Predicting low-frequency radio fluxes of known extrasolar planets

Abstract

Context. Close-in giant extrasolar planets ("Hot Jupiters") are believed to be strong emitters in the decametric radio range. Aims. We present the expected characteristics of the low-frequency magnetospheric radio emission of all currently known extrasolar planets, including the maximum emission frequency and the expected radio flux. We also discuss the escape of exoplanetary radio emission from the vicinity of its source, which imposes additional constraints on detectability. Methods. We compare the different predictions obtained with all four existing analytical models for all currently known exoplanets. We also take care to use realistic values for all input parameters. Results. The four different models for planetary radio emission lead to very different results. The largest fluxes are found for the magnetic energy model, followed by the CME model and the kinetic energy model (for which our results are found to be much less optimistic than those of previous studies). The unipolar interaction model does not predict any observable emission for the present exoplanet census. We also give estimates for the planetary magnetic dipole moment of all currently known extrasolar planets, which will be useful for other studies. Conclusions. Our results show that observations of exoplanetary radio emission are feasible, but that the number of promising targets is not very high. The catalog of targets will be particularly useful for current and future radio observation campaigns (e.g. with the VLA, GMRT, UTR-2 and with LOFAR).

On the Radio Detection of Multiple-Exomoon Systems Due to Plasma Torus Sharing

“…This value provides a maximum cut off frequency for all the moons in the system. If the radius of the exoplanet is not known when calculating f max , many authors (e.g., Grießmeier et al 2007, and references therein) choose to assume » R R P J . Studies on the radius-mass relationship of exoplanets show that = R R P J is a good approximation for Jovian exoplanets (Mordasini et al 2012, and references therein), and therefore we will use this approximation as well.…”

Time-scales of close-in exoplanet radio emission variability

“…Properties for these three systems are shown in Table 1 with details for the full sample available in Fares et al (2013). We choose these three systems for further discussion because they are often cited as promising targets for detectable exoplanetary radio emission (Lazio et al 2004;Grießmeier et al 2007b; and have been extensively studied in the literature. In addition, these stars allow a comparison of two critical factors that affect exoplanetary radio emission.…”

Magnetic energy fluxes in sub-Alfvénic planet star and moon planet interactions

“…In the case of Io, the existence of an atmosphere and ionosphere is sufficient to cause a strong interaction with the magnetospheric plasma of Jupiter and to generate powerful Alfvén wings. Grießmeier et al (2004Grießmeier et al ( , 2005Grießmeier et al ( , 2007 investigate SPI with particular emphasis on the radio emission from extrasolar planets and their detectability from Earth depending on various parameters such as stellar wind properties. Zarka et al (2001), Zarka (2006Zarka ( , 2007, and Hess & Zarka (2011) also investigate the plasma interaction of extrasolar planets with their parent star and their associated putative radio emission.…”