Search for dissertations about: "Comets"

Showing result 1 - 5 of 19 swedish dissertations containing the word Comets.

2. 1. Gas Production in Distant Comets

   Author : Marcus Gunnarsson; F Peter Schloerb; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Comets; Radio Astronomy; Molecular Spectroscopy; Coma Models; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; astronomi; Astronomy;

   Abstract : Molecular spectroscopy at radio wavelengths is a tool well suited for studying the composition and outgassing kinematics of cometary comae. This is particularly true for distant comets, i.e. comets at heliocentric distances greater than a few AU, where the excitation of molecules is inefficient other than for rotational energy levels. READ MORE

4. 2. Thermophysical Modelling and Mechanical Stability of Cometary Nuclei

   Author : Björn Davidsson; Dina Prialnik; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Comets; Tidal physics; Light scattering; Radiative transfer; Thermophysics; Gas kinetics; Non-gravitational forces; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Theoretical Astrophysics; teoretisk astrofysik;

   Abstract : Comets are the most primordial and least evolved bodies in the Solar System. As such, they are unique sources of information regarding the early history of the Solar System. However, little is known about cometary nuclei since they are very difficult to observe due to the obscuring coma. READ MORE

5. 3. From meteors to space safety : dynamical models and radar measurements of space objects

   Author : Daniel Kastinen; Johan Kero; Asta Pellinen-Wannberg; Mats Holmström; Detlef Koschny; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Meteors; meteor shower; atmosphere; meteoroids; meteoroid stream; small-body dynamics; solar system; comets; asteroids; near-Earth objects; space safety; space debris; radar; MU; EISCAT;

   Abstract : Every day the Earth's atmosphere is bombarded by 10-200 metric tons of dust-sized particles and larger pieces of material from space called meteoroids. Dust and meteoroids come from parent bodies such as comets and asteroids, which are remnants from the formation of the solar system. READ MORE

6. 4. Low-energy ions around comet 67P/Churyumov-Gerasimenko

   Author : Sofia Bergman; Gabriella Stenberg Wieser; Martin Wieser; Gert Brodin; Stein Håland; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Low-energy ions; spacecraft charging; comets; 67P Churyumov-Gerasimenko; Rosetta; RPC-ICA; SPIS; diamagnetic cavity; field of view; plasma; space plasma physics; rymd- och plasmafysik; Space and Plasma Physics;

   Abstract : Low-energy ions play important roles in the formation of the plasma environment around a comet. Reliable ways of measuring these ions are therefore of high importance to fully understand the processes and dynamics of this environment. Unfortunately, low-energy ions are infamously difficult to detect. READ MORE

7. 5. Rosetta Observations of Plasma and Dust at Comet 67P

   Author : Fredrik Leffe Johansson; Anders Eriksson; Jan-Erik Wahlund; Nicolas André; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Rosetta; Comets; Plasma; Langmuir Probes; Dust; Spacecraft-plasma interaction; Electrostatic Probes; Rosetta; kometer; plasma; stoft; rymdfarkost-plasma växelverkan; Fysik med inriktning mot rymd- och plasmafysik; Physics with specialization in Space and Plasma Physics;

   Abstract : In-situ observations of cometary plasma are not made because they are easy. The historic ESA Rosetta mission was launched in 2004 and traversed space for ten years before arriving at comet 67P/Churyumov-Gerasimenko, which it studied in unprecedented detail for two years. READ MORE