منابع مشابه
Dynamic molecular oxygen production in cometary comae
Abundant molecular oxygen was discovered in the coma of comet 67P/Churyumov-Gerasimenko. Its origin was ascribed to primordial gaseous O2 incorporated into the nucleus during the comet's formation. This thesis was put forward after discounting several O2 production mechanisms in comets, including photolysis and radiolysis of water, solar wind-surface interactions and gas-phase collisions. Here ...
متن کاملOrigin and production of C(1D) atoms in cometary comae
The abundance of carbon atoms in the metastable 1D state near the cometary nucleus provides an important diagnostic of one of the principal sources of carbon in the cometary coma. This quantity may be determined in two independent ways: measurement of 1D–1P fluorescence at 1931 Å and by prompt emission of the 1D–3P doublet at 9823/9850 Å. The latter is analogous to the [O i] λλ6300/6364 emissio...
متن کاملar X iv : a st ro - p h / 02 04 38 1 v 1 23 A pr 2 00 2 Chemical Processes in Cometary Comae
Recent developments in the chemical modelling of cometary comae are described. We discuss the cyanide chemistry and present new HCN observations of the recent comet C/2002 C1 (Ikeya-Zhang). The connection between interstellar and cometary organic molecules is discussed from the perspective of recent theories of interstellar gas-grain chemistry.
متن کاملAtomic Oxygen in the Comae of Comets
We report on the detection of atomic oxygen lines in the spectra of 8 comets. These forbidden lines are a result of the photodissociation of the parent oxygen-bearing species directly into an excited state. We used high resolution spectra obtained at the McDonald Observatory 2.7m telescope to resolve the cometary oxygen lines from the telluric oxygen lines and from other cometary emissions. We ...
متن کاملEEDF MEASUREMENTS AND EXCITATION PROCESSES IN THE VICINITY OF A HELIUM DISCHARGE CONSTRICTION
Axial distributions of plasma and floating potentials, electron number density and the electron energy distribution function (EEDF) have been measured in the double layer (DL) region of an He discharge constriction. Excitation processes in the constriction region are studied. Using a linearization method for the nonstationary balance equations and choosing appropriate discharge conditions, ...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1987
ISSN: 0074-1809
DOI: 10.1017/s0074180900154476