Volume 570, October 2014
|Number of page(s)||13|
|Section||Interstellar and circumstellar matter|
|Published online||31 October 2014|
Interpreting the extended emission around three nearby debris disc host stars
School of Physics, University of New South Wales, NSW,
2 Australian Centre for Astrobiology, University of New South Wales, NSW, 2052 Sydney, Australia
3 Departamento de Física Teórica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
4 Christian-Albrechts-Universität zu Kiel, Institut für Theoretische Physik und Astrophysik, Leibnizstr. 15, 24098 Kiel, Germany
5 European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001 Santiago, Chile
6 University Grenoble Alpes, IPAG, 38000 Grenoble, France
7 CNRS, IPAG, 38000 Grenoble, France
8 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK
9 Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, 7820436 Macul, Santiago, Chile
10 Department of Astrophysics, Centre for Astrobiology (CAB,CSIC-INTA), ESAC Campus, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
11 Herzberg Astronomy & Astrophysics, National Research Council of Canada, 5071 West Saanich Rd, Victoria, BC V9E 2E7, Canada
12 University of Victoria, Finnerty Road, Victoria, BC, V8W 3P6, Canada
Received: 2 July 2014
Accepted: 13 August 2014
Context. Cool debris discs are a relic of the planetesimal formation process around their host star, analogous to the solar system’s Edgeworth-Kuiper belt. As such, they can be used as a proxy to probe the origin and formation of planetary systems like our own.
Aims. The Herschel open time key programmes “DUst around NEarby Stars” (DUNES) and “Disc Emission via a Bias-free Reconnaissance in the Infrared/Submillimetre” (DEBRIS) observed many nearby, sun-like stars at far-infrared wavelengths seeking to detect and characterize the emission from their circumstellar dust. Excess emission attributable to the presence of dust was identified from around ~20% of stars. Herschel’s high angular resolution (~7′′ FWHM at 100 μm) provided the capacity for resolving debris belts around nearby stars with radial extents comparable to the solar system (50–100 au).
Methods. As part of the DUNES and DEBRIS surveys, we obtained observations of three debris disc stars, HIP 22263 (HD 30495), HIP 62207 (HD 110897), and HIP 72848 (HD 131511), at far-infrared wavelengths with the Herschel PACS instrument. Combining these new images and photometry with ancilliary data from the literature, we undertook simultaneous multi-wavelength modelling of the discs’ radial profiles and spectral energy distributions using three different methodologies: single annulus, modified black body, and a radiative transfer code.
Results. We present the first far-infrared spatially resolved images of these discs and new single-component debris disc models. We characterize the capacity of the models to reproduce the disc parameters based on marginally resolved emission through analysis of two sets of simulated systems (based on the HIP 22263 and HIP 62207 data) with the noise levels typical of the Herschel images. We find that the input parameter values are recovered well at noise levels attained in the observations presented here.
Key words: circumstellar matter / stars: individual: HIP 22263 / stars: individual: HIP 62207 / stars: individual: HIP 72848 / infrared: stars
© ESO, 2014
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