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arXiv 1702.07075astro-ph.EP
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作为行星环境探测器的天体物理射电源的掩星:木星的个例研究和对系外行星的可能应用

Occultations of astrophysical radio sources as probes of planetary environments: A case study of Jupiter and possible applications to exoplanets

Paul Withers, Marissa F. Vogt

摘要:

从地球上很难测量行星大气、电离层和磁层的性质。无线电掩星是测量这些特性的常用方法,但它们传统上依赖于行星附近航天器的无线电传输。在这里,我们探讨是否可以用来测量行星周围的磁场强度,等离子体密度和中性密度从遥远的天体物理射电源的无线电发射掩星。在木星的理论案例研究中,我们发现,由于法拉第旋转的偏振角发生显着变化的无线电信号,通过10个木星半径的行星和频率和功率发生显着变化的无线电信号,通过中性大气。有足够的候选射电源,如恒星、活动星系核和脉泽,掩星可能每年至少发生一次。对于等离子体,它们发射的脉冲到达的时间延迟可以用来测量等离子体密度。系外行星的物理性质非常难以观测,也可能隐藏着遥远的天体物理射电源,例如它们的母恒星。

英文摘要:

Properties of planetary atmospheres, ionospheres, and magnetospheres are difficult to measure from Earth. Radio occultations are a common method for measuring these properties, but they traditionally rely on radio transmissions from a spacecraft near the planet. Here we explore whether occultations of radio emissions from a distant astrophysical radio source can be used to measure magnetic field strength, plasma density, and neutral density around planets. In a theoretical case study of Jupiter, we find that significant changes in polarization angle due to Faraday rotation occur for radio signals that pass within 10 Jupiter radii of the planet and that significant changes in frequency and power occur from radio signals that pass through the neutral atmosphere. There are sufficient candidate radio sources, such as pulsars, active galactic nuclei, and masers, that occultations are likely to occur at least once per year. For pulsars, time delays in the arrival of their emitted pulses can be used to measure plasma density. Exoplanets, whose physical properties are very challenging to observe, may also occult distant astrophysical radio sources, such as their parent stars.

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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