A. A. Vidotto, J. Llama, M. Jardine, Ch. Helling, K. Wood
Bow shocks can be formed around planets due to their interaction with the
coronal medium of the host stars. The net velocity of the particles impacting
on the planet determines the orientation of the shock. At the Earth's orbit,
the (mainly radial) solar wind is primarily responsible for the formation of a
shock facing towards the Sun. However, for close-in planets that possess high
Keplerian velocities and are frequently located at regions where the host
star's wind is still accelerating, a shock may develop ahead of the planet. If
the compressed material is able to absorb stellar radiation, then the signature
of bow shocks may be observed during transits. Bow-shock models have been
investigated in a series of papers (Vidotto et al. 2010, 2011,a,b; Llama et al.
2011) for known transiting systems. Once the signature of a bow-shock is
observed, one can infer the magnetic field intensity of the transiting planet.
Here, we investigate the potential to use this model to detect magnetic fields
of (hypothetical) planets orbiting inside the habitable zone of M-dwarf stars.
For these cases, we show, by means of radiative transfer simulations, that the
detection of bow-shocks of planets surrounding M-dwarf stars may be more
difficult than for the case of close-in giant planets orbiting solar-type
stars.
View original:
http://arxiv.org/abs/1112.1512
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