Formation of planetary debris discs around white dwarfs -II. Shrinking extremely eccentric collisionless rings

Dimitri Veras, Zoë M. Leinhardt, Siegfried Eggl, Boris T. Gänsicke

Research output: Contribution to journalArticlepeer-review


The formation channel of the tens of compact debris discs which orbit white dwarfs (WDs) at a distance of 1R remains unknown. Asteroids that survive the giant branch stellar phases beyond a few au are assumed to be dynamically thrust towards the WD and tidally disrupted within its Roche radius, generating extremely eccentric (e > 0.98) rings. Here, we establish that WD radiation compresses and circularizes the orbits of supermicron to cm-sized ring constituents to entirely within the WD's Roche radius. We derive a closed algebraic formula which well-approximates the shrinking time as a function of WD cooling age, the physical properties of the star and the physical and orbital properties of the ring particles. The shrinking time-scale increases with both particle size and cooling age, yielding age-dependent WD debris disc size distributions.

Original languageEnglish (US)
Pages (from-to)3453-3459
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Apr 24 2015
Externally publishedYes


  • Celestial mechanics
  • Methods: numerical
  • Minor planets, asteroids: general
  • Planets and satellites: dynamical evolution and stability
  • Protoplanetary discs
  • White dwarfs

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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