neptune was discovered by irregularities in the orbit of triton.
neptune was discovered by irregularities in the orbit of triton.
neptune was discovered by irregularities in the orbit of?
triton
gravitationally induced irregularities in uranus's observed orbit led eventually to the discovery of neptune in 1846, and presumed irregularities in neptune's orbit subsequently led to a search which did not find the perturbing object (it was later found to be a mathematical artefact caused by an overestimation of neptune's mass) but did find pluto in 1930. initially believed to be roughly the mass of the earth, observation gradually shrank pluto's estimated mass until it was revealed to be a mere five hundredth as large; far too small to have influenced neptune's orbit at all. in 1989, voyager 2 determined the irregularities to be due to an overestimation of neptune's mass.
definition of planet
many of the planetesimals are also implanted in various orbits beyond neptune's orbit during its migration. while neptune migrates outward several au, the hot classical kuiper belt and the scattered disk are formed as some planetesimals scattered outward by neptune are captured in resonances, undergo an exchange of eccentricity vs inclination via the kozai mechanism, and are released onto higher perihelion, stable orbits. planetesimals captured in neptune's sweeping 2:1 resonance during this early migration are released when an encounter with the ice giant causes its semi-major axis to jump outward, leaving behind a group of low-inclination, low-eccentricity objects in the cold classical kuiper belt with semi-major axes near 44 au. this process avoids close encounters with neptune allowing loosely bound binaries, including 'blue' binaries, to survive. an excess of low-inclination plutinos is avoided due to a similar release of objects from neptune's 3:2 resonance during this encounter. neptune's modest eccentricity following the encounter, or the rapid precession of its orbit, allows the primordial disk of cold classical kuiper belt objects to survive. if neptune's migration is slow enough following this encounter the eccentricity distribution of these objects can be truncated by a sweeping mean-motion resonances, leaving it with a step near neptune's 7:4 resonance. as neptune slowly approaches its current orbit, objects are left in fossilized high-perihelion orbits in the scattered disk. others with perihelia beyond neptune's orbit but not high enough to avoid interactions with neptune remain as a scattering objects, and those that remain in resonance at the end of neptune's migration form the various resonant populations beyond neptune's orbit. objects that are scattered to very large semi-major axis orbits can have their perihelia lifted beyond the influences of the giant planets by the galactic tide or perturbations from passing stars, depositing them in the oort cloud. if the hypothetical planet nine was in its proposed orbit at the time of the instability a roughly spherical cloud of objects would be captured with semi-major axes ranging from a few hundred to a few thousand au.
five-planet nice model