Astronomy Now Home
Home Magazine Sky Chart Resources Store

On Sale Now!

The April 2014 issue of Astronomy Now is on sale! Order direct from our store (free 1st class post & to UK addresses). The Astronomy Now iPad/iPhone editions are now available worldwide in the iTunes store.

Top Stories

Earthshine used to test life detection method
...By imagining the Earth as an exoplanet, scientists observing our planet's reflected light on the Moon with ESO's Very Large Telescope have demonstrated a way to detect life on other worlds...

Solid buckyballs discovered in space
...Astronomers using NASA’s Spitzer Space Telescope have detected a particular type of molecule, given the nickname “buckyball”, in a solid form for the first time...

Steamy water-world gets the Hubble treatment
...Hubble Space Telescope observations of a 7 Earth-mass planet find an unusual water-rich world swathed in a thick, steamy atmosphere...

Asteroids may reveal details of Jupiter's formation

Posted: September 14, 2009

Bookmark and Share

The asteroids Vesta and Ceres may have borne the brunt of Jupiter’s increasing influence in the early Solar System, according to new research being presented today at the European Planetary Science Congress (EPSC) in Potsdam, Germany.

NASA’s Dawn spacecraft will arrive at Vesta in 2011, and Ceres in 2015. They are the two largest asteroids in the Solar System; indeed, Ceres is classed as a dwarf planet and is 950 kilometres wide. According to Dr Diego Turrini and colleagues at the Italian National Institute for Astrophysics in Rome, if Jupiter formed from the bottom up then the asteroids should reveal this in the pattern of craters on their surface.

NASA's Dawn spacecraft will encounter both Ceres and Vesta during the next decade. Image: NASA/JPL.

Their reasoning works as follows: they described Jupiter’s formation in three phases, 1) the accretion of Jupiter’s core, 2) a rapid accumulation of gas from the solar nebula from which the stars and planets formed, and 3) a slower accretion of gas around four billion years ago. They then simulated how the increasing mass and gravity of Jupiter would affect the orbits of comets and asteroids, and how they collided with one another.

“We found that the stage of Jupiter’s development made a big difference on the speed of impacts and the origin of potential impactors,” says Turrini. “When Jupiter’s core approaches its critical mass, it causes a sharp increase in low velocity impacts from small, rocky bodies orbiting nearby to Vesta and Ceres. Once Jupiter’s core has formed and the planet starts to rapidly accrete gas, it deflects more distant objects onto a collision course with Ceres and Vesta and the impacts become more energetic.”

The latter stages of Jupiter’s construction also coincide with the Late Heavy Bombardment between 4.1 and 3.8 billion years ago, when the gas giants began migrating outwards, flinging comets and asteroids everywhere, bombarding the inner Solar System.

“If we see evidence of an underlying intense, uniform crater pattern [on Ceres and Vesta], it will support the theory that one or both of these minor planets formed during the final phases of Jupiter accretion,” says Turrini.

To find out more about EPSC, visit

Hubble Reborn
Hubble Reborn takes the reader on a journey through the Universe with spectacular full-colour pictures of galaxies, nebulae, planets and stars as seen through Hubble's eyes, along the way telling the dramatic story of the space telescope, including interviews with key scientists and astronauts.

The Planets
From tiny Mercury to distant Neptune and Pluto, The Planets profiles each of the Solar System's members in depth, featuring the latest imagery from space missions. The tallest mountains, the deepest canyons, the strongest winds, raging atmospheric storms, terrain studded with craters and vast worlds of ice are just some of the sights you'll see on this 100-page tour of the planets.

3D Universe
Witness the most awesome sights of the Universe as they were meant to be seen in this 100-page extravaganza of planets, galaxies and star-scapes, all in 3D!


© 2014 Pole Star Publications Ltd.