1. Exoplanets
Ioannis Paraskevas

2. Introduction planets outside the Solar System
First exoplanet announced in 1992
More than a thousand such planets have been discovered (1075)
 3,568 candidate planets
nearest known exoplanet, is Alpha Centauri Bb
 confirmed planets are gas giants

3. Problems with detection
Vast distances
Small
Dim

4. Methods of detection Radial velocity Transit method
Gravitational microlensing

5. Radial velocity method
by far the most productive method
star moves in its own small orbit around the system's center of mass
radial velocity can be detected from spectral lines
Extremely small radial-velocity variations, 1 m/s or even somewhat less

7. Transit method second most productive method
planet crosses in front of its parent star
observed brightness of the star drops by a small amount
reveals the radius of a planet

9. Gravitational microlensing
gravitational field of a star acts like a lens
magnifies the light of a distant background star
 most sensitive to detecting planets around
1–10 AU away from Sun-like stars

10. Ultimate goal Find : an Earth-like planet
Extraterrestrial civilizations

11. Thank you for listening
Any questions ?