HET Seminar

Like a Wrecking Ball: Understanding giant planets as the key to finding Earths

To find truly Earth-like planets, we must understand Jupiter-like planets. Cold giant planets appear to be correlated with small inner planets.

Nearly 200 cold giant planets are known from radial-velocity planet searches. But their true masses remain unknown due to the limitations of the technique. Gaia astrometry, paired with the radial velocities, permits measurements of 3-dimensional architecture for these systems. We show examples of Jupiter analogs for which this analysis has made surprising revelations. Understanding full system architectures is critical for modelling their dynamical histories.

The presence of giant planets can also disrupt the orbits of inner habitable worlds. Surprisingly, archival radial-velocity data remain unable to exclude giant planets near the habitable zone for many nearby stars to be targeted by future direct imaging surveys such as NASA's planned Habitable Worlds Observatory. Small, flexibly-scheduled telescopes can make significant contributions to our knowledge of these systems. I describe the Minerva-Australis telescope array: built as the only southern hemisphere observatory wholly dedicated to the detailed follow-up of planet candidates from NASA's Transiting Exoplanet Survey Satellite (TESS). We have contributed to the confirmation of 40 planets to date.  I give some results from our six years of operation, including preliminary results from our new multi-telescope photometric capability to validate small TESS planet candidates.