The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here:

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Anders Johansen. Profile picture.

Anders Johansen


Anders Johansen. Profile picture.

The role of pebble fragmentation in planetesimal formation I. Experimental study


  • Mohtashim Bukhari Syed
  • Jürgen Blum
  • K. Wahlberg Jansson
  • A. Johansen

Summary, in English

Previous work on protoplanetary dust growth shows a halt at centimeter sizes owing to the occurrence of bouncing at velocities of 0.1 m s-1 and fragmentation at velocities ≳;1 m s-1. To overcome these barriers, spatial concentration of centimeter-sized dust pebbles and subsequent gravitational collapse have been proposed. However, numerical investigations have shown that dust aggregates may undergo fragmentation during the gravitational collapse phase. This fragmentation in turn changes the size distribution of the solids and thus must be taken into account in order to understand the properties of the planetesimals that form. To explore the fate of dust pebbles undergoing fragmenting collisions, we conducted laboratory experiments on dust-aggregate collisions with a focus on establishing a collision model for this stage of planetesimal formation. In our experiments, we analyzed collisions of dust aggregates with masses between 0.7 and 91 g mass ratios between target and projectile from 1 to 126 at a fixed porosity of 65%, within the velocity range of 1.5-8.7 m s-1, at low atmospheric pressure of ∼10-3 mbar, and in free-fall conditions. We derived the mass of the largest fragment, the fragment size/mass distribution, and the efficiency of mass transfer as a function of collision velocity and projectile/target aggregate size. Moreover, we give recipes for an easy-to-use fragmentation and mass-transfer model for further use in modeling work. In a companion paper, we use the experimental findings and the derived dust-aggregate collision model to investigate the fate of dust pebbles during gravitational collapse.


  • Lund Observatory - Has been reorganised

Publishing year





Astrophysical Journal





Document type

Journal article


American Astronomical Society


  • Astronomy, Astrophysics and Cosmology


  • comets: general
  • methods: laboratory
  • planets and satellites: formation
  • protoplanetary disks
  • techniques: image processing




  • ISSN: 0004-637X