The influence of stellar wind conditions on the detectability of planetary radio emissions

¹ Institut für Theoretische Physik, Technische Universität Braunschweig, Mendelssohnstraße 3, 38106 Braunschweig, Germany e-mail: j-m.griessmeier@tu-bs.de;u.motschmann@tu-bs.de
² Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany e-mail: gmann@aip.de
³ Institut für Weltraumforschung, Österreichische Akademie der Wissenschaften, Schmiedlstrasse 6, 8042 Graz, Austria e-mail: rucker@oeaw.ac.at

Received: 8 September 2004
Accepted: 21 February 2005

Abstract

Magnetized giant exoplanets in close orbits around their host star are expected to be strong nonthermal radio emitters. The anticipated radio flux is strong enough to allow its detection on Earth using the next generation of instruments. However, the measured quantity will not be the planetary radio flux but the sum of planetary and stellar emission. We compare the expected stellar and planetary radio signal for stellar systems of different ages. Solar-like stellar wind parameters as well as conditions corresponding to the young solar system (i.e. with increased stellar wind density and velocity) are considered. For young stellar systems, conditions appear to be more favorable than for older stellar systems. It is shown that configurations exist where the separation of the planetary signal from the stellar emission seems feasible.