A Smoking Gun for Planetesimal Formation: Charge Driven Growth into a New Size Range

Abstract

Collisions electrically charge grains which promotes growth by coagulation. We present aggregation experiments with three large ensembles of basalt beads ($150\mu \mathrm{m}-180\mu \mathrm{m})$, two of which are charged, while one remains almost neutral as control system. In microgravity experiments, free collisions within these samples are induced with moderate collision velocities ($0-0.2{\mathrm{m}\mathrm{s}}^{-1}$). In the control system, coagulation stops at (sub-)mm size while the charged grains continue to grow. A maximum agglomerate size of 5\,cm is reached, limited only by bead depletion in the free volume. For the first time, charge-driven growth well into the centimeter range is directly proven by experiments. In protoplanetary disks, this agglomerate size is well beyond the critical size needed for hydrodynamic particle concentration as, e.g., by the streaming instabilities.

References in corpus (10)

• The stickiness of micrometer-sized water-ice particles
• How to form planetesimals from mm-sized chondrules and chondrule aggregates
• Can dust coagulation trigger streaming instability?
• Turbulence sets the length scale for planetesimal formation: Local 2D simulations of streaming instability and planetesimal formation
• Failed Growth at the Bouncing Barrier in Planetesimal Formation
• Seeding the Formation of Mercurys: An Iron-sensitive Bouncing Barrier in Disk Magnetic Fields
• A challenge for Martian lightning: Limits of collisional charging at low pressure
• Is There a Temperature Limit in Planet Formation at 1000 K?
• Quantitatively consistent, scale-spanning model for same-material tribocharging
• Composition and Size Dependent Sorting in Preplanetary Growth: Seeding the Formation of Mercury-like Planets

Cited by in corpus (9)

• Understanding planet formation using microgravity experiments
• Observation of bottom-up formation for charged grain aggregates related to pre-planetary evolution beyond the bouncing barrier
• The growth of super-large pre-planetary pebbles to an impact erosion limit
• Measuring Electric Dipole Moments of Trapped Sub-mm Particles
• Lifting of Tribocharged Grains by Martian Winds
• Forbidden planetesimals
• Ionizing Protoplanetary Disks in Pebble Collisions
• Clusters of tribocharged dust aggregates as pebbles in protoplanetary disks
• The Dissolution of Planetesimals in Electrostatic Fields