exoplanets

Question 1

what is exoplanet

Answer 1

planet that orbits another star

Question 2

how many have we found

Answer 2

1000s

Question 3

how to find them

Answer 3

• direct: taking image of it
• indirect: infer presence with effects on the star

Question 4

direct

Answer 4

• stars = bright so hard to see planets close by (get blurred out)
• atmo blurring also makes it hard

Question 5

solution to blurring

Answer 5

adaptive optics

Question 6

solution to contrast

Answer 6

coronograph = blocks light of star to see planet

Question 7

what kind f planet will direct usually find

Answer 7

will find large planets far from star

Question 8

transits

Answer 8

• indirect
• planet passes in front of star
• orbits must be aligned edge on
• brightness changes porp to planet size
• 2nd dip is exlipse

Question 9

what is tranist good at finding

Answer 9

large planet close to star

Question 10

radial velocity method

Answer 10

• indirect
• mesure change of pos of star (wobble) due to planets using doppler shift

Question 11

what is radial good at fining

Answer 11

big close to sun

Question 12

grav lensing

Answer 12

uses relativity to look at background light of star

Question 13

what is grav lensing good at

Answer 13

far small

Question 14

most common size / dist of exos

Answer 14

close and big (hot jupiters)

because easier to detect with transit/doppler

Question 15

how to measure mass

Answer 15

measure amplitude of radial velocity

Question 16

how to measure distance

Answer 16

keplers 3rd law, dopper, transit

Question 17

how to measure size

Answer 17

transit

Question 18

how to measure density

Answer 18

transit + doppler

Question 19

percent of stars with a planet

Answer 19

70%

Question 20

how did jupiters get close to stars

Answer 20

they migrate from outer to inner