Cold dust around nearby stars (DUNES). First results: A resolved exo-Kuiper belt around the solar-like star zeta^2 Ret

TL;DR

This paper reports the first far-infrared observations of nearby solar-type stars, revealing a resolved exo-Kuiper belt around zeta^2 Ret and setting limits on debris disks around other stars.

Contribution

First far-IR imaging of nearby solar-type stars with detection of an exo-Kuiper belt around zeta^2 Ret using Herschel PACS.

Findings

Resolved eccentric dust ring around zeta^2 Ret

No significant debris disks detected around delta Pav, HR 8501, 51 Peg

Exo-Kuiper belt around zeta^2 Ret has Ldust/Lstar ~ 10^-5

Abstract

We present the first far-IR observations of the solar-type stars delta Pav, HR 8501, 51 Peg and zeta^2 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 um fluxes from delta Pav, HR 8501, and 51 Peg agree with the predicted photospheric fluxes, excluding debris disks brighter than Ldust/Lstar ~ 5 x 10^-7 (1 sigma level) around those stars. A flattened, disk-like structure with a semi-major axis of ~ 100 AU in size is detected around zeta^2 Ret. The resolved structure suggests the presence of an eccentric dust ring, which we interpret as an exo-Kuiper belt with Ldust/Lstar ~ 10^-5.