Experiments on cometary activity: ejection of dust aggregates from a sublimating water-ice surface
arXiv:1811.09397 · doi:10.1093/mnras/sty3182
Abstract
The gas-driven dust activity of comets is still an unresolved question in cometary science. In the past, it was believed that comets are dirty snowballs and that the dust is ejected when the ice retreats. However, thanks to the various space missions to comets, it has become evident that comets have a much higher dust-to-ice ratio than previously thought and that most of the dust mass is ejected in large particles. Here we report on new comet-simulation experiments dedicated to the study of the ejection of dust aggregates caused by the sublimation of solid water ice. We find that dust ejection exactly occurs when the pressure of the water vapor above the ice surface exceeds the tensile strength plus the gravitational load of the covering dust layer. Furthermore, we observed the ejection of clusters of dust aggregates, whose sizes increase with increasing thickness of the ice-covering dust-aggregate layer. In addition, the trajectories of the ejected aggregates suggest that most of the aggregates obtained a non-vanishing initial velocity from the ejection event.
References in corpus (18)
- Rapid planetesimal formation in turbulent circumstellar discs
- Scaling forces to asteroid surfaces: The role of cohesion
- Free Collisions in a Microgravity Many-Particle Experiment. I. Dust Aggregate Sticking at Low Velocities
- Dust release and tensile strength of the non-volatile layer of cometary nuclei
- Evidence for the formation of comet 67P/Churyumov-Gerasimenko through gravitational collapse of a bound clump of pebbles
- Gravitational slopes, geomorphology, and material strengths of the nucleus of comet 67P/Churyumov-Gerasimenko from OSIRIS observations
- Outgassing of icy bodies in the Solar System - II. Heat transport in dry, porous surface dust layers
- Comets formed in solar-nebula instabilities! -- An experimental and modeling attempt to relate the activity of comets to their formation process (corrigendum included)
- Outgassing of icy bodies in the solar system - I. The sublimation of hexagonal water ice through dust layers
- Formation of pebble-pile planetesimals
- What drives the dust activity of comet 67P/Churyumov-Gerasimenko?
- Free Collisions in a Microgravity Many-Particle Experiment III: The Collision Behavior of sub-Millimeter-Sized Dust Aggregates
- Tensile Strength of 67P/Churyumov-Gerasimenko Nucleus Material from Overhangs
- Comet formation in collapsing pebble clouds. What cometary bulk density implies for the cloud mass and dust-to-ice ratio
- The role of pebble fragmentation in planetesimal formation I. Experimental study
- Submillimetre-sized dust aggregate collision and growth properties
- Radially resolved simulations of collapsing pebble clouds in protoplanetary discs
- Prevailing dust-transport directions on comet 67P/Churyumov-Gerasimenko
Cited by in corpus (6)
- Terrestrial deuterium-to-hydrogen ratio in water in hyperactive comets
- Understanding planet formation using microgravity experiments
- Diurnal variation of dust and gas production in comet 67P/Churyumov-Gerasimenko at the inbound equinox as seen by OSIRIS and VIRTIS-M on board Rosetta
- Ejection and Dynamics of Aggregates in the Coma of Comet 67P/Churyumov-Gerasimenko
- Dynamics and potential origins of decimeter-sized particles around comet 67P/Churyumov-Gerasimenko
- A Simulation Platform for Small Solar System Bodies' Gravity Using the Einstein-Elevator