Proceedings of the International Astronomical Union

Direct Imaging of Exoplanets: Science & Techniques
Contributed Papers

Search and investigation of extra-solar planets with polarimetry

H. M. Schmid a1, J.-L. Beuzit a2, M. Feldt a3, D. Gisler a1, R. Gratton a4, Th. Henning a3, F. Joos a1, M. Kasper a5, R. Lenzen a3, D. Mouillet a6, C. Moutou a7, A. Quirrenbach a8, D. M. Stam a9, C. Thalmann a1, J. Tinbergen a10, C. Verinaud a5, R. Waters a9 and R. Wolstencroft a11
a1 Institute of Astronomy, ETH Zurich, Switzerland
a2 Laboratoire d'Astrophysique, Observatoire de Grenoble, France
a3 Max-Planck-Institut für Astronomie, Heidelberg, Germany
a4 INAF, Osservatorio Astronomico di Padova, Italy
a5 European Southern Observatory, Garching, Germany
a6 Laboratoire d'Astrophysique, Observatoire Midi-Pyrénées, Tarbes, France,
a7 Laboratoire d'Astrophysique de Marseille, France
a8 Sterrewacht, Leiden University, the Netherlands
a9 Astronomical Institute “Anton Pannekoek”, University of Amsterdam, the Netherlands
a10 ASTRON, Dwingeloo, the Netherlands
a11 Astronomy Technology Center, Royal Observatory Edinburgh, UK

Article author query
schmid hm   [Google Scholar] 
beuzit j   [Google Scholar] 
feldt m   [Google Scholar] 
gisler d   [Google Scholar] 
gratton r   [Google Scholar] 
henning t   [Google Scholar] 
joos f   [Google Scholar] 
kasper m   [Google Scholar] 
lenzen r   [Google Scholar] 
mouillet d   [Google Scholar] 
moutou c   [Google Scholar] 
quirrenbach a   [Google Scholar] 
stam dm   [Google Scholar] 
thalmann c   [Google Scholar] 
tinbergen j   [Google Scholar] 
verinaud c   [Google Scholar] 
waters r   [Google Scholar] 
wolstencroft r   [Google Scholar] 
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Light reflected from planets is polarized. This basic property of planets provides the possibility for detecting and characterizing extra-solar planets using polarimetry. The expected polarization properties of extra-solar planets are discussed that can be inferred from polarimetry of “our” solar system planets. They show a large variety of characteristics depending on the atmospheric and/or surface properties. Best candidates for a polarimetric detection are extra-solar planets with an optically thick Rayleigh scattering layer.

Even the detection of highly polarized extra-solar planets requires a very sophisticated instrument. We present the results from a phase A (feasibility) study for a polarimetric arm in the ESO VLT planet finder instrument. It is shown that giant planets around nearby stars can be searched and investigated with an imaging polarimeter, combined with a powerful AO system and a coronagraph at an 8 m class telescope.

A similar type of polarimeter is also considered for the direct detection of terrestrial planets using an AO system on one of the future Extremely Large Telescopes.

Key Words: exoplanets; scattering; polarization; instrumentation.