Cold DUst around NEarby Stars (DUNES). First results : a resolved exo-Kuiper belt around the solar-like star ζ2 Ret

摘要

We present the first far-IR observations of the solar-type stars δ Pav, HR 8501, 51 Peg and ζ Ret, taken within the context of the DUNES Herschel open time key programme (OTKP). This project uses the PACS and SPIRE instruments with the objective of studying infrared excesses due to exo-Kuiper belts around nearby solar-type stars. The observed 100°μm fluxes from δ Pav, HR°8501, and 51°Peg agree with the predicted photospheric fluxes, excluding debris disks brighter than L/L ~ 5 × 10 (1σ level) around those stars. A flattened, disk-like structure with a semi-major axis of ~100°AU in size is detected around ζ Ret. The resolved structure suggests the presence of an eccentric dust ring, which we interpret as an exo-Kuiper belt with L/L ≈ 10-5.