Magnetic coupling of planets and small bodies with a pulsar wind

¹ LUTH, Observatoire de Paris, CNRS, Unviersité Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France
e-mail: fabrice.mottez@obspm.fr
² Observatoire Astronomique, Université de Strasbourg, 11 rue de l’Université, 67000 Strasbourg, France
e-mail: jean.heyvaerts@astro.unistra.fr

Received: 17 January 2011
Accepted: 25 May 2011

Abstract

Aims. We investigate the electromagnetic interaction of a relativistic stellar wind with a planet or a smaller body in orbit around the star. This may be relevant to objects orbiting a pulsar that are expected to hold a planetary system, such as PSR B1257+12 and PSR B1620-26, or to pulsars with suspected asteroids or comets.

Methods. We extend the theory of Alfvén wings to relativistic winds.

Results. When the wind is relativistic but slower than the total Alfvén speed, a system of electric currents carried by a stationary Alfvénic structure is driven by the planet or by its surroundings.For an Earth-like planet around a “standard” second pulsar, the associated current can reach the same magnitude as the Goldreich-Julian current that powers the pulsar’s magnetosphere.