Related papers: Experiments on cometary activity: ejection of dust…
When comet nuclei approach the Sun, the increasing energy flux through the surface layers leads to sublimation of the underlying ices and subsequent outgassing that promotes the observed emission of gas and dust. The ejection of dust…
Our knowledge about the physical processes determining the activity of comets were mainly influenced by several extremely successful space missions, the predictions of theoretical models and the results of laboratory experiments. However,…
When viewed from Earth, most of what we observe of a comet is dust. The influence of solar radiation pressure on the trajectories of dust particles depends on their cross-section to mass ratio. Hence solar radiation pressure acts like a…
Comets have been invoked in numerous studies as a potentially important source of dust and gas around stars, but none has studied the thermo-physical evolution, out-gassing rate, and dust ejection of these objects in such stellar systems.…
Comets are made of volatile and refractory material and naturally experience various degrees of sublimation as they orbit around the Sun. This gas release, accompanied by dust, represents what is traditionally described as activity.…
The mechanism of dust emission from a cometary nucleus is still an open question and thermophysical models have problems reproducing outgassing and dust productions rates simultaneously. In this study, we investigate the capabilities of a…
We developed a thermophysical model for cometary nuclei, which is based upon the assumption that comets form by the gravitational instability of an ensemble of dust and ice aggregates. Under this condition, the tensile strength of the…
Ejection of large boulder-like debris is a vigorous form of cometary activity that is unlikely induced by water ice out-gassing alone but rather associated with the sublimation of super-volatile ices. Though perceived on several comets,…
Comets provide unique information about the physical and chemical properties of the environment in which the Solar system was formed. Understanding how cometary dust and ice evolve under the effect of sunlight is essential for constraining…
The process of cometary activity continues to pose a challenging question in cometary science. The activity modeling of comet 67P/Churyumov-Gerasimenko, based on data from the Rosetta mission, has significantly enhanced our comprehension of…
We use the gravitational instability formation scenario of cometesimals to derive the aggregate size that can be released by the gas pressure from the nucleus of comet 67P/Churyumov-Gerasimenko for different heliocentric distances and…
We extend an existing thermophysical activity model of comet 67P/Churyumov-Gerasimenko to include pressure buildup inside the pebbles making up the nucleus. We test various quantities of H$_{2}$O and CO$_{2}$, in order to simulate the…
Laboratory experiments show that dusty bodies in a gaseous environment eject dust particles if they are illuminated. We find that even more intense dust eruptions occur when the light source is turned off. We attribute this to a compression…
Reproducing the observed activity of comets with thermophysical models remains a primary challenge of cometary science. We use a pebble-based thermophysical model of gas-pressure build-up in the subsurface to reproduce the global emission…
The standard approach to obtaining knowledge about the properties of the surface layer of a comet from observations of gas production consists of two stages. First, various thermophysical models are used to calculate gas production for a…
The trajectories of dust particles ejected from a comet are affected by solar radiation pressure as a function of their ratios of radiation pressure cross section to mass. Therefore, a study on the orbital evolution of the particles caused…
Comets display with decreasing solar distance an increased emission of gas and dust particles, leading to the formation of the coma and tail. Spacecraft missions provide insight in the temporal and spatial variations of the dust and gas…
Some asteroids eject dust, producing transient, comet-like comae and tails; these are the active asteroids. The causes of activity in this newly-identified population are many and varied. They include impact ejection and disruption,…
In order to understand the origin and evolution of comets, one must decipher the processes that formed and processed cometary ice and dust. Cometary materials have diverse physical and chemical properties and are mixed in various ways.…
We present a model of cometary dust capable of simulating the dynamics within the first few tens of km of the comet surface. Recent measurements by the GIADA and COSIMA instruments on Rosetta show that the nucleus emits fluffy dust…