Draft version January 19, 2015 Preprint typeset using LATEX style emulateapj v. 05/12/14 DOES THE PRESENCE OF PLANETS AFFECT THE FREQUENCY AND PROPERTIES OF EXTRASOLAR KUIPER BELTS? RESULTS FROM THE HERSCHEL DEBRIS AND DUNES SURVEYS A. Moro-Mart´ın1,2, J. P. Marshall3,4,5, G. Kennedy6, B. Sibthorpe7, B.C. Matthews8,9, C. Eiroa5, M.C. Wyatt6, J.-F. Lestrade10, J. Maldonado11, D. Rodriguez12, J.S. Greaves13, B. Montesinos14, A. Mora15, M. Booth16, G. Duchene^ 17,18,19, D. Wilner20, J. Horner21,4, Draft version January 19, 2015 ABSTRACT The study of the planet-debris disk connection can shed light on the formation and evolution of planetary systems, and may help \predict" the presence of planets around stars with certain disk characteristics. In preliminary analyses of subsamples of the Herschel DEBRIS and DUNES surveys, Wyatt et al. (2012) and Marshall et al. (2014) identified a tentative correlation between debris and the presence of low-mass planets. Here we use the cleanest possible sample out these Herschel surveys to assess the presence of such a correlation, discarding stars without known ages, with ages < 1 Gyr and with binary companions <100 AU, to rule out possible correlations due to effects other than planet presence. In our resulting subsample of 204 FGK stars, we do not find evidence that debris disks are more common or more dusty around stars harboring high-mass or low-mass planets compared to a control sample without identified planets. There is no evidence either that the characteristic dust temperature of the debris disks around planet-bearing stars is any different from that in debris disks without identified planets, nor that debris disks are more or less common (or more or less dusty) around stars harboring multiple planets compared to single-planet systems. Diverse dynamical histories may account for the lack of correlations. The data show a correlation between the presence of high-mass planets and stellar metallicity, but no correlation between the presence of low-mass planets or debris and stellar metallicity. Comparing the observed cumulative distribution of fractional luminosity to those expected from a Gaussian distribution in logarithmic scale, we find that a distribution centered on the Solar system's value fits well the data, while one centered at 10 times this value can be rejected. This is of interest in the context of future terrestrial planet detection and characterization because it indicates that there are good prospects for finding a large number of debris disk systems (i.e. with evidence of harboring planetesimals, the building blocks of planets) with exozodiacal emission low enough to be appropriate targets for an ATLAST-type mission to search for biosignatures. Keywords: infrared: stars | solar system: interplanetary medium, Kuiper belt | stars: circumstellar matter, planetary systems, planet-disc interactions. 1. INTRODUCTION 1 Space Telescope Science Institute, 3700 San Martin Dr., Bal- timore, MD 21218, USA. email: [email protected] Planetesimals are the building blocks of planets and 2 Center for Astrophysical Sciences, Johns Hopkins University, mid- and far-infrared observations with Spitzer and Her- Baltimore MD 21218, USA. schel indicate that at least 10{25% of mature stars (ages 3 School of Physics, University of New South Wales, Sydney, of 10 Myr{10 Gyr) with a wide range of masses (cor- NSW 2052, Australia. 4 Australian Centre for Astrobiology, University of New South responding to spectral types A{M) harbor planetesimal Wales, Sydney, NSW 2052, Australia disks with disk sizes of 10s{100s AU. This frequency is a 5 Depto. F´ısicaTe´orica,Universidad Aut´onomade Madrid, Can- lower limit because the surveys are limited by sensitivity. toblanco, 28049, Madrid, Spain. 6 Institute of Astronomy (IoA), University of Cambridge, Mad- The evidence for planetesimals comes from the presence ingley Rd., Cambridge, CB3 0HA, UK. of infrared emission in excess of that expected from the 7 SRON Netherlands Institute for Space Research, NL-9747 AD, stellar photosphere, thought to arise from a circumstel- arXiv:1501.03813v1 [astro-ph.EP] 15 Jan 2015 Groningen, The Netherlands. lar dust disk; because the lifetime of the dust grains (<1 8 Herzberg Astronomy & Astrophysics, National Research Coun- cil of Canada, 5071 West Saanich Rd, Victoria, BC V9E 2E7, Myr) is much shorter than the age of the star (>10 Myr), Canada. it is inferred that the dust cannot be primordial but must 9 University of Victoria, Finnerty Road, Victoria, BC, V8W 3P6, be the result of steady or stochastic dust production gen- Canada. 10 Observatoire de Paris, CNRS, 61 Av. de lObservatoire, F- 75014, Paris, France. 16 Instituto de Astrof´ısica, Pont´ıficia Universidad Cat´olicade 11 INAF - Osservatorio Astronomico di Palermo, Piazza Parla- Chile, Vicu~naMackenna 4860, 7820436 Macul, Santiago, Chile. mento 1, 90134 Palermo, Italy. 17 Astronomy Department, University of California, Berkeley, 12 Universidad de Chile, Camino el Observatorio 1515, Las Con- CA 94720, USA. des, Santiago, Chile. 18 Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France. 13 SUPA, School of Physics and Astronomy, University of St. 19 CNRS, IPAG, F-38000 Grenoble, France. Andrews, North Haugh, St. Andrews KY16 9SS, UK. 20 Harvard-Smithsonian Center for Astrophysics, 60 Garden 14 Centro de Astrobiolog´ıa(CAB, CSIC-INTA), ESAC Campus, Street, Cambridge, MA 02138, USA. P.O. Box 78, 28691 Villanueva de la Ca~nada,Madrid, Spain. 21 Computational Engineering and Science Research Centre, 15 ESA-ESAC Gaia SOC. P.O. Box 78 E-28691 Villanueva de la University of Southern Queensland, West Street, Toowoomba Qld Ca~nada,Madrid, Spain. 4350, Australia. 2 erated by the collision, disruption and/or sublimation of Herschel observations have opened a new parameter planetesimals (for reviews, see Wyatt 2008, Krivov 2010 space that allows us to explore fainter and colder debris and Moro-Mart´ın2013, Matthews et al. 2014). disks, improving our knowledge of debris disk frequency, The Sun harbors such a debris disk produced by the in particular around later type stars. In addition, since asteroids, comets and Kuiper Belt objects (KBOs; Je- the Spitzer planet-debris disk correlation studies were witt et al. 2009), with a dust production rate that has carried out, a large number of low-mass planets have changed significantly with time, being higher in the past been detected, the frequency of which can now be char- when the asteroid and Kuiper belts were more densely acterized. Tentative detection of a correlation between populated (Booth et al. 2009). Today, the Solar sys- low-mass planets and debris disks was presented in Wy- tem's debris disk is fainter than the faintest extrasolar att et al. (2012), from a preliminary study based on a debris disks we can observe with Herschel (Moro-Mart´ın Herschel-DEBRIS subsample of the nearest 60 G-type 2003, Vitense et al. 2012), with a 3-σ detection limit at stars, which was also seen in the volume limited sample 10{20 times the level of dust in the current Kuiper Belt of radial velocity planet host stars examined by Mar- (KB; Eiroa et al. 2013, Matthews et al. in preparation). shall et al. (2014). In this paper, we revisit the planet- There is evidence of planetesimals around A- to M-type debris disk correlation (or lack thereof) in the Herschel stars in both, single- and multiple-star systems. These DEBRIS and DUNES surveys (Matthews et al. 2010; stars span several orders of magnitude difference in stel- Eiroa et al. (2010), 2013; Matthews et al. in prepara- lar luminosities, implying that planetesimal formation, a tion) to assess whether the frequency and properties of critical step in planet formation, is a robust process that debris disks around a control sample of stars are statis- can take place under a wide range of conditions. tically different from those around stars with high-mass It is therefore not surprising that planets and debris or low-mass planets. In a companion paper (Marshall disks co-exist (Beichman et al. 2005; Moro-Mart´ınet al. et al. 2014), we describe the individual exoplanet host 2007b, 2010; Maldonado et al. 2012; Wyatt et al. 2012, systems, their debris disks and the disk dependencies on Marshall et al. 2014). However, based on Spitzer debris planetary system properties such as planet semi-major disk surveys, no statistical correlation has been found, to axis and eccentricity. date, between the presence of known high-mass planets The selection criteria of the different samples used in and debris disks (Moro-Mart´ınet al. 2007a; Bryden et this study are presented in Section 2 (with a discussion of al. 2009; K´osp´alet al. 2009). These studies were fo- biases in Section 5). A detailed discussion of the statis- cused on high-mass planets (>30 M⊕) because, at the tical analysis using Kolmogorov-Smirnov (K-S), Fisher's time, the population of low-mass planets was unknown. exact and survival analysis tests can be found in Section Overall, the lack of correlation was understood within 3 (regarding the frequency and properties of debris disks the context that the conditions to form debris disks are and their dependence on the presence of high-mass and more easily met than the conditions to form high-mass low-mass planets), Section 4 (regarding the correlation planets, in which case one would not expect a correla- with stellar metallicity) and Section 6 (regarding the dis- tion based on formation conditions arguments; this was tribution of the debris disk fractional luminosities). For also consistent with the studies that showed that there a summary and discussion of our results the reader is is a correlation between stellar metallicity and the pres- directed to Section 7. ence of massive planets (Santos et al. 2004; Fisher & Valenti 2005; Maldonado et al.