Related papers: Radiative processes as diagnostics of cometary atm…
Comets hold the key to the understanding of our solar system, its formation and its evolution, and to the fundamental plasma processes at work both in it and beyond it. A comet nucleus emits gas as it is heated by the sunlight. The gas…
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.…
The composition of cometary ices provides key information on the thermal and chemical properties of the outer parts of the protoplanetary disk where they formed 4.6 Gy ago. This chapter reviews our knowledge of composition of cometary comae…
Deriving properties of cometary nuclei from coma data is of significant importance for our understanding of cometary activity and has implications beyond. Ground-based data represent the bulk of measurements available for comets. Yet, to…
The study of comets affords a unique window into the birth, infancy, and subsequent history of the solar system. There is strong evidence that comets incorporated pristine interstellar material as well as processed nebular matter, providing…
Molecular cations are present in various astronomical environments, most notably in cometary atmospheres and tails where sunlight produces exceptionally bright near-UV to visible transitions. Such cations typically have longer-wavelength…
A fundamental question in cometary science is whether the different dynamical classes of comets have different chemical compositions, which would reflect different initial conditions. From the ground or Earth orbit, radio and infrared…
The proposed CUBES spectrograph for ESO's Very Large Telescope will be an exceptionally powerful instrument for the study of comets. The gas coma of a comet contains a large number of emission features in the near-UV range covered by CUBES…
Transiting planets provide a unique opportunity to study the atmospheres of extra-solar planets. Radiative hydrodynamical models of the atmosphere provide a crucial link between the physical characteristics of the atmosphere and the…
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…
Most of our knowledge of the physical processes in distant plasmas is obtained through measurement of the radiation they produce. Here we provide an overview of the main collisional and radiative processes and examples of diagnostics…
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 Milky Way Galaxy is literally teeming with exoplanets; thousands of planets have been discovered, with thousands more planet candidates identified. Terrestrial-like planets are quite common around other stars, and are expected to be…
We present a study of the current state of knowledge concerning spacecraft operations and potential hazards while operating near a comet nucleus. Starting from simple calculations comparing the cometary coma environment to benign conditions…
Comets are pristine remnants of the Solar system, composed of dust and ice. They remain inactive and undetectable for most of their orbit due to low temperatures. However, as they approach the Sun, volatile materials sublimate, expelling…
While it may seem counterintuitive that X-ray astronomy should give any insights into low-temperature planetary systems, planets orbit stars whose magnetized surfaces divert a small fraction of the stellar energy into high energy products:…
X-ray emission traces the gaseous environments of radio sources. The medium must be present for jet confinement, but what are its influence on jet fuelling, dynamics, propagation, and disruption? The observational situation is both…
Studying the atmospheres of exoplanets is one of the most promising ways to learn about distant worlds beyond our solar system. The composition of an exoplanet's atmosphere can provide critical insights into its geology and potential…
Active comets have been detected in several exoplanetary systems, although so far only indirectly, when the dust or gas in the extended coma has transited in front of the stellar disk. The large optical surface and relatively high…
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…