Analysis of layering-related linear features on comet 67P/Churyumov-Gerasimenko. (arXiv:1901.00290v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Ruzicka_B/0/1/0/all/0/1">Birko-Katarina Ruzicka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Penasa_L/0/1/0/all/0/1">Luca Penasa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boehnhardt_H/0/1/0/all/0/1">Hermann Boehnhardt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pack_A/0/1/0/all/0/1">Andreas Pack</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dolives_B/0/1/0/all/0/1">Benoit Dolives</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Souvannavong_F/0/1/0/all/0/1">Fabrice Souvannavong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Remetean_E/0/1/0/all/0/1">Emile Remetean</a>
We analysed layering-related linear features on the surface of comet
67P/Churyumov-Gerasimenko (67P) to determine the internal configuration of the
layerings within the nucleus. We used high-resolution images from the OSIRIS
Narrow Angle Camera onboard the Rosetta spacecraft, projected onto the SHAP7
shape model of the nucleus, to map 171 layering-related linear features which
we believe to represent terrace margins and strata heads. From these curved
lineaments, extending laterally to up to 1925 m, we extrapolated the subsurface
layering planes and their normals. We furthermore fitted the lineaments with
concentric ellipsoidal shells, which we compared to the established shell model
based on planar terrace features. Our analysis confirms that the layerings on
the comet’s two lobes are independent from each other. Our data is not
compatible with 67P’s lobes representing fragments of a much larger layered
body. The geometry we determined for the layerings on both lobes supports a
concentrically layered, `onion-shell’ inner structure of the nucleus. For the
big lobe, our results are in close agreement with the established model of a
largely undisturbed, regular, concentric inner structure following a generally
ellipsoidal configuration. For the small lobe, the parameters of our
ellipsoidal shells differ significantly from the established model, suggesting
that the internal structure of the small lobe cannot be unambiguously modelled
by regular, concentric ellipsoids and could have suffered deformational or
evolutional influences. A more complex model is required to represent the
actual geometry of the layerings in the small lobe.
We analysed layering-related linear features on the surface of comet
67P/Churyumov-Gerasimenko (67P) to determine the internal configuration of the
layerings within the nucleus. We used high-resolution images from the OSIRIS
Narrow Angle Camera onboard the Rosetta spacecraft, projected onto the SHAP7
shape model of the nucleus, to map 171 layering-related linear features which
we believe to represent terrace margins and strata heads. From these curved
lineaments, extending laterally to up to 1925 m, we extrapolated the subsurface
layering planes and their normals. We furthermore fitted the lineaments with
concentric ellipsoidal shells, which we compared to the established shell model
based on planar terrace features. Our analysis confirms that the layerings on
the comet’s two lobes are independent from each other. Our data is not
compatible with 67P’s lobes representing fragments of a much larger layered
body. The geometry we determined for the layerings on both lobes supports a
concentrically layered, `onion-shell’ inner structure of the nucleus. For the
big lobe, our results are in close agreement with the established model of a
largely undisturbed, regular, concentric inner structure following a generally
ellipsoidal configuration. For the small lobe, the parameters of our
ellipsoidal shells differ significantly from the established model, suggesting
that the internal structure of the small lobe cannot be unambiguously modelled
by regular, concentric ellipsoids and could have suffered deformational or
evolutional influences. A more complex model is required to represent the
actual geometry of the layerings in the small lobe.
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