Jupiter birth dated through ancient molten rock droplets in meteorites

Researchers from Nagoya University and the Italian National Institute for Astrophysics (INAF) have determined the timing of Jupiter's formation by studying tiny molten rock spheres known as chondrules preserved in meteorites. These droplets formed 4.6 billion years ago when Jupiter's powerful gravity drove high-speed collisions between rocky and icy planetesimals.

When the planetesimals collided, their water instantly vaporized, generating explosive steam bursts that fragmented molten rock into droplets. These droplets solidified into chondrules, later incorporated into asteroids and preserved in meteorites. "When planetesimals collided with each other, water instantly vaporized into expanding steam. This acted like tiny explosions and broke apart the molten silicate rock into the tiny droplets we see in meteorites today," explained Professor Sin-iti Sirono of Nagoya University.

The team's computer simulations showed that chondrule production coincided with Jupiter's rapid accumulation of nebular gas, confirming that the planet's birth occurred about 1.8 million years after the solar system formed. Dr. Diego Turrini of INAF noted, "We compared the characteristics and abundance of simulated chondrules to meteorite data and found that the model spontaneously generated realistic chondrules. The model also shows that chondrule production coincides with Jupiter's intense accumulation of nebular gas to reach its massive size."

Although the study identifies when Jupiter formed, it also reveals that additional planets like Saturn likely triggered further chondrule production, explaining why meteorites contain chondrules of varying ages. This approach offers a new method to date planetary formation events, not only in our solar system but also around other stars.

Research Report:Chondrule formation by collisions of planetesimals containing volatiles triggered by Jupiter's formation