Collisional modelling of the debris disc around HIP 17439

Abstract

We present an analysis of the debris disc around the nearby K2 V star HIP 17439. In the context of the Herschel DUNES key programme the disc was observed and spatially resolved in the far-IR with the Herschel PACS and SPIRE instruments. In a first model, Ertel et al. (2014) assumed the size and radial distribution of the circumstellar dust to be independent power laws. There, by exploring a very broad range of possible model parameters several scenarios capable of explaining the observations were suggested. In this paper, we perform a follow-up in-depth collisional modelling of these scenarios trying to further distinguish between them. In our models we consider collisions, direct radiation pressure, and drag forces, i.e. the actual physical processes operating in debris discs. We find that all scenarios discussed in Ertel et al. are physically sensible and can reproduce the observed SED along with the PACS surface brightness profiles reasonably well. In one model, the dust is produced beyond 120au in a narrow planetesimal belt and is transported inwards by Poynting-Robertson and stellar wind drag. A good agreement with the observed radial profiles would require stellar winds by about an order of magnitude stronger than the solar value, which is not supported, although not ruled out, by observations. Another model consists of two spatially separated planetesimal belts, a warm inner and a cold outer one. This scenario would probably imply the presence of planets clearing the gap between the two components. Finally, we show qualitatively that the observations can be explained by assuming the dust is produced in a single, but broad planetesimal disc with a surface density of solids rising outwards, as expected for an extended disc that experiences a natural inside-out collisional depletion. Prospects of discriminating between the competing scenarios by future observations are discussed.

Astronomy and Astrophysics (accepted for publication). 11 pages, 8 figures

References in corpus (11)

• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Southern Sample
• Variations on Debris Disks: Icy Planet Formation at 30-150 AU for 1-3 Solar Mass Main Sequence Stars
• The Extrasolar Planet epsilon Eridani b - Orbit and Mass
• Long-Term Collisional Evolution of Debris Disks
• Steady-State Size Distributions for Collisional Populations: Analytical Solution with Size-Dependent Strength
• Collisional processes and size distribution in spatially extended debris discs
• Resolved Debris Discs Around A Stars in the Herschel DEBRIS Survey
• Outer edges of debris discs: how sharp is sharp?
• On the Relationship Between Debris Disks and Planets
• Correlations between the stellar, planetary and debris components of exoplanet systems observed by $\text{Herschel}$

Cited by in corpus (10)

• Solution to the debris disc mass problem: planetesimals are born small?
• Debris Disc Constraints on Planetesimal Formation
• Warm exo-Zodi from cool exo-Kuiper belts: the significance of P-R drag and the inference of intervening planets
• A $75\%$ Occurrence Rate of Debris Discs around F stars in the $\beta$ Pic Moving Group
• Does warm debris dust stem from asteroid belts?
• Dust Spreading in Debris Discs: Do Small Grains Cling on to Their Birth Environment?
• The influence of dust grain porosity on the analysis of debris disc observations
• A PR drag origin for the Fomalhaut disk's pervasive inner dust: constraints on collisional strengths, icy composition, and embedded planets
• Interferometric Detection and Orbit Modeling of the Subcomponent in the Hot-dust System $\kappa$ Tuc A: A Low-mass Star on an Eccentric Orbit in a Hierarchical-quintuple System
• A Catalogue of Interstellar Material Delivery From Nearby Debris Disks