Project C
Aligned, askew, or wildly tilted? Measuring an exoplanet’s orbit
Bibiana Prinoth (ESO), Jens Kammerer (ESO), Sydney Vach (ESO), Juliana Ehrhardt (ESO, MPE)
When a planet passes in front of its star, it consecutively covers different parts of the stellar surface. Because stars rotate, each portion of the stellar disc has a slightly different velocity. This creates a temporary distortion in the star’s spectrum during transit – known as the Rossiter–McLaughlin effect – and acts as a powerful tracer of how a planet’s orbit is oriented relative to the star’s spin, offering key insights into how planetary systems form and how their orbits evolve over time.
This project will use high-resolution spectroscopic observations to detect and model the Rossiter–McLaughlin effect for a transiting exoplanet. The analysis involves converting time-series spectra into radial-velocity measurements, identifying the characteristic anomaly during transit, and fitting physical models that describe the star’s rotation and the planet’s path across the stellar disc. By comparing results across different wavelength regimes, the project will explore how observational setup influences the precision of spin-orbit measurements and may help guide future observing strategies.
