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Extrasolar Planets. This exoplanet orbiting 51 pegasi is being vaporized by its’s parent star. A new Field to Study. Fundamental Astronomy questions Do other worlds exist? (last 15 years) Is there life on other worlds? (next 15 years). Extrasolar Planet. - PowerPoint PPT Presentation
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EXTRASOLAR PLANETS
This exoplanet orbiting 51 pegasi is being vaporized by its’s parent star
A NEW FIELD TO STUDY Fundamental Astronomy questions
Do other worlds exist? (last 15 years) Is there life on other worlds? (next 15 years)
EXTRASOLAR PLANET
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)
EXTRASOLAR SYSTEMS NUMBERS 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
PROPERTIES OF KNOWN EXTRASOLAR SYSTEMS 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
CHALLENGES FOR OBSERVING EXTRASOLAR 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)
DECTECTION METHODS Astronomic and Radial Velocity (235
systems) Transit Method (46 systems) Microlensing (6) Pulsar timeing (3)
ASTROMETRIC 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”
ASTROMETRIC DISPLACEMENT OF THE SUN DUE TO JUPITER
ASTROMETRIC METHOD
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
RADIAL VELOCITY 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 )
DOPPLER EFFECT Works for all kinds
of waves (including light)
Instead of pitch changing, color changes
Blue shift (object approaching)
Red Shift (object Receding)
http://www.youtube.com/watch?v=Man9ulEYSgk
http://www.youtube.com/watch?v=imoxDcn2Sgo
RADIAL VELOCITY METHOD 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
RVM
PROS CONS
Can be used for far away stars
Can only observe 1 star at a time
Difficult to detect terrestrial planets
SLOW