A Giant Planet Candidate Orbiting a Young, Massive White Dwarf

From a sample of nearby, young, massive white dwarfs with archival Spitzer/IRAC photometry, we have identified one source with 4.5 micron flux excesses that are inconsistent with debris disks or background galaxy contamination. This source is best explained by a binary system unresolved in Spitzer's 2" PSF consisting of a white dwarf primary and a hot, young secondary with 5 Jupiter mass. If this planetary interpretation is correct, then we expect the white dwarf primary and planetary secondary in this system to have F444W ~ 18 and angular separation in excess of 0.2". The white dwarf primary would have had M_star ~ 8 M_Sun and been classified as B stars on the main sequence. Observing this or analogous systems from the ground with GPI 2.0 or SPHERE would require currently impossible-to-achieve H-band contrast ratios in excess of 10^10 at 0.2". We propose to spectrally and likely spatially resolve this system with JWST NIRSpec IFU to confirm or reject the planetary explanation for its photometry. If the proposed observation recover point sources with planet-like spectra, then it will be the first unambiguously planet-mass objects found orbiting objects that are or were main sequence B stars. The exquisite resolution and sensitivity of the JWST applied to this spatially and spectrally resolvable system will produce high signal-to-noise ratio near-infrared emission spectra of planet-mass objects with precise system age.