What is the maximum distance a planet class body could exist?

Question

as part of our solar system?

Answer 1

What a good question. I would imagine it depends on the mass of the host star, the mass of the neighbouring stars and the distance between said stars. Newton's inverse square law tells us that gravity inversely proportional to the square of the distance between two masses. In other words, the "pull" of gravity is weaker the further you get from a large mass.

Depending on the mass of the host star, there must be a calculable distance where the gravity of other stars takes over and captures any planets.

Answer 2

Somebody with a physics background will give you a better answer but once the gravitational effect from the sun, and depending upon the mass of the planet, there will be a distance where the planet is not held in orbit.

Answer 3

Well, this isn't my field, but I found your query interesting.  The distance isn't the discerning factor, but the size of a planetary body.  I cannot give you a numerical distance out of hand, but it's generally thought to end with Kuiper belt, a loose ring of icy bodies circling beyond the farthest identified planet.  This is also generally the origin point (as far as I know) of much of the cometary matter that enters our solar system.

Answer 4

Isn't that under review now?  Some astronomers say Pluto is not a planet and others say it is.  Who decides?

Answer 5

If we assume that the mass of the Centauri system is about equal to ours, half the distance to Centauri mass center should be the limit. That makes it impossible for a planet to orbit our sun at a distance over 2 lightyears (about 20 000 billion km)