JWST/MIRI imaging of white dwarfs: Searching for giant planets, brown dwarfs and debris disks

What is the fate of planetary systems after main-sequence stars have evolved through the red giant and asymptotic giant phases and become white dwarfs? While inner planets may be engulfed, others may survive to become post-common-envelope companions with ultra-short periods (1 to 10 hr). In principle, beyond 2-5 au, planets may survive and migrate to ~10 au or more after the star has lost a significant fraction of its mass. Surprisingly, only a handful of planets orbiting white dwarfs are currently known. Old planets orbiting white dwarfs are necessary cold (Teff < 300 K) and their peak emission found in the mid-infrared beyond 10 microns. We have embarked on the search for planets using JWST/MIRI imaging through different accepted programs since cycle 1 and present results here. Several red candidates have been identified within a few arc seconds around a set of white dwarfs and will be followed-up in cycle 5. Many white dwarfs show mid-IR excess consistent with debris disks or giant planets. At least one ultracool brown dwarf candidate was identified, MEAD 62B (Albert+2026). A cycle 1 deep imaging pilot survey of 4 white dwarfs identified 2 planet candidates. Although these were refuted with follow up observation as background galaxies, a more ambitious cycle 5 program will make a deep gaze of the 30 nearest white dwarfs and should be sensitive to planets with mass <1 Mjup.