In this chapter we review the different methods for detection of extrasolar
planets. The main problem to find these objects comes form
• planets are smaller than stars,
• they only reflect light from a star,
• seen from a great distance they appear very close to their parent star,
• they mainly radiate in the IR.
The main detection methods are velocity measurements, astrometric measurements, direct
imaging, microlensing. Satellite missions such as KEPLER, COROT and GAIA are mentioned.
Today, it became even possible to detect exoplanetary atmospheres. Finally, the
different types of detected exoplanets are reviewed.
The main message of this chapter is that we are at the beginning to understand under which
conditions planets form around stars and how many of these planets could be Earthlike.
Keywords: Exoplanets; Detection of Exoplanets; radial velocity method; Doppler method;
microlensing; COROT; KEPLER, GAIA; Exoplanets: atmospheres; Exoplanets: types;
spectral lines
