  We present new high-resolution mid-infrared imaging, high-resolution optical
spectroscopy, and Chandra grating X-ray spectroscopy of the weak-lined T Tauri
star DoAr 21. DoAr 21 (age < 10^6 yr and mass ~ 2.2 M_sun) is a strong X-ray
emitter, with conflicting evidence in the literature about its disk properties.
It shows weak but broad H-alpha emission; polarimetric variability; PAH and H2
emission; and a strong, spatially-resolved 24-micron excess in archival Spitzer
photometry. Gemini sub-arcsecond-resolution 9--18 micron images show that there
is little or no excess mid-infrared emission within 100 AU of the star; the
excess emission is extended over several arcseconds, is quite asymmetric, and
is bright in the UV-excited 11.3 micron PAH emission feature. A new
high-resolution X-ray grating spectrum from Chandra shows that the stellar
X-ray emission is very hard and dominated by continuum emission; it is well-fit
by a multi-temperature thermal model and shows no evidence of unusually high
densities. We argue that the far-ultraviolet emission from the star's
transition region is sufficient to excite the observed extended PAH and
continuum emission, and that the H2 emission may be similarly extended and
excited. This extended emission may be more akin to a small-scale
photodissociation region than a protoplanetary disk, highlighting both the very
young ages (< 10^6 yr) at which some stars are found without disks, and the
extreme radiation environment around even late-type pre--main-sequence stars.
