EXOPLANETS Flashcards
1
Q
HOW MANY
A
- more than 5000
2
Q
how can exoplanets be detected
A
- difficult to directly detect because the glare of the hoest star (earth would be 10^9 fainter than the sun from out of the solar system)
in 2004 first images were seen of planets directly
3
Q
methods of finding an exoplanet
A
- radial velocity
- transit
- microlensing
- astrometry
4
Q
how can radial velocity be used to detect exoplanets
A
- wavelength compression and stretching
- doppler wobbler effect
- can main sequence stars
however
only calculate min planet mass for orbits smaller than habitable zone
-
5
Q
how does the transit technique work
A
- measures planet radii and orbital distance
- Kepler (nasa) used the transit method to confirm 2,700 expolanets
6
Q
pros/cons of the transit technique
A
- can scan for changes in stellar brightness
-HOWEVER need to be along line-of sight (only 10 percent can be detected) and problem of false positives - the atmosphere can be detected-and atmospheric compositions, aswell as if the planet looks bigger at different wavelengths
7
Q
how is planet mass and orbital period related on hot jupiters
A
- hot jupiters orbit their host star in less than 100 days
- easier to detect, tidally locked, low densities
8
Q
how is mass and orbital period related on super earths
A
- masses larger than earth, smaller than neptune
- rocky, water?
9
Q
what system can be compared to the solar system
A
- the trappist-1 system (41 light years away)
- EXTREME QUICK ORBITS
- tidal locking
10
Q
name two exoplanet missions
A
- TESS
- CHEOPS
11
Q
what system was discovered by CHEOPS
A
TOI-178
planetary system with 5/6 exoplanets in orbital resonance
weird density discovered by CHEOPS
