Small celestial bodies violently collide and fuse to form planetesimals
Past simulations have tracked the trajectories of these planetesimals
and showed they wind up forming the Kuiper belt of icy debris where Pluto sits, some of the distant satellites of Jupiter and Saturn, and Trojan asteroids, bodies that share Jupiter's orbit but are centred at two points ahead of and behind the planet.
They slowly migrated inwards, Uranus and Neptune switching places, and the planetesimals
were scattered outwards.
A massive planet in an inclined orbit gravitationally attracts small bodies of rock and/or ice, called planetesimals
, from the main disk, and moves them into an orbit aligned with that of the planet.
The international team merged the numerous observations made with the use of three telescopes at European Southern Observatory's La Silla and Paranal observing sites in Chile: the Very Large Telescope, New Technology Telescope and TRAPPIST (TRAnsiting Planets and PlanetesImals
Small Telescope) as well as the data from other small telescopes in South America.
If the migration lasted only a million years, it could mean that the planetesimals
in the disk were particularly abundant and had circular orbits.
Asteroids are referred to as planetesimals
-- tiny seeds that were denied the chance to accrete into anything larger.
We see dust disks - presumably the primordial planet-forming material - around a whole load of stars, and we see planets, but we don't see much of the stuff in between: the asteroid-like planetesimals
and the comets.
The team, led by Jose Luis Ortiz (Instituto de Astrofisica de Andalucia, CSIC, Spain), combined multiple observations using three telescopes at ESO's La Silla and Paranal observing sites in Chile-the Very Large Telescope (VLT), New Technology Telescope (NTT), and TRAPPIST (TRAnsiting Planets and PlanetesImals
Small Telescope) -- with data from other small telescopes in South America, to look at Makemake as it passed in front of a distant star.
In addition to comets, asteroid-size planetesimals
containing water with less deuterium could have contributed to the late veneer, says Ozernoy.
In this model, primordial dust accumulates into mile-sized planetesimals
that then coalesce into full-fledged planets.
These bodies, called planetesimals
, may grow large enough to form planets as massive as Jupiter.