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arXiv 0906.2783astro-ph.EP
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在244和614兆赫上对凌日系外行星HD189733b的GMRT射电观测

GMRT radio observations of the transiting extrasolar planet HD189733b at 244 and 614 MHz

A. Lecavelier des Etangs, S. K. Sirothia, Gopal-Krishna, P. Zarka

摘要:

我们报告了一个敏感的搜索米波长的发射在244和614 MHz的HD 189733 b,最近的已知太阳系外凌行星的“热木星”型。为了区分任何行星发射可能的恒星或背景贡献,我们观察了7.7小时的系统,包括行星在主星后面的日食。这些GMRT观测提供了非常低的(3 sigma)上限,244 MHz时为2 mJy,614 MHz时为160 micro-Jy。这些极限分别比最近在340 MHz附近频率下报告的极限深约40倍和500倍。我们没有探测到的可能解释包括:(1)地球位于行星的发射光束之外;(2)它的发射变化很大,比我们观测到的时间采样更快;(3)行星的发射本质上太弱;或者更可能的是,(4)由于行星的磁场很弱,发射主要是在较低的频率。我们简要地讨论这些可能性和限制这个外行星系环境。

英文摘要:

We report a sensitive search for meter-wavelength emission at 244 and 614 MHz from HD189733b, the nearest known extrasolar transiting planet of `hot-Jupiter' type. To discriminate any planetary emission from possible stellar or background contributions, we observed the system for 7.7 hours encompassing the planet's eclipse behind the host star. These GMRT observations provide very low (3 sigma) upper limits of 2 mJy at 244 MHz and 160 micro-Jy at 614 MHz. These limits are, respectively, about 40 and 500 times deeper than those reported recently at a nearby frequency of 340 MHz. Possible explanations of our non-detection include: (1) the Earth being outside the planet's emission beam; (2) its highly variable emission with more rapid flaring than the temporal sampling in our observations; (3) the planetary emission being intrinsically too weak; or more likely, (4) the emission being predominantly at lower frequencies because of a weak planetary magnetic field. We briefly discuss these possibilities and the constraints on this exo-planetary system environment.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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