A Mechanism to Produce the Small Dust Observed in Protoplanetary Disks

Abstract

Small (sub)-micron dust is present over the entire lifetime of protoplanetary disks. As aggregation readily depletes small particles, one explanation might be that dust is continuously generated by larger bodies in the midplane and transported to the surface of the disks. In general, in a first step of this scenario, the larger bodies have to be destroyed again and different mechanisms exist with the potential to accomplish this. Possible destructive mechanisms are fragmentation in collisions, erosion by gas drag or light induced erosion. In laboratory experiments we find that the latter, light induced erosion by Knudsen compression and photophoresis, can provide small particles. It might be a preferred candidate as the dust is released into a low particle density region. The working principle of this mechanism prevents or decreases the likelihood for instant re-accretion or re-growth of large dense aggregates. Provided that there is a particle lift, e.g. turbulence, these particles might readily reach the surface of the disk.

7 pages, 6 figures

References in corpus (5)

• C2D Spitzer-IRS spectra of disks around T Tauri stars V. Spectral decomposition
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• Decimetre dust aggregates in protoplanetary discs
• Dust Ejection from Planetary Bodies by Temperature Gradients: Laboratory Experiments
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Cited by in corpus (9)

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• Photophoretic separation of metals and silicates: the formation of Mercury like planets and metal depletion in chondrites
• Erosion of dust aggregates
• From Planetesimals to Dust: Low Gravity Experiments on Recycling Solids at the Inner Edge of Protoplanetary Disks
• Photophoretic Strength on Chondrules. 2. Experiment
• Photophoresis boosts giant planet formation
• Photophoretic Strength on Chondrules 1: Modeling
• Selective Aggregation Experiments on Planetesimal Formation and Mercury-Like Planets
• Accretion through the inner edges of protoplanetary disks by a giant solid state pump