Resolving the cold debris disc around a planet-hosting star . PACS photometric imaging observations of q1 Eridani (HD 10647, HR 506)
René Liseau
(1)
,
Carlos Eiroa
(2)
,
D. Fedele
(2)
,
Jean-Charles Augereau
(3)
,
Goran Olofsson
(4)
,
B. González
(5)
,
Jesús Maldonado
(2)
,
B. Montesinos
(6)
,
A. Mora
(2)
,
Olivier Absil
(7)
,
David Ardila
(8)
,
David Barrado
(6)
,
Amelia Bayo
(6)
,
Charles A. Beichman
(9)
,
G. Bryden
(10)
,
William C. Danchi
(11)
,
Carlos del Burgo
(12)
,
Steve Ertel
(13)
,
Malcolm C. Fridlund
(14)
,
A. M. Heras
(14)
,
Alexander V. Krivov
(15)
,
Ralf Launhardt
(16)
,
J. Lebreton
(3)
,
T. Löhne
(15)
,
J. P. Marshall
(17)
,
Gwendolyn Meeus
(2)
,
S. Müller
(15)
,
G. L. Pilbratt
(14)
,
A. Roberge
(11)
,
J. Rodmann
(18)
,
E. Solano
(6)
,
Karl R. Stapelfeldt
(10)
,
Philippe Thébault
(19)
,
Glenn J. White
(17)
,
Sebastian Wolf
(13)
1
OSO -
Onsala Space Observatory, Chalmers University of Technology
2 Departamento de Física Teórica, Universidad Autónoma de Madrid
3 LAOG - Laboratoire d'Astrophysique de Grenoble
4 Stockholm Observatory, AlbaNova University Center
5 INSA at European Space Astronomy Centre (ESAC), European Space Agency, Apartado de Correos 78
6 Centro de Astrobiología LAEX (CSIC-INTA)
7 Institut d'Astrophysique, Géophysique et Océanographie, Université de Liège
8 SSC - Spitzer Science Center, California Institute of Technology
9 NASA Exoplanet Science Institute, California Institute of Technology, Pasadena
10 JPL - Jet Propulsion Laboratory
11 NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics, Code 667, Greenbelt
12 UNINOVA-CA3 - Computational Intelligence Research Group
13 Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel
14 ESA Astrophysics & Fundamental Physics Missions Division, ESTEC/SRE-SA
15 Astrophysikalisches Institut und Universitätssternwarte, Friedrich-Schiller-Universität Jena
16 MPIA - Max-Planck-Institut für Astronomie
17 Department of Physics and Astronomy, Open University, Walton Hall
18 ESA Space Environment and Effects Section, ESTEC
19 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
2 Departamento de Física Teórica, Universidad Autónoma de Madrid
3 LAOG - Laboratoire d'Astrophysique de Grenoble
4 Stockholm Observatory, AlbaNova University Center
5 INSA at European Space Astronomy Centre (ESAC), European Space Agency, Apartado de Correos 78
6 Centro de Astrobiología LAEX (CSIC-INTA)
7 Institut d'Astrophysique, Géophysique et Océanographie, Université de Liège
8 SSC - Spitzer Science Center, California Institute of Technology
9 NASA Exoplanet Science Institute, California Institute of Technology, Pasadena
10 JPL - Jet Propulsion Laboratory
11 NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics, Code 667, Greenbelt
12 UNINOVA-CA3 - Computational Intelligence Research Group
13 Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel
14 ESA Astrophysics & Fundamental Physics Missions Division, ESTEC/SRE-SA
15 Astrophysikalisches Institut und Universitätssternwarte, Friedrich-Schiller-Universität Jena
16 MPIA - Max-Planck-Institut für Astronomie
17 Department of Physics and Astronomy, Open University, Walton Hall
18 ESA Space Environment and Effects Section, ESTEC
19 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
Résumé
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 q1 Eri is known to be surrounded by debris, extended on scales of ⪅30''. The star is also known to host at least one planet, albeit on an orbit far too small to make it responsible for structures at distances of tens to hundreds of AU. The aim of the present investigation is twofold: to determine the optical and material properties of the debris and to infer the spatial distribution of the dust, which may hint at the presence of additional planets.
Methods: The Photodetector Array Camera and Spectrometer (PACS) aboard the Herschel Space Observatory allows imaging observations in the far infrared at unprecedented resolution, i.e. at better than 6'' to 12'' over the wavelength range of 60 mum to 210 mum. Together with the results from ground-based observations, these spatially resolved data can be modelled to determine the nature of the debris and its evolution more reliably than what would be possible from unresolved data alone.
Results: For the first time has the q1 Eri disc been resolved at far infrared wavelengths. The PACS observations at 70 mum, 100 mum and 160 mum reveal an oval image showing a disc-like structure in all bands, the size of which increases with wavelength. Assuming a circular shape yields the inclination of its equatorial plane with respect to that of the sky, i > 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 q1 Eri is surrounded by an about 40 AU wide ring at the radial distance of ~85 AU. This is the first real Edgeworth-Kuiper Belt analogue ever observed.
Aims: The solar-type star q1 Eri is known to be surrounded by debris, extended on scales of ⪅30''. The star is also known to host at least one planet, albeit on an orbit far too small to make it responsible for structures at distances of tens to hundreds of AU. The aim of the present investigation is twofold: to determine the optical and material properties of the debris and to infer the spatial distribution of the dust, which may hint at the presence of additional planets.
Methods: The Photodetector Array Camera and Spectrometer (PACS) aboard the Herschel Space Observatory allows imaging observations in the far infrared at unprecedented resolution, i.e. at better than 6'' to 12'' over the wavelength range of 60 mum to 210 mum. Together with the results from ground-based observations, these spatially resolved data can be modelled to determine the nature of the debris and its evolution more reliably than what would be possible from unresolved data alone.
Results: For the first time has the q1 Eri disc been resolved at far infrared wavelengths. The PACS observations at 70 mum, 100 mum and 160 mum reveal an oval image showing a disc-like structure in all bands, the size of which increases with wavelength. Assuming a circular shape yields the inclination of its equatorial plane with respect to that of the sky, i > 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 q1 Eri is surrounded by an about 40 AU wide ring at the radial distance of ~85 AU. This is the first real Edgeworth-Kuiper Belt analogue ever observed.