Magnetic environment of extrasolar moons revealed

Two researchers have tried shedding light on the magnetic environment of extrasolar moons.

Washington: Two researchers have tried shedding light on the magnetic environment of extrasolar moons.

Rene Heller of the Department of Physics and Astronomy at McMaster University (Canada) and Jorge I. Zuluaga of the FACom group in the Institute of Physics of the University of Antioquia (Colombia) explored the complex magnetic environment of exomoons and its impact on the habitability of these peculiar bodies. Regrettably the results are not completely encouraging.

Heller and Zuluaga studied moons having a mass and size similar to that of Mars orbiting planets with masses and compositions ranging from that of Neptune to Jupiter. Larger moons, with masses similar to that of Earth, are unlikely to have formed even around the largest planets, while moons lighter than Mars will not be easily detected in the near future.

The core of this new work is in the calculation of the size of the magnetospheres of giant planets that are located in the habitable zones of their host stars.

Planetary magnetospheres are `bubbles` made of fields and plasma created by the shock between the stellar wind and the intrinsic magnetic field of the planet.

These bubbles separate the immediate magnetic environment of the planet from the very different environment of the interplanetary space. Magnetospheres could be really huge.

Zuluaga and his team at the University of Antioquia have gathered knowledge about the generation and maintenance of magnetic fields in terrestrial and giant planets and use it to predict the intensities of those magnetic fields.

Heller and Zuluaga dug in to the well known models by Jonathan Fortney and collaborators at the University of California and used the properties of planets with different sizes and compositions to estimate their magnetic properties.

Applied to the already known solar system bodies, the methods developed by Zuluaga and his team are able to predict the so-called magnetic dipole moment of bodies ranging from Ganymede to Jupiter to the right order of magnitude. This is sufficient to predict magnetospheric sizes within a factor of 2.

The findings have been published in the Astrophysical Journal Letters.