Early planet formation triggers planet offspring

December 07, 1999

Interaction between massive planets and the disks of gas and dust from which they formed are vital in determining the shape of planetary systems, suggest two former University of Toronto researchers.

In a paper to be published in the December issue of Nature, Philip Armitage and Brad Hansen, formerly of U of T's Canadian Institute of Theoretical Astrophysics, studied how early planet formation triggered the formation of other planets in developing solar systems.

"We're suggesting that it's the mass of the disk that influences the formation of planetary systems," says Armitage. "If the disk is lightweight, planet formation occurs fairly slowly - over 10 million years or so - and the result could look something like our own solar system. For a heavyweight disk, more violent processes can occur more quickly and lead to a very different-looking system of planets."

Using computer simulations, the researchers tested how a massive planet the size of Jupiter would interact with a massive disk, 10 times larger than the disk thought to have given rise to our own solar system. They found the extra gravitational force from the planet would cause parts of the disk to collapse and fragment into other planets. The resulting planets would also be gigantic, but would be mostly gaseous rather than solid like that of Earth.

According to Armitage and Hansen, their research indicates that there is an upper limit to the amount by which planets can grow. If the planets formed close together, the planetary system would become violently unstable - some planets would be ejected from the system and the remaining ones would be left with eccentric orbits.

"The paper provides a new way to understand how multiple planets could form in a relatively short space of time, roughly the first million years after the birth of the solar system," says Hansen. "The rapid creation of additional planets will result in competition during planet growth and so may explain why there appears to be a maximum mass for planets around other stars."

Whether habitable Earth-like planets can form and survive in such harsh environments and allow life to develop and grow remains unknown, say the researchers.

"This work, along with other theoretical explanations of planetary systems, suggests that planet formation can sometimes involve violent and chaotic processes that are different from those of our own early solar system," says Armitage. "We now know that the existence of planets themselves are common. However, conditions suitable for forming habitable planets - at least ones like the Earth - could still be rare."

Armitage is currently completing post-doctoral work at the Max-Planck-Institut for Astrophysik in Germany. Hansen is a Hubble post-doctoral fellow at Princeton University in the United States.
Janet Wong
U of T Public Affairs
(416) 978-6974

University of Toronto

Related Solar System Articles from Brightsurf:

Ultraviolet shines light on origins of the solar system
In the search to discover the origins of our solar system, an international team of researchers, including planetary scientist and cosmochemist James Lyons of Arizona State University, has compared the composition of the sun to the composition of the most ancient materials that formed in our solar system: refractory inclusions in unmetamorphosed meteorites.

Second alignment plane of solar system discovered
A study of comet motions indicates that the Solar System has a second alignment plane.

Pressure runs high at edge of solar system
Out at the boundary of our solar system, pressure runs high.

What a dying star's ashes tell us about the birth of our solar system
A UA-led team of researchers discovered a dust grain forged in a stellar explosion before our solar system was born.

What scientists found after sifting through dust in the solar system
Two recent studies report discoveries of dust rings in the inner solar system: a dust ring at Mercury's orbit, and a group of never-before-detected asteroids co-orbiting with Venus, supplying the dust in Venus' orbit.

Discovered: The most-distant solar system object ever observed
A team of astronomers has discovered the most-distant body ever observed in our solar system.

Discovery of the first body in the Solar System with an extrasolar origin
Asteroid 2015 BZ509 is the very first object in the Solar System shown to have an extrasolar origin.

First interstellar immigrant discovered in the solar system
A new study has discovered the first known permanent immigrant to our solar system.

A star disturbed the comets of the solar system in prehistory
About 70,000 years ago, when the human species was already on Earth, a small reddish star approached our solar system and gravitationally disturbed comets and asteroids.

Scientists detect comets outside our solar system
Scientists from MIT and other institutions, working closely with amateur astronomers, have spotted the dusty tails of six exocomets -- comets outside our solar system -- orbiting a faint star 800 light years from Earth.

Read More: Solar System News and Solar System Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.