2006ApJ...646.1038B

With the MIPS camera on Spitzer, we have searched for far-infrared emission from dust in the planetary system orbiting pulsar PSR B1257+12. With accuracies of 0.05 mJy at 24 µm and 1.5 mJy at 70 µm, photometric measurements find no evidence for emission at these wavelengths. These observations place new upper limits on the luminosity of dust with temperatures between 20 and 1000 K. They are particularly sensitive to dust temperatures of 100-200 K, for which they limit the dust luminosity to below 3x10^–5 of the pulsar's spin-down luminosity, 3 orders of magnitude better than previous limits. Despite these improved constraints on dust emission, an asteroid belt similar to the solar system's cannot be ruled out.