Opposition effect on comet 67P/Churyumov-Gerasimenko using Rosetta-OSIRIS images

Masoumzadeh, N.; Oklay, N.; Kolokolova, L.; Sierks, H.; Fornasier, S.; Barucci, M. A.; Vincent, J.-B.; Tubiana, C.; Güttler, C.; Preusker, F.; Scholten, F.; Mottola, S.; Hasselmann, P. H.; Feller, C.; Barbieri, C.; Lamy, P. L.; Rodrigo, Rafael; Koschny, D.; Rickman, H.; A’Hearn, M. F.; ... (2017). Opposition effect on comet 67P/Churyumov-Gerasimenko using Rosetta-OSIRIS images. Astronomy and astrophysics, 599(A11), A11. EDP Sciences 10.1051/0004-6361/201629734

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We aim to explore the behavior of the opposition effect as an important tool in optical remote sensing on the nucleus of comet 67P/Churyumov-Gerasimenko (67P), using Rosetta-OSIRIS images acquired in different filters during the approach phase, July-August 2014 and the close flyby images on 14 of February 2015, which contain the spacecraft shadow. Methods. We based our investigation on the global and local brightness from the surface of 67P with respect to the phase angle, also known as phase curve. The local phase curve corresponds to a region that is located at the Imhotep-Ash boundary of 67P. Assuming that the region at the Imhotep-Ash boundary and the entire nucleus have similar albedo, we combined the global and local phase curves to study the opposition-surge morphology and constrain the structure and properties of 67P. The model parameters were furthermore compared with other bodies in the solar system and existing laboratory study. Results. We found that the morphological parameters of the opposition surge decrease monotonically with wavelength, whereas in the case of coherent backscattering this behavior should be the reverse. The results from comparative analysis place 67P in the same category as the two Mars satellites, Phobos and Deimos, which are notably different from all airless bodies in the solar system. The similarity between the surface phase function of 67P and a carbon soot sample at extremely small angles is identified, introducing regolith at the boundary of the Imhotep-Ash region of 67P as a very dark and fluffy layer.

Item Type:

Journal Article (Original Article)

Division/Institute:

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

UniBE Contributor:

Rodrigo, Rafael and Thomas, Nicolas

Subjects:

500 Science > 520 Astronomy
600 Technology > 620 Engineering

ISSN:

0004-6361

Publisher:

EDP Sciences

Language:

English

Submitter:

Dora Ursula Zimmerer

Date Deposited:

20 Nov 2017 15:42

Last Modified:

26 Nov 2017 02:19

Publisher DOI:

10.1051/0004-6361/201629734

BORIS DOI:

10.7892/boris.106284

URI:

https://boris.unibe.ch/id/eprint/106284

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