  This letter reports the first JWST spectroscopy of a white dwarf debris disk,
giving a preliminary assessment of the salient features, and recommendations
for future observations. The polluted and dusty star WD 0145+234 experienced a
major collisional event in its circumstellar disk in 2018, accompanied by an
infrared outburst, and subsequently a gradual decrease in thermal emission.
Time-series NIRSPEC observations demonstrate that the circumstellar disk is
returning to a quiescent state with a T~1000 K infrared excess similar to the
bulk of known dusty white dwarfs. MIRI spectroscopy reveals a 9-12 micron
solid-state emission feature consistent with silicate minerals as observed in
debris disks observed with Spitzer IRS. The strength and morphology of the
silicate feature appear unchanged relative to the continuum in spectra taken
over a year apart, consistent with steady-state collisional evolution of the
circumstellar debris. A tentative emission feature around 7 microns may be due
to carbonates, and if confirmed would indicate aqueous alteration in the parent
body.
