Seismology of Planets

Determining the internal structure of the Gas and Ice Giant Planets (i.e., Jupiter, Saturn, Uranus and Neptune) is key to understanding their formation and evolution, and in turn understanding the formation and evolution of the solar system. However, despite many years of study, the internal structure and dynamics of the Giant Planets remains obscure.  We are involved in several ground-based projects to validate the technique of Doppler seismology to probe the dynamics of the atmosphere, internal structure, and the coupling between the deep interior and atmosphere of both Jupiter and Saturn, both establishing the technique as a viable tool, and making the first measurements of the core mass and internal rotation profiles of these planets.

Panel A: An “MOF” image, where the absorption line can be seen on the left portion of the disk. Panel B: The simultaneous “continuum” image. Panel C: The Dopp- lergram produced by division of the MOF image by the corresponding continuum image. Within this Dopplergram, pixel intensity values correspond to Doppler velocities towards and away from the observer within the dark absorption band. These frames were collected on the night of 12 August 2020 from the AEOS 3.6m telescope; here, a 13.76 km s−1 relative velocity between observer and Jovian disk center is present, and roughly 200 pixels span the entirety of the disk

We are working with researchers at JPL and the US Air Force Research Laboratory on making proof-of-concept measurements for a dual-channel Doppler imager based on magneto-optical filters. This instrument was first validated using the 3.5 m AEOS telescope on Maui during the summer of 2020. We plan to deploy it with the LANDIT telescope for long-term observations of Jupiter and Saturn either from the geographic South Pole or the PEARL site on Ellesmere Island in Canada.

Left: The LANDIT 0.5m telescope. Middle: CAD drawing of the complete LANDIT focal plane instrument suite. The dual-channel Doppler imager is on the right, the broadband polarimeter is on the left. Right: The actual system as of July 2019. One channel is missing from the Doppler imager.