A MIRI Search for Planets and Dust around WD 2149+021

The launch of JWST has ushered in a new era of high precision infrared astronomy, permiting us to probe nearby white dwarfs for cold dust, exoplanets, and tidally heated exomoons. While previous searches for these exoplanets have successfully ruled out companions as small as 7-10 Jupiter masses, no instrument prior to JWST has been sensitive to the likely more common sub-Jovian mass planets around white dwarfs. In this paper, we present the first multi-band photometry (F560W, F770W, F1500W, F2100W) taken of \WD with the Mid-Infrared Instrument (MIRI) on JWST. After a careful examination for both resolved and unresolved planets, we do not identify any compelling candidates around \WD. Our analysis indicates that we should recover companions as small as $\sim$0.33 \Mjup\ beyond 0.654" ($\sim$14.7 au) with 5$\sigma$ confidence, placing significant constraints on any undetected companions around this white dwarf. The results of these observations emphasize the exciting future of sub-jovian planet detection limits.