The phase function and density of the dust observed at comet 67P/Churyumov–Gerasimenko

Fulle, Marco; Bertini, I; Della Corte, V; Güttler, C; Ivanovski, S; La Forgia, F; Lasue, J; Levasseur-Regourd, A C; Marzari, F; Moreno, F; Mottola, S; Naletto, G; Palumbo, P; Rinaldi, G; Rotundi, A; Sierks, H; Barbieri, C; Lamy, P L; Rodrigo, R; Koschny, D; ... (2018). The phase function and density of the dust observed at comet 67P/Churyumov–Gerasimenko. Monthly notices of the Royal Astronomical Society, 476(2), pp. 2835-2839. Oxford Academic 10.1093/mnras/sty464

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The OSIRIS camera onboard Rosetta measured the phase function of both the coma dust and the nucleus. The two functions have a very different slope versus the phase angle. Here, we show that the nucleus phase function should be adopted to convert the brightness to the size of dust particles larger than 2.5 mm only. This makes the dust bursts observed close to Rosetta by OSIRIS, occurring about every hour, consistent with the fragmentation on impact with Rosetta of parent particles, whose flux agrees with the dust flux observed by GIADA. OSIRIS also measured the antisunward acceleration of the fragments, thus providing the first direct measurement of the solar radiation force acting on the dust fragments and thus of their bulk density, excluding any measurable rocket effect by the ice sublimation from the dust. The obtained particle density distribution has a peak matching the bulk density of most COSIMA particles, and represents a subset of the density distribution measured by GIADA. This implies a bias in the elemental abundances measured by COSIMA, which thus are consistent with the 67P dust mass fractions inferred by GIADA, i.e. (38 ± 8) per cent of hydrocarbons versus the (62 ± 8) per cent of sulphides and silicates.

Item Type:

Journal Article (Original Article)

Division/Institute:

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

UniBE Contributor:

Thomas, Nicolas

Subjects:

500 Science > 520 Astronomy
600 Technology > 620 Engineering

ISSN:

0035-8711

Publisher:

Oxford Academic

Language:

English

Submitter:

Dora Ursula Zimmerer

Date Deposited:

15 May 2018 09:55

Last Modified:

22 Mar 2019 11:25

Publisher DOI:

10.1093/mnras/sty464

BORIS DOI:

10.7892/boris.116507

URI:

https://boris.unibe.ch/id/eprint/116507

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