Identification of ultracool (<300 K) companion candidates around white dwarfs with JWST/MIRI direct imaging.

Loïc Albert ( Université de Montréal )

White dwarfs are the end product of almost all stars. What happens to planets after their parent star leaves the main sequence? Only a handful of planets have been found orbiting white dwarfs even though their survival is likely, especially at separations of 5 au or more. Sensitivity to the mid infrared where emissivity of these old, ultracool objects peaks was a limitation. MIRI onboard the Webb telescope opens a new era and several surveys of white dwarfs are ongoing to identify gas giants either resolved with direct imaging or unresolved through their infrared flux excess. On the basis of 2 JWST programs, we have identified a few candidate companions that we will present here.