I want to know does a planet have to orbit a star?

Question

i would assume that a planet is anything that has a atmesphere, and everything else is either a moon, or space garbage. I'm pretty sure there bodys some where in our universe that are large, and has a atmosphere, that doesnt orbit a star, but thats my belief

Answer 1

Hi. Usually, but a planet can have its orbit disrupted by a passing star, say, and leave its original orbit.

Answer 2

Yes you heard correctly. Of the 205 extra-solar planets so far discovered (and they are finding them at a rate of 20 a year now) two are free-floating (the first was discovered in 2004 with a mass 3 x Jupiter's mass) and there are several that orbit two or three stars.

First to be discovered in 1993 was PSR B1620-26c orbiting a pulsar and a white dwarf.

Astronomers have recently detected a planet in a relatively tight triple star system, a finding that challenges current theories of planetary formation. The planet, a gas giant slightly larger than Jupiter, orbits the main star of the HD 188753 system, in the constellation Cygnus, and is hence known as HD 188753 Ab. The stellar trio (yellow, orange, and red) is about 149 light years away.

The planet orbits the main star (HD 188753 A) about once every 3.3 days, at a distance of about a twentieth the distance between Earth and the Sun. The other two stars whirl tightly around each other in 156 days, and circle the main star every 25.7 years at a distance from the main star that would put them between Saturn and Uranus in our own Solar system.

The latter stars call into question the leading hot Jupiter formation theory, which holds that these planets form at "normal" distances and then migrate inward through some debatable mechanism. Such migration could not have occurred here, since the outer star pair would have disrupted outer planet formation.

Answer 3

It is actually not possible for a planet to be born and stay away from a star... to do so they would have to have been created and then actually fly out of the orbit of the star from which it was created, but then it would become a comit, may it large or small, until at one point it will eaither smash into a planitary system, another comit, or a star, and become part of said body. (Though the planet could take so long to reach another system, it is nearly uncomprehensible to the human existance of a mear 70-80 years.

Answer 4

It has to orbit the sun. the new definition is: "a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a ... nearly round shape, and has cleared the neighborhood around its orbit."

There is no universal definition to cover extrasolar planets (planets that orbit other stars) yet

Answer 5

Large planets have been found that are failed stars that orbit each other. They didn't have enough mass to trigger the fusion of hydrogen and start to shine. But they are very large. Larger than Jupiter.

Answer 6

I am not sure under the new definition. In theory, there are lone planets that have been ejected from their orbits, but I don't even think one has been observed yet.

Answer 7

I would say there may be planets out there that aren't... Yet.
I think the great gravity exerted by stars will eventualy pull any wayward objects out there into their orbits eventualy.

Answer 8

i would say so. note the last sentence.

plan·et (plăn'ĭt) pronunciation
n.

1. A nonluminous celestial body larger than an asteroid or comet, illuminated by light from a star, such as the sun, around which it revolves.

Answer 9

yes, other wise it is just wandering space debris. Planets by deffintion have to orbit stars.

Answer 10

anything big with a gravitational pull strong enough or it would just float through space