Related papers: Local manifestations of cometary activity
We show that the scattering phase functions of the coma and the nucleus of the comet 67P/Churyumov-Gerasimenko measured by the Rosetta/OSIRIS instrument can be reproduced by a particle model involving clustered densely packed…
Motion of many comets is affected by non-gravitational forces caused by outgassing from their surfaces. Outgassing also produces reactive torques resulting in cometary spin evolution. We propose that the two processes are correlated and…
We review the current state of knowledge of the long-term evolution of the small bodies that give rise to comets and exocomets, as well as their reservoirs. The active cometary phase is only transitory, and bodies that become comets pass…
Small bodies are capable of delivering essential prerequisites for the development of life, such as volatiles and organics, to the terrestrial planets. For example, empirical evidence suggests that water was delivered to the Earth by…
We carried out photometric and spectroscopic observations of comet 29P/Schwassmann-Wachmann 1 at the 6-m BTA telescope (SAO RAS, Russia) and the 1.6-m telescope of the National Laboratory for Astro-physics (LNA, Brazil) on February 20,…
We here study the transfer process of material from one hemisphere to the other (deposition of airfall material) on an active comet nucleus, specifically 67P/Churyumov-Gerasimenko. Our goals are to: 1) quantify the thickness of the airfall…
Gas-phase molecules in cometary atmospheres (comae) originate primarily from (1) outgassing by the nucleus, (2) sublimation of icy grains in the near-nucleus coma, and (3) coma (photo-)chemical processes. However, the majority of cometary…
Water ice-rich patches have been detected on the surface of comet 67P/Churyumov-Gerasimenko by the VIRTIS hyperspectral imager on-board the Rosetta spacecraft, since the orbital insertion in late August 2014. Among those, three icy patches…
Comet 67P/Churyumov-Gerasimenko (67P) was imaged with the 2m telescope at Mt. Wendelstein Observatory in the Alps. Coma and tail monitoring was performed during 51 nights between 22 August 2015 and 9 May 2016. The images through r and i…
We investigated three comets, which are active at large heliocentric distances, using observations obtained at the 6-m BTA telescope (SAO RAS, Russia) in the photometric mode of the focal reducer SCORPIO. The three comets,…
The ESA Rosetta mission has allowed an extensive in-situ study of comet 67P/Churyumov-Gerasimenko. In measurements performed by the ram gauge of the on-board COmet Pressure Sensor (COPS), features have been observed that deviate from the…
It is speculated that some weakly active comets may be transitional objects between active and dormant comets. These objects are at a unique stage of the evolution of cometary nuclei, as they are still identifiable as active comets, in…
A detailed study of comets active at large heliocentric distances (greater than 4 au) which enter the Solar System for the first time and are composed of matter in its elementary, unprocessed state, would help in our understanding of the…
The structure of cometary dust is a tracer of growth processes in the formation of planetesimals. Instrumentation on board the Rosetta mission to comet 67P/Churyumov- Gerasimenko captured dust particles and analysed them in situ. However,…
A mechanism is proposed to explain the outburst of comet 17P/Holmes based on; (a) oxidation of water within the porous surface of the comet nucleus to form hydrogen peroxide (H2O2) through exposure to UV radiation, to energetic solar-wind…
The observation of pits at the surface of comets offers the opportunity to take a glimpse into the properties and the mechanisms that shape a nucleus through cometary activity. If the origin of these pits is still a matter of debate,…
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,…
Ice naturally forms in the disordered or ``amorphous'' state when accreted from vapor at temperatures and pressures found in the interstellar medium and in the frigid, low density outer regions of the Sun's protoplanetary disk. It is…
We present a method to analyze images of the coma of 67P/Churyumov-Gerasimenko obtained using OSIRIS, the main imaging system onboard \textit{Rosetta}, where dust aggregates can be seen as bright tracks because of their relative velocity…
Context: The ionosphere of a comet is known to deflect the solar wind through mass loading, but the interaction is dependent on cometary activity. We investigate the details of this process at comet 67P using the Rosetta Ion Composition…