Spherical and ellipsoidal harmonic gravitational field models of bilobed comet 67P/Churyumov-Gerasimenko

The dataset contains normalized spherical and ellipsoidal harmonic coefficients up to degree 20 for the gravitational field of the bilobed comet 67P/Churyumov-Gerasimenko. The files correspond to four simulated mass distributions:

Homogeneous body.

Heterogeneous case ı: Different densities for Lobe 1 ("Body"), Lobe 2 ("Head"), and the Neck, each of which is uniform.

Heterogeneous case ıı: Stratification of the Lobes with progressively denser, ellipsoidal interiors; the Neck is uniform.

Heterogeneous case ııı: Mass compaction towards the Neck, represented as 1-D density increase across each Lobe; the Neck is uniform.

The spherical harmonic coefficients are for the global body and stored in the standard, four-column format.

The ellipsoidal harmonic coefficients are for the individual Lobes and stored degreewise in a flexible-width format. Those of degree n are arranged in ascending order into the (n+1)th row. The data structure in terms of degree and order, (n,m) for 0≤n≤20 and 1≤m≤2n+1, is as follows:

(0,1) (1,1)  (1,2)  (1,3)(2,1)  (2,2)  (2,3)  (2,4)  (2,5)  ⋮ ⋯  (20,40)  (20,41)

The definition of the Lobe-dependent local coordinate systems and the simulation parameters are provided in the accompanying pdf. Further details are given in the manuscript "Double ellipsoidal harmonic gravity field models for bilobed bodies: Example of comet 67P/Churyumov-Gerasimenko".