Assessment of detectability of neutral interstellar deuterium by IBEX observations

Kubiak, M. A.; Bzowski, M.; Sokół, J. M.; Möbius, E.; Rodriguez Moreno, Diego Francisco; Wurz, Peter; McComas, D. J. (2013). Assessment of detectability of neutral interstellar deuterium by IBEX observations. Astronomy and astrophysics, 556(A39), A39. EDP Sciences 10.1051/0004-6361/201321166

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Context. The abundance of deuterium in the interstellar gas in front of the Sun gives insight into the processes of filtration of neutral interstellar species through the heliospheric interface and potentially into the chemical evolution of the Galactic gas. Aims: We investigate the possibility of detection of neutral interstellar deuterium at 1 AU from the Sun by direct sampling by the Interstellar Boundary Explorer (IBEX). Methods: Using both previous and the most recent determinations of the flow parameters of neutral gas in the local interstellar cloud (LIC) and an observation-based model of solar radiation pressure and ionization in the heliosphere, we simulated the flux of neutral interstellar D at IBEX for the actual measurement conditions. We assessed the number of interstellar D atom counts expected during the first three years of IBEX operation. We also simulated the observations expected during an epoch of high solar activity. In addition, we calculated the expected counts of D atoms from the thin terrestrial water layer covering the IBEX-Lo conversion surface, sputtered by neutral interstellar He atoms. Results: Most D counts registered by IBEX-Lo are expected to come from the water layer, exceeding the interstellar signal by 2 orders of magnitude. However, the sputtering should stop once the Earth leaves the portion of orbit traversed by interstellar He atoms. We identify seasons during the year when mostly the genuine interstellar D atoms are expected in the signal. During the first 3 years of IBEX operations about 2 detectable interstellar D atoms are expected. This number is comparable to the expected number of sputtered D atoms registered during the same time intervals. Conclusions: The most favorable conditions for the detection occur during low solar activity, in an interval including March and April each year. The detection chances could be improved by extending the instrument duty cycle, say, by making observations in the special deuterium mode of IBEX-Lo.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences

UniBE Contributor:

Rodriguez Moreno, Diego Francisco and Wurz, Peter

Subjects:

500 Science > 530 Physics

ISSN:

0004-6361

Publisher:

EDP Sciences

Language:

English

Submitter:

Cléa Serpollier

Date Deposited:

11 Jul 2014 12:18

Last Modified:

26 Jun 2016 01:48

Publisher DOI:

10.1051/0004-6361/201321166

URI:

https://boris.unibe.ch/id/eprint/44741

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