Capturing planets

May 22, 2012
Capturing planets
Drawings of Pluto and its moon Charon. The masses of the two objects are so similar (only a factor of 10 different) that some astronomers think of them as a binary system. New simulations predict that there may be free floating binary planets in space. Credit: NASA/JPL

(Phys.org) -- The discovery of planets around other stars has led to the realization that alien solar systems often have bizarre features - at least they seem bizarre to us because they were so unexpected. For example, many systems have giant planets closer to their star than Mercury is to the Sun, while other have the opposite - giant planets more than ten times farther way from their star than Jupiter is from our Sun. Astronomers think they understand how planets could end up close to the star: they gradually drift in from more customary orbits. But how can planets end up so far away?

A new theoretical study by CfA astronomer Hagai Perets and his colleague proposes a possible answer: the distant planets are not part of the original - they were captured by the star. Astronomers know that there are many so-called "free floating planets" in space - planets that have been tossed out of their original solar system by a random gravitational encounter with another planet. Some of these orphan planets have recently been detected.

The scientists calculated that it would be possible for a star to capture one of these orphans if the conditions were right; namely, if the star and planet happen to pass close to each other with only a small velocity difference, and if there are no other massive bodies nearby to interfere with the "adoption." They ran a series of to test all these and other possibilities, and they found not only that such a capture was possible, but that a star could even capture several orphan planets.

In fact, they found that sometimes two free floating planets could capture one another and form a binary planet. None of these binaries has yet been seen, although some astronomers think that since Pluto and its moon Charon have such similar masses they are a , although not necessarily one that was captured.

The new results seem to offer a reasonable, if exotic, explanation for some of the complex planetary configurations that have been discovered, and they remind us that nature is full of surprises.

Explore further: Professional and amateur astronomers join forces

Related Stories

Some stars capture rogue planets

Apr 17, 2012

(Phys.org) -- New research suggests that billions of stars in our galaxy have captured rogue planets that once roamed interstellar space. The nomad worlds, which were kicked out of the star systems in which ...

New planet discovered in Trinary star system

Jul 14, 2011

Until recently, astronomers were highly skeptical of whether or not planets should be possible in multiple star systems. It was expected that the constantly varying gravitational force would eventually tug ...

When stars play planetary pinball

Feb 08, 2012

Many of us remember playing pinball at the local arcade while growing up; it turns out that some stars like it as well. Binary stars can play tug-of-war with an unfortunate planet, flinging it into a wide ...

'Hot Jupiter' planets unlikely to have moons

Aug 23, 2010

(PhysOrg.com) -- Planets of the major type so far found outside our solar system are unlikely to have moons, according to new research reported in the August 20 issue of The Astrophysical Journal Letters.

New look at HD 10180 shows it might have nine planets

Apr 09, 2012

(Phys.org) -- Astronomer Mikko Tuomi of the University of Hertfordshire, has found after looking at data regarding the solar system surrounding the star HD 10180, that it likely has nine planets making it ...

Recommended for you

Professional and amateur astronomers join forces

14 hours ago

(Phys.org) —Long before the term "citizen science" was coined, the field of astronomy has benefited from countless men and women who study the sky in their spare time. These amateur astronomers devote hours ...

A star's early chemistry shapes life-friendly atmospheres

Apr 23, 2014

Born in a disc of gas and rubble, planets eventually come together as larger and larger pieces of dust and rock stick together. They may be hundreds of light-years away from us, but astronomers can nevertheless ...

User comments : 5

Adjust slider to filter visible comments by rank

Display comments: newest first

foofighter
4.2 / 5 (10) May 22, 2012
i cant wait till the voice of our generation, kanye...err kevinrtrs - comes in here and tells us about how bogus these simulations are and how its only due to the glory and wisdom of Christ that these planetary systems have such configurations. Amen Halleluyah!
Russkiycremepuff
1 / 5 (3) May 22, 2012
"A new theoretical study by CfA astronomer Hagai Perets and his colleague proposes a possible answer: the distant planets are not part of the original stellar system - they were captured by the star."

Another story that "proposes a possible answer". Possible answer is not same as definite answer. It seems that almost everything in cosmology is "up in the air", or, we may find out some day if true, but do not hold your breath in the meantime. (laughing)
eachus
2 / 5 (1) May 22, 2012
The article associates two possibly unrelated things: Free-floating binary planets, and the Pluto-Charon system.

But perhaps they are related? Pluto may have captured a free-floating object resulting in its' unusual orbit for a Kuiper belt member.
Russkiycremepuff
1 / 5 (2) May 22, 2012
I see that kaasinees has got me again with one rating. I suppose he has nothing better to do. I have seen that he does it to others also, and for no good reason. It could be a strange display of power? He is not well liked and that may have turned him into crank.
Yes, and in that case, which is the real moon, Pluto or Charon? That would depend on, I suppose, which one was captured by the other. Since Pluto is no longer full planet, either one could be a moon.
kevinrtrs
1.7 / 5 (6) May 29, 2012
i cant wait till the voice of our generation, kanye...err kevinrtrs - comes in here and tells us about how bogus these simulations are and how its only due to the glory and wisdom of Christ that these planetary systems have such configurations. Amen Halleluyah!

The simulations are not bogus - they're man's attempt to come up with an explanation for things that exist in a way that they have not observed happening. What tends to be bogus is that after observing the outcomes, people then jump to shouting that that is in fact how it happened, without mentioning the simulation in any way.

This article illustrates one point very clearly: we cannot see back into the past, especially the past that concerns the origin of everything. Alas, there is also no current occurrences of such phenomena to observe, therefore, simulations are required.

To make the point stick - who says that there ever was a big bang in reality? No one was there to see and record such. Who knows it wasn't created?

More news stories

Habitable exoplanets are bad news for humanity

Last week, scientists announced the discovery of Kepler-186f, a planet 492 light years away in the Cygnus constellation. Kepler-186f is special because it marks the first planet almost exactly the same size as Earth ...

Professional and amateur astronomers join forces

(Phys.org) —Long before the term "citizen science" was coined, the field of astronomy has benefited from countless men and women who study the sky in their spare time. These amateur astronomers devote hours ...

Kazakh satellite to be launched into orbit

Kazakhstan's first-ever Earth observation satellite is to be fired into orbit next week from the European spaceport in Kourou in French Guiana, launch company Arianespace said.

Genetic code of the deadly tsetse fly unraveled

Mining the genome of the disease-transmitting tsetse fly, researchers have revealed the genetic adaptions that allow it to have such unique biology and transmit disease to both humans and animals.

Ocean microbes display remarkable genetic diversity

The smallest, most abundant marine microbe, Prochlorococcus, is a photosynthetic bacteria species essential to the marine ecosystem. An estimated billion billion billion of the single-cell creatures live i ...