cases. Thus, our work indicates that radio signature of exoplanets might not be limited to low-frequency radio range. We find that the intensity modulations are sensitive to the planetary magnetic field polarity for short-orbit planets, and to the stellar magnetic field strength for all cases. The new radio tool, when applied to real systems, could provide predictions for the frequency range at which the modulations can be observed by current facilities.
关键词：planet–star interactions;planets and satellites: magnetic fields;plasmas;radio continuum: planetary systems;stars: magnetic field