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The mass of Phobos from Viking flybys
Author(s) -
Christensen E. J.,
Born G. H.,
Hildebrand C. E.,
Williams B. G.
Publication year - 1977
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl004i012p00555
Subject(s) - martian , spacecraft , satellite , geology , astrobiology , radiometric dating , mars exploration program , remote sensing , astronomy , physics
The mass of the Martian satellite Phobos has been determined by processing radiometric tracking data obtained from the Viking‐1 spacecraft during a series of 14 near encounters which occurred in February 1977. Distances of closest approach ranged from 89 to 213 km from the center of mass of the satellite. Our best estimate for the gravitational constant, GM, of Phobos is (6.6 ± 0.8) × 10 −4 km³/s². The corresponding density of Phobos based on a volume estimate of 4800 ± 960 km³ from Mariner 9 imaging is 2.0 ± 0.5 gm/cm³.