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The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy , it usually applies to planets or asteroids orbiting the Sun , moons orbiting planets, exoplanets orbiting other stars , or binary stars .
The long orbital period of Neptune means that the seasons last for forty Earth years. [109] Its sidereal rotation period (day) is roughly 16.11 hours. [ 12 ] Because its axial tilt is comparable to Earth's, the variation in the length of its day over the course of its long year is not any more extreme.
The accuracy of this calculation requires that the two dates chosen be along the elliptical orbit's minor axis and that the midpoints of each half be along the major axis. As the two dates chosen here are equinoxes, this will be correct when perihelion, the date the Earth is closest to the Sun, falls on a solstice. The current perihelion, near ...
Rotation period days: 25.38 Orbital period about Galactic Center [4] million years 225–250 Mean orbital speed [4] km/s: ≈ 220 Axial tilt to the ecliptic: deg. 7.25 Axial tilt to the galactic plane: deg. 67.23 Mean surface temperature: K: 5,778 Mean coronal temperature [5] K: 1–2 × 10 6: Photospheric composition H, He, O, C, Fe, S
All but the outer two are within Neptune-synchronous orbit (Neptune's rotational period is 0.6713 day or 16 hours [20]) and thus are being tidally decelerated. Naiad, the closest regular moon, is also the second smallest among the inner moons (following the discovery of Hippocamp), whereas Proteus is the largest regular moon and the second ...
At position b, Neptune gravitationally perturbs the orbit of Uranus, pulling it ahead of the predicted location. The reverse is true at a, where the perturbation retards the orbital motion of Uranus. John Couch Adams learned of these irregularities while still an undergraduate and became convinced of the perturbation hypothesis.
Clete orbits near Neptune's L 4 Lagrangian point about 60° ahead of Neptune and thus has the about same orbital period as Neptune. It orbits the Sun at a distance of 28.5–31.6 AU once every 164 years and 9 months (60,182 days; semi-major axis of 30.06 AU).
Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune. [ a ] Neptune orbits the Sun once every 164.8 years at an average distance of 30.1 astronomical units (4.50 × 10 9 km).