Strange Uranus-size alien planet could be trapped in the edge of Solar System

‘One in every 200-3000 stars’ could host a planet in outer edge of its solar system, researchers say

Scientists have predicted that there could be large planets the size of Jupiter or Uranus likely trapped at the edge of our solar system, much farther than the hypothetical planet X.

Such a planet from outside the Solar System could be trapped in the Oort Cloud – a theoretical shell of debris marking the gravitational edge of the Sun and its planets.

Researchers, including those from CNRS in France, say there could be more interstellar objects in this edge of the Solar System than previously thought.

Scientists ran complex computer simulations to assess how solar systems tend to cast off large planets, and also how a planetary system could catch one such “orphan” planet.

While a cast-off planet requires a kinetic energy threshold to leave the pull of its star, it also needs a significant amount of energy for another star system to trap it in.

Simulations suggested that a tiny fraction of such celestial encounters may end up with a star’s gravitational field catching a cast-away “orphan” planet and claiming it as its own.

They say this is more likely to happen when such a planet drifts close to a star system’s outer edge Oort cloud.

With up to a tenth of a star’s original planets likely to be cast out into deep space, scientists say there is a 7 per cent chance of our solar system capturing an ice giant planet like Uranus in the Oort cloud.

Researchers estimate that “one in every 200-3000 stars could host an Oort cloud planet.”

However, they say this prediction is likely an overestimate as the estimate does not account for instabilities that take place at the early stages of a solar system that could affect its star birth cluster, or planet stripping from passing stars.

“If the Solar System’s dynamical instability happened after birth cluster dissolution, there is an about 7 per cent chance that an ice giant was captured in the Sun’s Oort cloud,” scientists wrote in the study.

Based on the analysis, they say Oort Cloud planets at the edge of the Solar System are more likely to be adopted from interstellar space rather than being an offspring of the Sun.