Event

The Doppler technique is a key tool for discovering and characterizing planets orbiting other stars. By measuring periodic shifts in stellar spectral lines as a star and its planets orbit around the system center of mass, “exoplanets” can be discovered. In some cases, the masses of these planets can even be directly measured. These measurements allow us to probe the internal compositions of these newly discovered worlds, constrain models of planet formation, and put future direct measurements of planets’ atmospheric properties into context.  Over the past three decades, advances in technology have made it possible to achieve 1 m/s velocity precision in the measurements of Sun-like stars. However, if we hope to detect analogs of terrestrial planets like those in our solar system orbiting Sun-like stars, velocity precision will need to improve substantially. Earth induces just a 10 cm/s wobble in the Sun. Understanding a host of astrophysical and instrumental noise sources becomes important for measuring stellar velocities with a precision below 1 m/s. I will describe NEID and MINERVA-Red, two new instruments that my team here at Penn helped build, which are designed to push the limits of ground-based Doppler measurement precision and open up new scientific opportunities in exoplanet detection and characterization.