Do you think that there could be a planet so big that stars orbit it?

Answer 1

Doubtful. Any planet with that much mass would collapse into itself and compress its core to a point where nuclear fusion commences. At which point you'd no longer have a planed; you'd have a star.

Answer 2

Depends what you call a planet, and what you call a star. The traditional definition of a planet is that it's something which goes around a star. The traditional definition of a star is something which generates (or at least once generated) its own energy by nuclear fusion.

If you accept the above definitions, then no, a planet can not have a star orbiting it (as a planet is something which orbits a star, not vice versa). Moreover, I'm not sure that if you took a planet like the Earth (made of rock, that is), and started adding mass to it (in the form of more rock, not in the form of hydrogen or even helium), that it would be able to hold itself up. At *some* point (I don't know what point exactly), it would fall in on itself and more or less become an odd kind of white dwarf, thus blurring the line between rocky object and star (because white dwarfs are still considered stars, though you could argue that they really aren't).

Of course, all this would require a *lot* of rock, and it would require very little hydrogen. If there were lots of hydrogren (or even helium), you'd probably get a fusion reaction, and end up with something that is basically a star (even if it had a rocky center). But hydrogen is extremely abundant in the universe as it currently exists. So having that happen would be very, very, *very* unlikely.

Answer 3

Planets don't orbit stars, and stars don't orbit planets. They both orbit their common centre of mass known as the Barycentre. This is one of the ways we can detect exoplanets by looking at the star's wobble as it orbits.

It just seems that a planet orbits its star because in our solar system the barycentre is IN the sun.

When you get to about 13 Jupiter masses, you start to form a brown dwarf (an object that started out as a star but its core became degenerate before nuclear reactions can start. Just bigger than this and you form a star.

So, if you had a planet just smaller than a brown dwarf, and a star just bigger, they would appear to orbit a point nearly directly between the two, and that's as close as you can get to a star appearing to orbiting a planet. But since they both orbit their barycentre then the question becomes nonsensical.

Hope that helps!

Answer 4

Stars and planets orbit each other. It's just that the star is so much more massive, that the planet's pull on the star is much harder to see - but it's there, that's how we find extrasolar planets.

A planet with a star noticably orbiting it would have to be more massive than the star - and anything more massive than a star is a star itself (unless it's a black hole). A planet massive enough to be a star will be a star, so you won't see any stars orbiting planets the same way planets orbit our sun.

Answer 5

it would seem that a planet could have a star that orbits it..however a planet IS a body that orbits a star..that in theory would change the status of a planet..so ummmm probably not..i believe that the star is formed first then the debris that orbits it collects to form the planets. unless the planet or moon is from another place in the galaxy and gets trapped by the gravitational pull of another body..but thats a different subj all together...

Answer 6

well, if the star is a white dwarfs then any planets orbit it will be about it's size or bigger. however, the reason one object orbiting another object is due to it's mass, not size. and in my example of white dwarfs; even though it is smaller, the density will still be higher than any planet, hence more massive. if any object is massive enough then it will start nuclear fusion and become a star

so to answer your question, it is not possible for a star to orbit a planet, but it is possible that a planet is bigger than then a star that it orbiting.

Answer 7

No. One of the defining features of a star is its mass. There is a certain critical mass needed to start a nuclear fusion chain reaction, at which point the body becomes a star. And since an orbiting object cannot have a greater mass than the object it orbits, no non-star would ever have a star in its orbit.

Answer 8

Possible. Not if the planet is mostly hydrogen, like all gas giants we know of, but if it was made of rock and iron it would have to be over a solar mass before it collapsed into a neutron ball, so small red dwarf stars could orbit it.

Answer 9

If the earth was as large as the sun, the compression at its core would be much greater causing a lot more heat to be generated changing the molecular structure of the iron into a gas, as the heat caused the atoms to cast off electrons, neutrons, and protons, shortly after it had melted the earth's crust. This of course would result in a lot more fusion and more heat eventually changing what was left of the earths surface into a gas, as the atoms cast off electrons, protons, and neutrons. One of the products of this process would be oxygen allowing the earth's surface to ignite. In short, the earth would become a star.

Answer 10

It isn't a matter of size actually.
Since in the whole universe there's no such thing as a central point, but it all depends on the chosen frame of reference by the observer, you don't have to look any further than good old planet earth. If your frame of reference is located on earth then you can say that the sun orbits it.