High-Resolution Mid-infrared Imaging of SN 1987A

Using the Thermal Region Camera and Spectrograph (T-ReCS) attached to the Gemini South 8 m telescope, we have detected and resolved 10 μm emission at the position of the inner equatorial ring (ER) of supernova SN 1987A at day 6067. "Hot spots" similar to those found in the optical and near-IR are clearly present. The morphology of the 10 μm emission is globally similar to the morphology at other wavelengths from X-rays to radio. The observed mid-IR flux in the region of SN 1987A is probably dominated by emission from dust in the ER. We have also detected the ER at 20 μm at a 4 σ level. Assuming that thermal dust radiation is the origin of the mid-IR emission, we derive a dust temperature of 180 K and a dust mass of × 10-5 M☉ for the ER. Our observations also show a weak detection of the central ejecta at 10 μm. We show that previous bolometric flux estimates (through day 2100) were not significantly contaminated by this newly discovered emission from the ER. If we assume that the energy input comes from radioactive decays only, our measurements, together with the current theoretical models, set a temperature of 90 K ≤ T ≤ 100 K and a mass range of 10-4 to 2 × 10-3 M☉ for the dust in the ejecta. With such dust temperatures the estimated thermal emission is × 1035 ergs s-1 from the inner ring and × 1036 ergs s-1 from the ejecta. Finally, using SN 1987A as a template, we discuss the possible role of supernovae as major sources of dust in the universe.