The Search for Exoplanetary Radio Emissions (invited)

Abstract

A chronological review of this relatively recent subject is presented, from the discovery of the first exoplanet-orbiting a pulsar-to theoretical predictions and ongoing searches conducted with most large low-frequency radiotelescopes. The specific interest of radio observations is emphasized. 1 Historical Landmarks "Pre"-history of the field started with Yantis et al. [1977], Winglee et al. [1986], Lecacheux [1991], and Burke [1992], all making an analogy between Jupiter and putative exoplanets and suggesting to look for radio emissions of the latter. Most of them noticed that the high intensity of the galactic background is a serious drawback to the detectability of such emissions (see below). Winglee et al. [1986] conducted in addition a first search using the VLA at 330 MHz and 1.4 GHz, with negative results. The first exoplanet was discovered around the pulsar PSR1257+12, by pulse arrival timing, using the Arecibo radiotelescope at 430 MHz [Wolszczan and Frail, 1992]. In the same year, a Nançay-Meudon/Graz/Kharkov collaboration started around the use of the UTR-2 radiotelescope [Braude et al., 1978] together with modern Nançay receivers. The first tentative exoplanet search at UTR-2 started in 1995, in parallel with Jupiter studies, using an Acousto-Optical Spectrograph (AOS-[Raterron, 1985]) in the band 18-28 MHz. Its principles and method were presented at the first French workshop on exoplanet search, held at the Observatoire de Haute-Provence [Zarka, 1995]. In october 1995, the discovery of 51 Peg B around a solar type star [Mayor and Queloz, 1995] marked the true birth of a new field, which counts today >500 known exoplanets (see exoplanet.eu).

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