Chapter 13: Other Planetary Systems Flashcards
What are the three methods for detecting extra solar planets?
The astrometric, doppler, and transit method.
What is the astrometric method?
This method uses very precise measurments to detect motion in stars.
What is the doppler method?
This method looks for doppler shifts to detect steller movement.
What is the transit method?
This method searches for transits and eclipses by monitoring a stars brightness over a period of time.
Why can the transit method only detect a fraction of extrasolar planets?
The transit method requires the planet’s orbit to be lined up such that the planet passes between earth and its star.
What are the key advantages to the astrometric method?
Detects planets in all orbit orientations except edge-on.
What are the key advantages to the doppler method?
Possible from ground based telescopes
Detects planets in all orbit orientations except face on
What are the key advantages to the transit method?
Allows many stars to be oberved at once
Can detect very small planets
Feasible with small telescopes
Can probide some atmospheric data in cases of measurable eclipses
What are the major limitations with the astrometric method?
Generally possible only for relatively nearby stars
Biased towards finding massive planets that orbit far from their stars
May require years of obervation to detect these planets
What are the major limitations with the doppler method?
Biased toward finding massive planet with close in orbits
Underestimates star’s true motion exept when system viewed edge-on
Requires stellar spectra which means large telescopes and long observation times
What are the major limitations with the transit method?
Possible only for planets with edge-on orbits as viewed from earth
For small planets, requires sensitivity possible only from space observatory
What is a “hot jupiter”?
A extrasolar gas giant that orbits close to the sun.
What method(s) can be used to determine planetary distance? How are they used?
The astrometric, doppler, and transit method can all be used to determine the orbital distance of a planet. This is done using the orbital period and Newton’s version of Kepler’s third law.
What method(s) can be used to determine planetary eccentricity? How are they used?
The doppler and the astrometric method can be used. This is done by creating velocity curves and by using astrometric star positions.
What method(s) can be used to determine planetary inclination? How are they used?
The transit method and the astrometric method can be used. This is because astrometric methods measure any inclination angle, and transits can only be used on edge on orbits.
