Incidence of debris discs around FGK stars in the solar neighbourhood^⋆

¹ Departmento de Astrofísica, Centro de Astrobiología (CAB, CSIC-INTA), ESAC Campus, Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
e-mail: benjamin.montesinos@cab.inta-csic.es
² Universidad Autónoma de Madrid, Dpto. Física Teórica, Módulo 15, Facultad de Ciencias, Campus de Cantoblanco, 28049 Madrid, Spain
³ Unidad Asociada CAB–UAM  
⁴ Astrophysikalisches Institut und Universitätssternwarte, Friedrich-Schiller-Universität, Schillergäßchen 2−3, 07745 Jena, Germany
⁵ School of Physics, UNSW Australia, NSW 2052 Sydney, Australia
⁶ Australian Centre for Astrobiology, UNSW Australia, NSW , 2052 Sydney, Australia
⁷ ESA, Directorate of Science, Scientific Support Office, European Space Research and Technology Centre (ESTEC/SCI-S), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
⁸ Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
⁹ ESA-ESAC Gaia SOC, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
¹⁰ INAF, Osservatorio Astronomico di Palermo, Piazza Parlamento 1, 90134 Palermo, Italy
¹¹ Institute of Theoretical Physics and Astrophysics, Christian-Albrechts University Kiel, Leibnizstr. 15, 24118 Kiel, Germany
¹² Steward Observatory, Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
¹³ Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Av. Gran Bretaña 1111, 5030 Casilla, Valparaíso, Chile
¹⁴ ICM Nucleus on Protoplanetary Disks, Universidad de Valparaíso, Av. Gran Bretaña 1111, 2360102 Valparaíso, Chile
¹⁵ Univ. Grenoble Alpes, IPAG, 38000 Grenoble, France
¹⁶ CNRS, IPAG, 38000 Grenoble, France
¹⁷ Leiden Observatory, University of Leiden, PO Box 9513, 2300 RA Leiden, The Netherlands
¹⁸ NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics, Code 667, Greenbelt, MD 20771, USA
¹⁹ Spanish Virtual Observatory, Centro de Astrobiología (CAB, CSIC-INTA), ESAC Campus, Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
²⁰ Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis Enrique Erro 1, Santa María de Tonantzintla, Puebla, México
²¹ Departamento de Astrofísica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid, Spain

Received: 17 February 2016
Accepted: 18 May 2016

Abstract

Context. Debris discs are a consequence of the planet formation process and constitute the fingerprints of planetesimal systems. Their counterparts in the solar system are the asteroid and Edgeworth-Kuiper belts.

Aims. The aim of this paper is to provide robust numbers for the incidence of debris discs around FGK stars in the solar neighbourhood.

Methods. The full sample of 177 FGK stars with d ≤ 20 pc proposed for the DUst around NEarby Stars (DUNES) survey is presented. Herschel/PACS observations at 100 and 160 μm were obtained, and were complemented in some cases with data at 70 μm and at 250, 350, and 500 μm SPIRE photometry. The 123 objects observed by the DUNES collaboration were presented in a previous paper. The remaining 54 stars, shared with the Disc Emission via a Bias-free Reconnaissance in IR and Sub-mm (DEBRIS) consortium and observed by them, and the combined full sample are studied in this paper. The incidence of debris discs per spectral type is analysed and put into context together with other parameters of the sample, like metallicity, rotation and activity, and age.

Results. The subsample of 105 stars with d ≤ 15 pc containing 23 F, 33 G, and 49 K stars is complete for F stars, almost complete for G stars, and contains a substantial number of K stars from which we draw solid conclusions on objects of this spectral type. The incidence rates of debris discs per spectral type are 0.26^+0.21_-0.14 (6 objects with excesses out of 23 F stars), 0.21^+0.17_-0.11 (7 out of 33 G stars), and 0.20^0.14_-0.09 (10 out of 49 K stars); the fraction for all three spectral types together is 0.22^+0.08_-0.07 (23 out of 105 stars). The uncertainties correspond to a 95% confidence level. The medians of the upper limits of L_dust/L_∗ for each spectral type are 7.8 × 10^-7 (F), 1.4 × 10^-6 (G), and 2.2 × 10^-6 (K); the lowest values are around 4.0 × 10^-7. The incidence of debris discs is similar for active (young) and inactive (old) stars. The fractional luminosity tends to drop with increasing age, as expected from collisional erosion of the debris belts.