Final Spitzer IRAC Observations of the Rise and Fall of SN 1987A
  Spitzer's final Infrared Array Camera (IRAC) observations of SN 1987A show
the 3.6 and 4.5 $\mu$m emission from the equatorial ring (ER) continues a
period of steady decline. Deconvolution of the images reveals that the emission
is dominated by the ring, not the ejecta, and is brightest on the west side.
Decomposition of the marginally resolved emission also confirms this, and shows
that the west side of the ER has been brightening relative to the other
portions of the ER. The infrared (IR) morphological changes resemble those seen
in both the soft X-ray emission and the optical emission. The integrated ER
light curves at 3.6 and 4.5 $\mu$m are more similar to the optical light curves
than the soft X-ray light curve, though differences would be expected if dust
is responsible for this emission and its destruction is rapid. Future
observations with the James Webb Space Telescope will continue to monitor the
ER evolution, and will reveal the true spectrum and nature of the material
responsible for the broadband emission at 3.6 and 4.5 $\mu$m. The present
observations also serendipitously reveal a nearby variable source, subsequently
identified as a Be star, that has gone through a multi-year outburst during the
course of these observations.
