1. Polarized Light from Exoplanets: The Key to Clouds and Hazes?
Pushkar Kopparla
Vijay Natraj
Yuk Yung
Matthew Wilcoxson

2. Polarization and Exoplanets
UNPOLARIZED
POLARIZED
UNPOLARIZED
Stam et al (2004)

3. Model Setup From Star To Earth
1. Create a model atmosphere and perform radiative transfer (with VLIDORT*)
2. Rotate polarization vectors into equatorial plane and sum over illuminated disc
*Spurr et al (2013)

4. Model Setup
3. Repeat at various phases and rotate into Earth’s sky plane
4. Compare with observations!
Berdyugina et al (2011)

5. Polarimetric Observations of HD 189733b
-π π
Observations at 0.36 and 0.44 micron
wavelength
-π π
Berdyugina et al (2011)

6. Model Output: Maximum Polarization
Rayleigh atmosphere
Geometric albedo 0.5
Model
Observations
Berdyugina et al (2011)

7. Conclusions
Polarized light from exoplanets contains information about atmospheric structure and orbital orientation.
We show that simple Rayleigh scattering comes close to but cannot fully account for the observed polarization of HD b.

8. End
Longitude of Ascending Node (omega)
planet Ω
star
To observer