High-resolution shape models of Phobos and Deimos from stereophotoclinometry

Earth, Planets and Space

Table 5 Comparison of Phobos global shape models

	Ernst et al. (this study)	Gaskell 2011	Willner et al. 2014^e
Image sources	Viking Orbiter, Phobos 2, MOC, HRSC, SRC, HiRISE	Viking Orbiter, Phobos 2	Viking Orbiter, HRSC, SRC
Image number	2382	232	not available
Global model GSD (m)	18	36^a	100
Maplet DTM GSD^b (m)	10	60	n/a
Average radius^c (km)	11.08 ± 0.04	11.12	11.12
Best-fit ellipsoid (semi-major axis)	12.95 ± 0.04 × 11.30 ± 0.04 × 9.16 ± 0.03	12.84 × 11.19 × 9.22	12.82 × 11.17 × 9.20
Volume (km³)	5695 ± 32	5760	5742 ± 35
Surface area (km²)	1640 ± 8	1650	1640
Bulk density^d (kg/m³)	1861 ± 11	1840	1846 ± 12
Comparison to MOLA	− 4.0 m median difference 20.1 m RMS	2.3 m median difference 29.4 m RMS	− 5.8 m median difference 21.7 m RMS

^aGlobal model oversamples the maplet data
^bBest maplet GSD used to construct global model
^cComputed from an equivalent volume sphere
^dCalculated assuming GM from Pätzold et al. (2014)
^eValues for GSD and volume from Willner et al. 2014; others measured from the shape model or derived in the same manner as the Ernst et al (this study) and Gaskell models to enable direct comparison