Exoplanents: Are We Alone?

Question 1

The Drake Equation

Answer 1

Not useful at all to make actual guesses

But it points us to the questions we should be asking

Question 2

Detection methods: indirect

Answer 2

Measure wobble of parent star
Astrometric (GAIA, 2013+)
Periodic Doppler shift of light from star
Transit method

Question 3

What can we determine from Doppler shift method?

Answer 3

Orbital eccentricity and period
Orbital radius
Minimum mass (min bc planet may not be head on, could be tilted)

Question 4

What can we determine from transit method?

Answer 4

Orbital period and radius
Orbital inclination (has to be edge on)
Size (and atmosphere, temperature)

Question 5

Kepler mission

Answer 5

145000 main sequence stars
Images every 30 mins to detect brightness changes
Found >5000 candidate planets
Confirmed >2500

Question 6

Combining Doppler and transit data, what can you find?

Answer 6

Edge on:
Exact mass from Doppler
Size from transit
Average density (Rocky, gaseous, other?)

Question 7

Direct detection of exoplanets

Answer 7

Super hard
Angular differential imaging (ADI): find pixel-wise median of many rotated images, subtract from original images, de rotate and median average, etc…
Works best for young planets that are far from star

Question 8

What can you find from direct detection?

Answer 8

Atmosphere: spectra and images
Temperature, composition/chemistry
Weather

Question 9

The Thirty Meter Telescope

Answer 9

9x size of Keck

• dark matter and energy, tests Standard Model of Particle Physics
• characterization of first stars and galaxies in universe
• characterization of epoch of reionization
• galaxy assembly and evolution over 13 billion years
• star by star dissection of galaxies out to 10 Mparsecs
• physics of planet and star formation
• exoplanet discovery and characterization
• Kuiper belt object surface chem
• solar system planetary atmosphere chem and meteorology