Bending Of Light In Exoplanet Atmospheres

Hot Jupiters are large, gas giant planets orbiting other stars outside of our solar system (exoplanets). Most of the exoplanets that have been found are orbiting close to their stars, and so the starlight they receive heats them up to high temperatures. When the exoplanet's orbit is aligned with respect to Earth, we see it pass in front of the star. This phenomenon is called transit. During transit, part of the star's light passes through this exoplanet's atmosphere, and by measuring the changes in this light, we can get information about this distant planet's atmosphere. Certain types of light, for instance the "Sodium D line" interact much more strongly with the gas than generic white light. The goal of this project is to perform a theoretical calculation of the bending of light as it travels through these exoplanets' atmospheres, a phenomenon called refraction. Because light's trajectory is not straight, a telescope on Earth would detect light earlier (or later) during transit than one would expect from a straight line trajectory. The trajectory of the light through the exoplanet's atmosphere was computed through a numerical integration. New to this study is the inclusion of the strong dependence on wavelength for light near the Sodium D line. Different wavelengths of light can have different bending angles, unlike previous studies for white light. This poster will present examples of photon trajectories for different wavelengths of light, showing how they will be received, either earlier or later than expected for a straight line trajectory.