01
Detection Methods
- Transit method detects periodic dimming when a planet crosses its star.
- Radial-velocity measurements detect stellar motion induced by an orbiting planet.
- Direct imaging attempts to separate planetary light from the much brighter host star.
- Microlensing detects temporary gravitational magnification caused by foreground planetary systems.
02
Atmospheric Characterization
Spectroscopy can reveal molecular absorption and emission features in planetary atmospheres under favorable observational conditions.
03
Habitability
Habitability is not equivalent to the presence of life. It concerns whether environmental conditions could permit life as understood by current science.
- Liquid-water stability is one important consideration.
- Atmospheric composition matters.
- Stellar radiation environment matters.
- Planetary mass and gravity influence atmospheric retention.
- Geological and chemical cycles can affect long-term conditions.