Lecture 10

Question 1

Why is it so difficult to directly take a picture of an exoplanet?

Answer 1

over the vast interstellar distances the planet appears too close to a much brighter light source, the star

Question 2

Why is it usually very difficult (or even impossible) to directly image exoplanets around distant stars?

Answer 2

Because the faint image of the planet is overwhelmed by the super-bright image of the star

Question 3

Which planet is most likely to be detected by the radial velocity technique?

Answer 3

A massive planet orbiting close to its star

Question 4

Which planet is most likely to be detected by the transit technique?

Answer 4

A large planet orbiting close to its star

Question 5

Two planets were discovered using the radial velocity method and have nearly identical masses, but the Kepler mission found that planet 1 appears to be two times larger in diameter than planet 2. Which of the following is true?

Answer 5

The density of planet 2 must be greater than that of planet 1.

Question 6

What is the main reason why the Kepler telescope was launched into space?

Answer 6

because our atmosphere is too variable to find the small transit signals of Earth-size planets

Question 7

What are the major differences between the radial velocity (RV) and the transit (TR) technique for the indirect detection of extrasolar planets?

Answer 7

RV measures the mass, while TR measures the radius of the unseen planetary companion

Question 8

Why does the radial velocity method of detecting extrasolar planets only give us the minimum mass of a planet, i.e. a lower limit?

Answer 8

because we don’t know the angle the planet’s orbit makes with our line of sight

Question 9

Direct Detection

Answer 9

Attempt to discriminate light
originating from the planet (or reflected by it)
from direct radiation from the star.

Question 10

Indirect Detection

Answer 10

Detect effects of the
planetary system on the light from the star.