Planetary engulfment as a trigger for white dwarf pollution

Abstract

The presence of a planetary system can shield a planetesimal disk from the secular gravitational perturbations due to distant outer massive objects (planets or stellar companions). As the host star evolves off the main sequence to become a white dwarf, these planets can be engulfed, triggering secular instabilities and leading to the tidal disruptions of small rocky bodies. These disrupted bodies can feed the white dwarfs with rocky material and possibly explain the high-metallicity material in their atmospheres. We illustrate how this mechanism can operate when the gravitational perturbations are due to the Kozai-Lidov mechanism from a stellar binary companion. We show that this mechanism can explain the observed levels of accretion if: (1) the planetary engulfment happens fast compared to the secular timescale, which is generally the case for wide binaries ($>100$ AU) and planetary engulfment during the Asymptotic Giant Branch; (2) the planetesimal disk has a total mass of $\sim 10^{-4}-10^{-2}{M}_{\oplus }$. We show that this new mechanism can provide a steady supply of material throughout the entire life of the white dwarfs for all cooling ages and can account for a large fraction (up to nearly half) of the observed polluted WDs.

14 pages, 4 figures. Revised version after referee's comments. Major changes include a new Figure 1 and section 4.4

References in corpus (19)

• The frequency of planetary debris around young white dwarfs
• Transience of hot dust around sun-like stars
• The Chemical Composition of an Extrasolar Minor Planet
• Foretellings of Ragnarök: World-engulfing Asymptotic Giants and the Inheritance of White Dwarfs
• Hot Jupiters and Cool Stars
• Suppression of extreme orbital evolution in triple systems with short range forces
• Hot Jupiters from Coplanar High-eccentricity Migration
• Formation of planetary debris discs around white dwarfs I: Tidal disruption of an extremely eccentric asteroid
• Keplerian discs around post-AGB stars: a common phenomenon?
• Satellite dynamics on the Laplace surface
• Steady-state planet migration by the Kozai-Lidov mechanism in stellar binaries
• The primordial binary population II: Recovering the binary population for intermediate mass stars in Sco OB2
• Detectable close-in planets around white dwarfs through late unpacking
• Chaotic Disintegration of the Inner Solar System
• White dwarf pollution by planets in stellar binaries
• The Occurrence of Wide-Orbit Planets in Binary Star Systems
• Dynamical Stability of Imaged Planetary Systems in Formation: Application to HL Tau
• Dusty Disks Around Central Stars of Planetary Nebulae
• Witnessing the Emergence of a Carbon Star

Cited by in corpus (30)

• The unbiased frequency of planetary signatures around single and binary white dwarfs using $Spitzer$ and $Hubble$
• The Fate of Binaries in the Galactic Center: The Mundane and the Exotic
• Numerical Simulations of Collisional Cascades at the Roche Limits of White Dwarf Stars
• Explaining the variability of WD 1145+017 with simulations of asteroid tidal disruption
• Tidal disruption of planetary bodies by white dwarfs I: A hybrid SPH-analytical approach
• Tidal disruption of planetary bodies by white dwarfs II: Debris disc structure and ejected interstellar asteroids
• Multiple Stellar Evolution: a population synthesis algorithm to model the stellar, binary, and dynamical evolution of multiple-star systems
• Numerical Simulations of Gaseous Disks Generated from Collisional Cascades at the Roche Limits of White Dwarf Stars
• Alkali metals in white dwarf atmospheres as tracers of ancient planetary crusts
• Bayesian constraints on the origin and geology of exo-planetary material using a population of externally polluted white dwarfs
• Circularization of tidal debris around white dwarfs: implications for gas production and dust variability
• The fates of Solar system analogues with one additional distant planet
• Post-main-sequence debris from rotation-induced YORP break-up of small bodies II: multiple fissions, internal strengths and binary production
• The lifetimes of planetary debris discs around white dwarfs
• Binary star influence on post-main-sequence multi-planet stability
• Collisions in a gas-rich white dwarf planetary debris disc
• Orbital relaxation and excitation of planets tidally interacting with white dwarfs
• Accretion of tidally disrupted asteroids onto white dwarfs: direct accretion versus disk processing
• Properties of von Zeipel-Lidov-Kozai oscillations in triple systems at the quadrupole order: relaxing the test particle approximation
• Post main sequence evolution of icy minor planets II: water retention and white dwarf pollution around massive progenitor stars
• Circumbinary exoplanets and brown dwarfs with the Laser Interferometer Space Antenna
• Post-main-sequence evolution of icy minor planets. III. water retention in dwarf planets and exo-moons and implications for white dwarf pollution
• Survivability of radio-loud planetary cores orbiting white dwarfs
• The critical binary star separation for a planetary system origin of white dwarf pollution
• The entry geometry and velocity of planetary debris into the Roche sphere of a white dwarf
• The unstable fate of the planet orbiting the A-star in the HD 131399 triple stellar system
• Short-term stability of particles in the WD J0914+1914 white dwarf planetary system
• High-resolution resonant portraits of a single-planet white dwarf system
• Binary asteroid dissociation and accretion around white dwarfs
• PHL 5038AB: Is the brown dwarf causing pollution of its white dwarf host star?