The pebbles/boulders size distributions on Sais: Rosetta's final landing site on comet 67P/Churyumov-Gerasimenko
Date Issued
2017
Author(s)
•
•
•
Mottola, S.
•
Hamm, M.
•
Da Deppo, V.
•
Penasa, L.
•
Kovacs, G.
•
Massironi, M.
•
Shi, X.
•
•
Güttler, C.
•
Oklay, N.
•
Vincent, J. B.
•
Toth, I.
•
Davidsson, B.
•
Naletto, G.
•
Sierks, H.
•
Barbieri, C.
•
Lamy, P. L.
•
Rodrigo, R.
•
Koschny, D.
•
Rickman, H.
•
Keller, H. U.
•
Agarwal, J.
•
A'Hearn, M. F.
•
Barucci, M. A.
•
Bertaux, J. L.
•
Bertini, I.
•
•
Debei, S.
•
De Cecco, M.
•
Deller, J.
•
El Maarry, M. R.
•
Fornasier, S.
•
Frattin, E.
•
Gicquel, A.
•
Groussin, O.
•
Gutierrez, P. J.
•
Höfner, S.
•
Hofmann, M.
•
Hviid, S. F.
•
Ip, W. H.
•
Jorda, L.
•
Knollenberg, J.
•
Kramm, J. R.
•
Kührt, E.
•
Küppers, M.
•
Lara, L. M.
•
Lazzarin, M.
•
Moreno, J. J. Lopez
•
Marzari, F.
•
Michalik, H.
•
Preusker, F.
•
Scholten, F.
•
Thomas, N.
Abstract
By using the imagery acquired by the Optical, Spectroscopic, and Infrared Remote Imaging System Wide-Angle Camera (OSIRIS WAC), we prepare a high-resolution morphological map of the Rosetta Sais final landing site, characterized by an outcropping consolidated terrain unit, a coarse boulder deposit and a fine particle deposit. Thanks to the 0.014 m resolution images, we derive the pebbles/boulders size-frequency distribution (SFD) of the area in the size range of 0.07-0.70 m. Sais' SFD is best fitted with a two-segment differential power law: the first segment is in the range 0.07-0.26 m, with an index of -1.7 ± 0.1, while the second is in the range 0.26-0.50 m, with an index of -4.2 +0.4/-0.8. The `knee' of the SFD, located at 0.26 m, is evident both in the coarse and fine deposits. When compared to the Agilkia Rosetta Lander Imaging System images, Sais surface is almost entirely free of the ubiquitous, cm-sized debris blanket observed by Philae. None the less, a similar SFD behaviour of Agilkia, with a steeper distribution above ∼0.3 m, and a flatter trend below that, is observed. The activity evolution of 67P along its orbit provides a coherent scenario of how these deposits were formed. Indeed, different lift pressure values occurring on the two locations and at different heliocentric distances explain the presence of the cm-sized debris blanket on Agilkia observed at 3.0 au inbound. Contrarily, Sais activity after 2.1 au outbound has almost completely eroded the fine deposits fallen during perihelion, resulting in an almost dust-free surface observed at 3.8 au.
Volume
469
Start page
S636
Issn Identifier
0035-8711
Ads BibCode
2017MNRAS.469S.636P
Rights
open.access
File(s)![Thumbnail Image]()
Loading...
Name
Pajola_SAIS_pebbles_boulders_SFD_final.pdf
Description
PDF editoriale
Size
4.26 MB
Format
Adobe PDF
Checksum (MD5)
d81304368a3697a81e57cc8c22b13d87