Resolving the cold debris disc around a planet-hosting star: PACS photometric imaging observations of q^1 Eridani (HD 10647, HR 506)

Context. About two dozen exo-solar debris systems have been spatially resolved. These debris discs commonly display a variety of structural features such as clumps, rings, belts, excentric distributions and spiral patterns. In most cases, these features are believed to be formed, shaped and maintained by the dynamical influence of planets orbiting the host stars. In very few cases has the presence of the dynamically important planet(s) been inferred from direct observation. Aims. The solar-type star q 1 Eri is known to be surrounded by debris, extended on scales of 53 ◦ . The results of image de-convolution indicate that i likely is larger than 63 ◦ , where 90 ◦ corresponds to an edge-on disc. Conclusions. The observed emission is thermal and optically thin. The resolved data are consistent with debris at temperatures below 30 K at radii larger than 120 AU. From image de-convolution, we find that q 1 Eri is surrounded by an about 40 AU wide ring at the radial distance of ∼85 AU.