When it comes to making planets as big as Jupiter, Mother Nature has kept her recipe secret. But scientists believe they have finally cracked the mystery.
The conundrum centered on how the cores of planets as far away from the sun as Jupiter and Saturn had time to wrap themselves in giant blankets of gas, rather than migrate inward at an early stage, stifling their growth.
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The trick, new computer simulations show, is heat released by the planetary embryos themselves, triggering tidal forces in the surrounding gas and dust that offset the sun's gravitational pull.
Previous computer models didn't take tidal effects into consideration, astronomer Frederic Masset, with the National Autonomous University of Mexico, wrote in an email to Discovery News.
That idea stemmed from a realization that similar processes drive the migration of stars in compact regions at the center of galaxies.
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"A few years ago, after I gave a seminar at the University of Texas at Austin, I was asked by one of the researchers in the audience whether the luminosity of the stars in an AGN (Active Galactic Nuclei) could alter their migration.
"I initially thought that this would have no effect, but I realized afterward that tiny asymmetries in the heated disk in the immediate vicinity of the planet (or star, in an AGN) could potentially have huge effects on the tidal force. This is why I eventually decided to investigate the role that the heating due to planetesimal bombardment could have on planetary migration," Masset said.
The research brings computer models closer to explaining what is observed in the solar system and a roadmap for understanding planetary development around other stars.
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"We have learned of a new effect that may be important for understanding the architecture of planetary systems," astronomer Martin Duncan, with Queen's University, Kingston, Canada, told Discovery News.
The research "is only a first step," Masset added. "It shows that heating processes are of foreground importance in migration scenarios."
The study is published in this week's Nature.