ROSINA/DFMS capabilities to measure isotopic ratios in water at comet 67P/Churyumov–Gerasimenko

Hässig, Myrtha; Altwegg, Kathrin; Balsiger, Hans; Berthelier, J. J.; Calmonte, Ursina; Combi, M.; De Keyser, J.; Fiethe, B.; Fuselier, S. A.; Rubin, Martin (2013). ROSINA/DFMS capabilities to measure isotopic ratios in water at comet 67P/Churyumov–Gerasimenko. Planetary and space science, 84, pp. 148-152. Elsevier 10.1016/j.pss.2013.05.014

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The likelihood that comets may have delivered part of the water to Earth has been reinforced by the recent observation of the earth-like D/H ratio in Jupiter-family comet 103P/Hartley 2 by Hartogh et al. (2011). Prior to this observation, results from several Oort cloud comets indicated a factor of 2 enrichment of deuterium relative to the abundance at Earth. The European Space Agency’s Rosetta spacecraft will encounter comet 67P/Churyumov-Gerasimenko, another Jupiter-family comet of likely Kuiper belt origin, in 2014 and accompany it from almost aphelion to and past perihelion. Onboard Rosetta is the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) which consists of two mass spectrometers and a pressure sensor [Balsiger et al. 2007]. With its unprecedented mass resolution, for a space-borne instrument, the Double Focusing Mass Spectrometer (DFMS), one of the major subsystems of ROSINA, will be able to obtain unambiguously the ratios of the isotopes in water from in situ measurements in the coma around the comet. We will discuss the performance of this sensor on the basis of measurements of the terrestrial hydrogen and oxygen isotopic ratios performed with the flight spare instrument in the lab. We also show that the instrument on Rosetta is capable of measuring the D/H even in the very low density water background released by the spacecraft. This capability demonstrates that ROSINA should obtain very sensitive measurements of these ratios in the cometary environment. These measurements will allow detection of fractionation as function of the distance from the nucleus as well as fractionation due to mechanisms that are correlated with heliocentric distance.

Item Type:	Journal Article (Original Article)
Division/Institute:	08 Faculty of Science > Institute of Applied Physics 08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences 08 Faculty of Science > Physics Institute
UniBE Contributor:	Hässig, Myrtha, Altwegg, Kathrin, Balsiger, Hans, Calmonte, Ursina Maria, Rubin, Martin
Subjects:	600 Technology > 620 Engineering 500 Science > 530 Physics
ISSN:	0032-0633
Publisher:	Elsevier
Language:	English
Submitter:	Cléa Serpollier
Date Deposited:	19 Jun 2014 08:46
Last Modified:	05 Dec 2022 14:29
Publisher DOI:	10.1016/j.pss.2013.05.014
URI:	https://boris.unibe.ch/id/eprint/44223