Imaging extrasolar planets: GPI, GPI2, and miniature starshade

Apr 09, 2020 - 11:00 am to 12:00 pm
Bruce Macintosh (KIPAC) via zoom

Zoom Recording

In the landscape of exoplanet detection and characterization, direct imaging - spatially separating the planet from its parent star - remains the most challenging technique: all but the most massive and young planets are extremely faint, and the outer parts of planetary systems that imaging can access appear to be less populated than the inner reaches. Since the first set of discoveries in 2008, only a small number of planets have been imaged. Still, the spectral, orbital and statistical characterization of these systems has opened a window into a region inaccessible to other techniques. 

I will give an overview of the field and summarize the results of the  Gemini Planet Imager Exoplanet Survey (GPIES), the most comprehensive search for young wide-orbit giant planets to date. The extensive GPI survey helped us identify key factors for ground-based adaptive optics exoplanet imaging. Based on those, we are planning an upgrade: GPI 2.0. We will move the Gemini Planet Imager to the Gemini North telescope, upgrading the AO system and spectrograph to allow a new search for younger and lower-mass planets, precise characterization of target planets including atmospheric variability, and robust facilitiy operation for a range of non-exoplanet science applications.  

Moving beyond the young giant planets will require either Extremely Large Telescopes, space-based adaptive optics coronagraphs, or space telescope + free-flying starshade combinations. I will review possible pathways for such instruments, including the WFIRST coronagraph technology demonstration. Starshades - where a carefully-apodized opaque spacecraft blocks the light of the star for a formation-flying telescope - are a particularly promising but untested approach. We have developed a concept for mDOT, a small-satellite starshade mission to validate the technology while carrying out a science program. It combines a 3-m starshade with a cubesat telescope in a sun-synchronous low earth orbit, and would be capable of imaging low-density asteroidal or cometary debris disks around nearby stars.