Transcript What`s Out There?

WHAT’S OUT
THERE?
Detecting Extrasolar Planets
Rick Rutland
One way of detecting extrasolar planets
is called the transit method.
A transit is when the planet passes in
front of the star. How do you think
this might work? What would it look
like?
Draw a sketch of your prediction.
IS THIS WHAT YOU THOUGHT?
In reality, the stars are usually so
far away that scientists do not ever
see the actual star.
They use instruments to take
measurements of the star. Indirect
evidence is used to locate planets.
SCIENTISTS LOOK AT THE CHANGE IN
BRIGHTNESS OF THE STAR AS A PLANET PASSES
IN FRONT.
TWO FACTORS CAN GIVE US A GOOD
APPROXIMATION…
THE SCIENCE IS COMPLEX


The diameter of the planet compared to the diameter
of the star.
The orbital period of the planet (how long it takes to
orbit the star).
COMPARE THE DATA FOR THE TWO
PLANETS. WHAT MIGHT CAUSE THIS?
COMPARE THE DATA FOR THE TWO
PLANETS. WHAT MIGHT CAUSE THIS?
THIS STAR HAS TWO TRANSITING
EXTRASOLAR PLANETS.
Which choice fits
each planet?
SIZE OF THE PLANET CAN BE ESTIMATED
The first transiting extrasolar
planet was found orbiting a star
named HD 209458 in the
Pegasus constellation (150 light
years away). The data was
collected by the MOST space
telescope. HD 209458 is about
the same size as our sun, with a
diameter of 1,400,000 km.
SOURCES
http://blogs.ubc.ca/polarisdotca/astrolabs/extrasolar
-planets/
This presentation available at:
http://rickrutland.wikispaces.com
Vernier handouts available at:
http://www.vernier.com/experiments/