We present JWST images of the well-known planetary nebula NGC 6720 (the Ring
Nebula), covering wavelengths from 1.6μm to 25 μm. The bright shell is
strongly fragmented with some 20 000 dense globules, bright in H2, with a
characteristic diameter of 0.2 arcsec and density nH∼105-106
cm−3. The shell contains a thin ring of polycyclic aromatic hydrocarbon
(PAH) emission. H2 is found throughout the shell and in the halo. H2 in
the halo may be located on the swept-up walls of a biconal polar flow. The
central cavity is shown to be filled with high ionization gas and shows two
linear structures. The central star is located 2 arcsec from the emission
centroid of the cavity and shell. Linear features (`spikes') extend outward
from the ring, pointing away from the central star. Hydrodynamical simulations
are shown which reproduce the clumping and possibly the spikes. Around ten
low-contrast, regularly spaced concentric arc-like features are present; they
suggest orbital modulation by a low-mass companion with a period of about 280
yr. A previously known much wider companion is located at a projected
separation of about 15 000 au; we show that it is an M2-M4 dwarf. The system is
therefore a triple star. These features, including the multiplicity, are
similar to those seen in the Southern Ring Nebula (NGC 3132) and may be a
common aspect of such nebulae.Comment: 25 pages, 23 figures. Submitted to Monthly Notices of the Royal
Astronomical Society. Corrected typos in metadat