Potential multi-component structure of the debris disk around HIP 17439 revealed by Herschel/DUNES^⋆

¹ UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, 38041 Grenoble, France
e-mail: steve.ertel@obs.ujf-grenoble.fr
² Dpt. de Física Teórica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
³ Astrophysikalisches Institut und Universitätssternwarte, Friedrich-Schiller-Universität, Schillergäßchen 2-3, 07745 Jena, Germany
⁴ ESA-ESAC Gaia SOC., PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
⁵ Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis Enrique Erro 1, Sta. Ma. Tonantzintla, Puebla, Mexico
⁶ European Space Observatory, Alonso de Cordova 3107, Vitacura Casilla 19001, Santiago 19, Chile
⁷ Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
⁸ NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics, Code 667, Greenbelt, MD 20771, USA
⁹ Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, Leibnizstraße 15, 24098 Kiel, Germany
¹⁰ Onsala Space Observatory, Chalmers University of Technology, 439 92 Onsala, Sweden
¹¹ ESA Astrophysics & Fundamental Physics Missions Division, ESTEC/SRE-SA, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
¹² Observatoire de Paris, Section de Meudon, Laboratoire d’études spatiales et d’instrumentation en astrophysique, 5 place Jules Janssen, 92195 Meudon Cedex, France
¹³ Department of Physics and Astrophysics, Open University, Walton Hall, Milton Keynes MK7 6AA, UK
¹⁴ Rutherford Appleton Laboratory, Chilton OX11 0QX, UK

Received: 3 July 2012
Accepted: 18 November 2013

Abstract

Context. The dust observed in debris disks is produced through collisions of larger bodies left over from the planet/planetesimal formation process. Spatially resolving these disks permits to constrain their architecture and thus that of the underlying planetary/planetesimal system.

Aims. Our Herschel open time key program DUNES aims at detecting and characterizing debris disks around nearby, sun-like stars. In addition to the statistical analysis of the data, the detailed study of single objects through spatially resolving the disk and detailed modeling of the data is a main goal of the project.

Methods. We obtained the first observations spatially resolving the debris disk around the sun-like star HIP 17439 (HD 23484) using the instruments PACS and SPIRE on board the Herschel Space Observatory. Simultaneous multi-wavelength modeling of these data together with ancillary data from the literature is presented.

Results. A standard single component disk model fails to reproduce the major axis radial profiles at 70  μm, 100  μm, and 160  μm simultaneously. Moreover, the best-fit parameters derived from such a model suggest a very broad disk extending from few au up to few hundreds of au from the star with a nearly constant surface density which seems physically unlikely. However, the constraints from both the data and our limited theoretical investigation are not strong enough to completely rule out this model. An alternative, more plausible, and better fitting model of the system consists of two rings of dust at approx. 30 au and 90 au, respectively, while the constraints on the parameters of this model are weak due to its complexity and intrinsic degeneracies.

Conclusions. The disk is probably composed of at least two components with different spatial locations (but not necessarily detached), while a single, broad disk is possible, but less likely. The two spatially well-separated rings of dust in our best-fit model suggest the presence of at least one high mass planet or several low-mass planets clearing the region between the two rings from planetesimals and dust.