Universe Guide

Proteus, Moon of Neptune

Proteus is a Moon that orbits round the planet Neptune. Its mass is estimated/calculated at being 50,355,259,352,065,700,000 kg. Its density has been calculated at being 1.3. Its volume is 38792386.

It was discovered in the year 1989 by S. Synnott, Voyager 2.

The orbital period, i.e. the period it takes to complete an orbit round Neptune is 1.12232 days. The figure is also known as the sidereel period. The figure comes from N.A.S.A..

The Equatorial Radius of the object is 210km. The value is the radius in km of the said object at the Equator.

The Escape Velocity of the object is 644 km/h. The Escape Velocity is the speed an object needs to be travelling in order to break free from the objects gravity. The larger an object is, the more velocity (speed) is needed to break free from the object.The Semi-Major Axis of the orbit is 117.647, which is the furthest point from the centre to the edge of an elliptical point.

The equatorial circumference of Proteus is 1319.5 km. The surface area of Proteus is 554,176.94. The surface gravity of the said item is 0.76. The Mean orbit velocity, that is the speed at which it orbits is 27450.70 km/h. The is the average distance in km of the object is from its parent 117646.00.

The orbital inclination, the angle at which Proteus orbits in relation to the orbital plane is 0.04 degrees. The orbital eccentricity is 0.0005, it is the degree at which Proteus orbits close to a circular (0) orbit as opposed to an elliptical (1) orbit.

Proteus is the largest moon that is not fully spherical in shape. Had the moon been slightly more massive, it would have been spherical. It is probably an asteroid that was captured from the Oort Cloud when it strayed too closely. It is the second largest of the Neptunian moons. The largest is Triton, which accounts for 95% of all objects that are currently in orbit round Neptune.

Discovery of Proteus

Proteus was only discovered when the Voyager 2 Space Probe flew by. A smaller moon, Nereid had been discovered 33 years earlier by a ground based telescope. Proteus is a dark moon, it hardly reflects any sunlight, in fact, it only reflects about 6% of the light it receives which goes someway to explaining why it took so long to spot.

it is named like all the other Neptunian moons after a Greek Mythological character with a connection to either Neptune or Poseidon, the god of the seas. Proteus was an old sea god whom was a herdsman for Poseidon's seals.

Proteus Facts

Mass (kg)50,355,259,352,065,700,000
Density (g/cm^3)1.3
Volume (km^3)38792386
Orbital DirectionPrograde, same as the parents direction
Year of Discovery1989
DiscovererS. Synnott, Voyager 2
Orbital Period (days)1.12232
Equatorial Radius (km)210
Escape Velocity (km/h)644
Semi-Major Axis (10^3 km)117.647
Equatorial Circumference (km)1319.5
Surface Area (km^2)554,176.94
Surface Gravity (m/s^2)0.76
Mean Orbit Velocity (km/h)27450.70
Average Orbit Distance (km)117646.00
Orbital Inclination (degrees)0.04
Orbital Eccentricity0.0005

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