Halogens as tracers of protosolar nebula material in comet 67P/Churyumov–Gerasimenko

We report the first in situ detection of halogens in a cometary coma, that of 67P/ChuryumovGerasimenko. Neutral gas mass spectra collected by the European Space Agency’s Rosetta spacecraft during four periods of interest from the first comet encounter up to perihelion indicate that the main halogen-bearing compounds are HF, HCl and HBr. The bulk elemental abundances relative to oxygen are ~8.9 × 10⁻⁵ for F/O, ~1.2 × 10⁻⁴ for Cl/O and ~2.5 × 10⁻⁶ for Br/O, for the volatile fraction of the comet. The cometary isotopic ratios for ³⁷Cl/³⁵Cl and ⁸¹Br/⁷⁹Br match the Solar system values within the error margins. The observations point to an origin of the hydrogen halides in molecular cloud chemistry, with frozen hydrogen halides on dust grains, and a subsequent incorporation into comets as the cloud condensed and the Solar system formed

A thermal model of Rosetta/ROSINA/DFMS to assess the effects of solar illumination and thermal inertia of the mass spectrometer on mass spectra at 67P/Churyumov-Gerasimenko

International audienceThe coma composition of comet 67P/Churyumov-Gerasimenko is being analysed in detail with the high mass resolution Double Focussing Mass Spectrometer (DFMS) that is part of the ROSINA instrument suite on board of the Rosetta spacecraft. The Rosetta spacecraft - and DFMS in particular - experiences changing behaviour as the temperature varies with illumination and distance from the Sun. This contribution highlights these changes and their practical consequences for the interpretation of the DFMS mass spectra. A thermal model is presented that addresses thermal behaviour on a long time scale, related to instrument illumination and thermal gradients inside DFMS, and on a short time scale, related to transients after on/off cycling of the instrument and thermal inertia. Both issues adversely affect the problem of establishing a proper instrument mass calibration

Correcting peak deformation in Rosetta's ROSINA/DFMS mass spectrometer

International audienceThe Double Focusing Mass Spectrometer (DFMS), part of the ROSINA instrument package aboard the European Space Agency's Rosetta spacecraft visiting comet 67P/Churyumov-Gerasimenko, experiences minor deformation of the mass peaks in the high resolution spectra acquired for m/Z = 16, 17, and to a lesser extent 18. A numerical deconvolution technique has been developed with a two-fold purpose. A first goal is to verify whether the most likely cause of the issue, a lack of stability of one of the electric potentials in the electrostatic analyser, can indeed be held responsible for it. The second goal is to correct for the deformation, in view of the important species located around these masses, and to allow a standard further treatment of the spectra in the automated DFMS data processing chain

A thermal model of Rosetta/ROSINA/DFMS to assess the effects of solar illumination and thermal inertia of the mass spectrometer on mass spectra at 67P/Churyumov-Gerasimenko

International audienceThe coma composition of comet 67P/Churyumov-Gerasimenko is being analysed in detail with the high mass resolution Double Focussing Mass Spectrometer (DFMS) that is part of the ROSINA instrument suite on board of the Rosetta spacecraft. The Rosetta spacecraft - and DFMS in particular - experiences changing behaviour as the temperature varies with illumination and distance from the Sun. This contribution highlights these changes and their practical consequences for the interpretation of the DFMS mass spectra. A thermal model is presented that addresses thermal behaviour on a long time scale, related to instrument illumination and thermal gradients inside DFMS, and on a short time scale, related to transients after on/off cycling of the instrument and thermal inertia. Both issues adversely affect the problem of establishing a proper instrument mass calibration

A thermal model of Rosetta/ROSINA/DFMS to assess the effects of solar illumination and thermal inertia of the mass spectrometer on mass spectra at 67P/Churyumov-Gerasimenko

International audienceThe coma composition of comet 67P/Churyumov-Gerasimenko is being analysed in detail with the high mass resolution Double Focussing Mass Spectrometer (DFMS) that is part of the ROSINA instrument suite on board of the Rosetta spacecraft. The Rosetta spacecraft - and DFMS in particular - experiences changing behaviour as the temperature varies with illumination and distance from the Sun. This contribution highlights these changes and their practical consequences for the interpretation of the DFMS mass spectra. A thermal model is presented that addresses thermal behaviour on a long time scale, related to instrument illumination and thermal gradients inside DFMS, and on a short time scale, related to transients after on/off cycling of the instrument and thermal inertia. Both issues adversely affect the problem of establishing a proper instrument mass calibration

Halogens at Comet 67P/Churyumov-Gerasimenko observed by ROSINA-DFMS

International audienceSince August 2014, the Rosetta spacecraft has been studying the coma of comet 67P/Churyumov-Gerasimenko. The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) sensor DFMS is a double focussing mass spectrometer with a mass range 13-140 u/e. It is optimized for high mass resolution and large dynamic range and is a tool for the characterization of the volatiles in the coma. The hydrogen halides hydrogen fluoride (HF), hydrogen chloride (HCl) and hydrogen bromide (HBr) have been measured in the coma of comet 67P/Churyumov-Gerasimenko using DFMS. This presents the first time HBr has been detected in a comet. This presentation will focus on the abundance, variability and isotopic ratios of the halogens in the coma. Since comets retained information about the physical and chemical conditions of the protoplanetary disk from which they formed, these results may provide insights into the halogen chemistry in the early Solar System

A thermal model of Rosetta/ROSINA/DFMS to assess the effects of solar illumination and thermal inertia of the mass spectrometer on the mass spectra at 67P/Churyumov-Gerasimenko

info:eu-repo/semantics/nonPublishe

Halogens at Comet 67P/Churyumov-Gerasimenko seen with ROSINA-DFMS

International audienceThe Rosetta spacecraft has been studying the coma of comet 67P/Churyumov-Gerasimenko since August 2014 and will continue to do so up to the comet’s perihelion and for part of the voyage of the comet away from the Sun. The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) sensor DFMS is a double focussing mass spectrometer with a mass range 13–140 u/e. It is optimized for high mass resolution and large dynamic range and is an invaluable tool for the characterization of neutrals in the coma (1).Hydrogen fluoride (HF) and hydrogen chloride (HCl) are expected to be the main reservoirs of fluorine and chlorine wherever hydrogen is predominantly molecular in the interstellar medium (2). The strong depletion of these compounds in dense molecular clouds suggests freeze-out of these compounds onto grains in cold environments (3, 4). Therefore, one can expect that HCl and HF were also incorporated into comets.The halogens HF, HCl and also HBr (hydrogen bromide) have been measured using ROSINA-DFMS and this contribution will focus on the presence, abundance and variability of halogens in the coma of comet 67P. These results may provide insights on the halogen chemistry in the early solar nebula.(1) Balsiger et al., Space Science Reviews 128, 745.(2) Neufeld & Wolfire, ApJ 706, 1594.(3) Peng et al., ApJ 723, 218.(4) Emprechtinger et al., ApJ 756, 136