Dynamical effects of stellar mass-loss on a Kuiper-like belt

By Amy Bonsor, A. Mustill, M. C. Wyatt. 2011

156 citations recorded by the source corpus.

A quarter of DA white dwarfs are metal polluted, yet elements heavier than helium sink down through the stellar atmosphere on time-scales of days. Hence, these white dwarfs must be the currently accreting material containing heavy elements. Here we consider whether the scattering of comets or asteroids from an outer planetary system, following stellar mass-loss on the asymptotic giant branch, can reproduce these observations. We use N-body simulations to investigate the effects of stellar mass-loss on a simple system consisting of a planetesimal belt whose inner edge is truncated by a planet. Our simulations find that, starting with a planetesimal belt population fitted to the observed main-sequence evolution, sufficient mass is scattered into the inner planetary system to explain the inferred heavy element accretion rates. This assumes that a fraction of the mass scattered into the inner planetary system ends up on star-grazing orbits, is tidally disrupted and is accreted on to the white dwarf. The simulations also reproduce the observed decrease in accretion rate with cooling age and predict accretion rates in old (>1 Gyr) white dwarfs, in line with observations. The efficiency we assumed for material scattered into the inner planetary system to end up on star-grazing orbits is based on a solar-like planetary system, since the simulations show that a single planet is not sufficient. Although the correct level of accretion is reproduced, the simulations predict a higher fraction of accreting white dwarfs than observed. This could indicate that the evolved planetary systems are less efficient in scattering bodies on to star-grazing orbits or that dynamical instabilities post-stellar mass-loss cause rapid planetesimal belt depletion for a significant fraction of systems.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/3388994b8207c4fc09163f5616d8a666e12e6136

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In Astronomy and Astrophysics

1. J. Farihi
2. Amy Bonsor
3. A. Mustill
4. D. Veras
5. B. Gänsicke
6. D. Koester
7. M. C. Wyatt
8. Z. Leinhardt

Citations in the corpus

• The frequency of planetary debris around young white dwarfs (2014, background): “Smaller bodies are likely to be scattered, from locations comparable to the solar system’s main asteroid belt or Kuiper belt (Bonsor et al. 2011; Debes et al. 2012), which will lead to their tidal disruption if their trajectory takes them within the Roche radius of the white dwarf,≈1 R⊙, (Davidsson…”
• Circumstellar Debris and Pollution at White Dwarf Stars (2016, methodology): “The principle of widening orbital resonances or chaotic zones was first applied to a NeptuneKuiper belt analog carried into the post-main sequence (Bonsor et al., 2011).”
• THE LINK BETWEEN PLANETARY SYSTEMS, DUSTY WHITE DWARFS, AND METAL-POLLUTED WHITE DWARFS (2012, methodology): “As noted previously in Bonsor et al. (2011), one can determine an accretion rate Ṁ onto WDs based on the fraction of asteroidal belt mass scattered (fSI), disrupted (fTD), and eventually accreted (facc), as well as the mean time of disruption < tTD >: Ṁmetal = faccfTDfSIMbelt < tTD > .”
• Formation of planetary debris discs around white dwarfs – I. Tidal disruption of an extremely eccentric asteroid (2014, background): “Here, we are unconcerned with the dynamical architectures that would be necessary to propel the asteroid to the WD in this manner (see Bonsor et al. 2011; Debes et al. 2012a; Frewen & Hansen 2014) but rather focus entirely on the disruption process.”
• Simulations of two-planet systems through all phases of stellar evolution: implications for the instability boundary and white dwarf pollution (2013, background): “Nevertheless, Bonsor et al. (2011) found that asteroidal accretion on to WDs from particles scattered due to the overlap of mean-motion resonance exterior to the planet follows a similar trend of being present beyond a few tens of Myr after postMS evolution before eventually tailing off after a few…”
• FORETELLINGS OF RAGNARÖK: WORLD-ENGULFING ASYMPTOTIC GIANTS AND THE INHERITANCE OF WHITE DWARFS (2012, background): “Such delivery mechanisms require dynamical instability, whether local instability of the metalliferous planetesimals (Bonsor et al. 2011; Bonsor & Wyatt 2012; Debes et al. 2012) or wholesale global instability (Debes & Sigurdsson 2002, D. Veras et al., MN- RAS, submitted).”
• The chemical diversity of exo-terrestrial planetary debris around white dwarfs (2012, background): “…that debris from the tidal disruption of main-belt analogue asteroids or minor planets (Graham et al. 1990; Jura 2003), or Kuiper-belt like objects (Bonsor et al. 2011), likely perturbed by unseen planets (Debes & Sigurdsson 2002; Debes et al. 2012), is the most likely origin of photospheric…”