Water production rates from SOHO/SWAN observations of six comets: 2017–2020

Observations of molecules in comets

Comets are among the most primitive bodies of the Solar System, and their chemical composition is rich in information on the protosolar nebula and its possible connection with interstellar cloud chemistry. Comets are also a source of light atoms and probably of prebiotic organic molecules for the early Earth. We know better and better cometary volatiles through spectroscopy, mainly at infrared ...

IUE Observations of Faint Comets

Ultraviolet spectra of seven comets taken with the same instrument are presented. Comets P/Encke (1980), P/Tuttle (1980 h), P/Stephan-Oterma (1980 g), and Meier (1980 q) were observed during November-December 1980 with the International Ultraviolet Explorer (IUE) satellite observatory, while comets P/Borrelly (1980 i) and Panther (1980 u) were observed with IUE on 6 March 1981. The spectra of t...

On the Solar EUV Deposition in the Inner Comae of Comets with Large Gas Production Rates

Gas trapping in water ice at very low deposition rates and implications for comets

The effect of water ice formation temperature and rate of ice deposition on a cold plate on the amount of trapped argon (equivalent to CO), and the ratios of Ar/Kr/Xe trapped in the water ice were studied at 50, 27 and 22 K and at ice formation rates ranging over four orders of magnitude, from 10 1 to 10 5 m min . Contrary to our previous conclusions that cometary ices were formed at 50–60 K, w...

The Modern Role of Visual Observations of Comets

This paper reviews the role of past and future visual observations in cometary research. The strengths and limitations of visual observations are explored for the benefit of both investigators who might have to use them and observers who wish to make real contributions to the field. We consider the characteristics of the eye-brain combination as a detector and compare them with modem detectors....