AHerschelresolved far-infrared dust ring around HD 207129

Abstract

Context. Dusty debris discs around main sequence stars are thought to be the result of continuous collisional grinding of planetesimals in the system. The majority of these systems are unresolved and analysis of the dust properties is limited by the lack of information regarding the dust location. Aims. The Herschel DUNES key program is observing 133 nearby, Sun-like stars (<20 pc, FGK spectral type) in a volume limited survey to constrain the absolute incidence of cold dust around these stars by detection of far infrared excess emission at flux levels comparable to the Edgeworth-Kuiper belt (EKB). Methods. We have observed the Sun-like star HD 207129 with Herschel PACS and SPIRE. In all three PACS bands we resolve a ringlike structure consistent with scattered light observations. Using α Boötis as a reference point spread function (PSF), we deconvolved the images, clearly resolving the inner gap in the disc at both 70 and 100 μm. Results. We have resolved the dust-producing planetesimal belt of a debris disc at 100 μm for the first time. We measure the radial profile and fractional luminosity of the disc, and compare the values to those of discs around stars of similar age and/or spectral type, placing this disc in context of other resolved discs observed by Herschel/DUNES.

Modelling the huge,Herschel-resolved debris ring around HD 207129

“…Our modelling is centred on the observational results presented in Marshall et al (2011). These data were obtained with Herschel/PACS and SPIRE in scan map and small map modes, respectively.…”

“…Following the strategy outlined in Müller et al (2010), we start from a first-guess setup based on the roughly known belt location (Krist et al 2010;Marshall et al 2011). After computation of the resulting SED and the radial profiles, we manually alter the most important (and least constrained) disk parameters and re-run the model until we reach a point from where no further significant improvements can be achieved that way.…”

“…(a) The given confidence intervals include calibration uncertainties. See Marshall et al (2011, their Spitzer/IRS spectrum then clearly samples the rise of the SED (see, e.g., Krist et al 2010). To homogenise the data for our modelling purposes, we extracted a single photometric point at 32 µm.…”

Scope for a small circumsolar annular gravitational contribution to the Pioneer anomaly without affecting planetary orbits

“…High values for mass in the Kuiper belt region of the present day, compared to the fractions of 0.1 M ⊕ found by studying precessional data for Mercury, Venus, Earth and Mars (Iorio 2007c), could only be gravitationally sustainable if the Kuiper belt formed a part of a greater annulus making near zero radial gravitation in the inner planetary region. But this is less of a constraint if the mass is located much further away in a belt extending to hundreds of AU, like the exo-Kuiper belts beginning to be observed around other Sun-like stars (Nilsson et al 2010;Marshall et al 2011;Donaldson et al 2012).…”

“…Quite separately, during the last decade, the evidence for the abundance of exoplanets and circumstellar disks containing gaps and rings gradually became very prominent, helping to place our Solar System into its evolutionary context (Meyer et al 2007;Moro-Martin et al 2008;Weinberger 2008;Moro-Martin 2013). Extensive exoKuiper belts around Sun-like stars are also being seen (Nilsson et al 2010;Marshall et al 2011;Donaldson et al 2012) and modeled in preparation for further observations (Ertel et al 2012). This perhaps suggests the importance today of looking more deeply into the physical possibilities lying beneath one particular stone, which we believe was first lifted in relation to the Pioneer anomaly, by de Diego et al (2006).…”