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Solar
Moon

Phobos

Orbital elements

Semi-major axis
0 AU
Eccentricity
0.0151
Inclination
1.09°
Orbital period
7.7 hours
Epoch · J2000
J2000

Physical properties

Mean radius
11 km
Mass
1.066 × 10¹⁶ kg
Density
1.876 g/cm³
Rotation period
7.65 hours

Visual & observation

Geometric albedo
0.071
Representative colour
#7A6A5F

Discovery & classification

Discovered by
Asaph Hall
Discovery date
18 August 1877

Sources