As a planet eclipses its parent star, a dark starspot may be occulted, causing a detectable variation in the light curve. This work describes how features on the surface of a solar-like star can be studied by using planetary transits. Recent transits observations for HD 209458 were used as tests to the model.Initially, images of the Sun were used in order to simulate such transits, with the planet being modeled as a dark disk at various positions along its orbit. However, this model was not the best fit to the high precision data of HD208459, which implied a different model for the limb darkening of the star. A model of the star with quadratic limb darkening was constructed and later used in the transits simulation.From these simulations it is possible to infer the physical properties of the spots, such as size, intensity, position, and temperature, not to mention properties of the stellar atmosphere.
Bulletin of the Astronomical Society of Brazil
- Pub Date:
- August 2003