This exoplanet orbiting 51 pegasi is being vaporized by its’s parent star

 Fundamental Astronomy questions  Do other worlds exist? (last 15 years)  Is there life on other worlds? (next 15 years)

 A Planet that orbits a star outside of our solar system  The picture is a drawing of Gliese 581 C (a star in a habitable zone)

 400 extrasolar systems  8 terrestial planets  182 gas giants  77 jupiters  2 neptunes  5 pulsar planets  3 kuiper belts  2 asteroid belts  14 forming solar systems with newly formed planets

 Why are most exoplanets gas giants that orbit close to the parent star?  Our current detection methods are biased towards finding gas giants close to a star  It is hard to find terrestrial planets

 Planets do not produce any light of their own  Planets are very far away  Glare from parent stars hide the planets  Closest planets to our solar system have never even been seen (we watch the star)

 Astronomic and Radial Velocity (235 systems)  Transit Method (46 systems)  Microlensing (6)  Pulsar timeing (3)

 Measures a stars position in the sky and observing how it changes over time  Gravitational pull of planet will cause the star to move in a tiny circle  Called “wobbling”

PROS CONS  1 telescope can search many stars at a time  Does not work for far away stars  Difficult to detect terrestrial planets which are smaller  SLOW

 Doppler effect  The change in frequency of a wave as perceived by a moving observer  Move towards (waves bunch up)  Move back (waves spread out )

 Works for all kinds of waves (including light)  Instead of pitch changing, color changes  Blue shift (object approaching)  Red Shift (object Receding)

 Sgk Sgk  2Sgo 2Sgo

 Measure the slight changes of a stars velocity as the star and planet move  When the star moves, the doppler shift of the starlight can be analyzed  Bigger the planet, bigger the doppler shift

PROSCONS  Can be used for far away stars  Can only observe 1 star at a time  Difficult to detect terrestrial planets  SLOW