Figure 2: In this figure three different transits of an exoplanet in front of its host star and the resulting obliquity and RM curves are shown. Due to the star rotating on its rotation axis, it causes one hemisphere to be blueshifted, and the other redshifted as seen from an observer on Earth. The path of the exoplanet in front of the star is shown with the thick black arrows black. The dashed curves show the expected RV signal if the planet was not blocking any light while the solid line is the ‘RM curve’ showing the expected RV variations during the transit. The shape of the curve is highly dependent on the obliquity of the star. Figure credit: WASP-Planets.net