This particular star has shrunk so dramatically that the planetesimal
orbits within its sun's original radius.
"We can still learn some amazing new things about planetesimals
, primitive materials, solar system dynamics and [asteroid] composition."
The resulting paper, "Identification of a primordial asteroid family constrains the original planetesimal
population," appears in the August 3, 2017, online edition of Science.
The presence of aluminum-26 in a meteorite whose parent asteroid is known to have undergone early melting "helps buttress the case for aluminum-26 having been a major source of energy for planetesimal
heating," he adds.
However, for this specific journey, scientists believe a larger planetesimal
might have had some close encounters with other gas giants of the system, so close that the gravitational pull from the planets would have stretched and shredded the object into pieces.
"While we don't know the cause of the tumbling, we predict that it was most likely sent tumbling by an impact with another planetesimal
in its system, before it was ejected into interstellar space."
Their gravity then flung Uranus and Neptune out into the planetesimal
disc like bowling balls, causing the objects there to scatter like pins.
During this time there was only a rocky planetesimal
The high-resolution impact simulation shows parts of a large planetesimal
's core that penetrated all the way down below the Earth's crust.
These space rocks appear to have formed within the crust or mantle of a large planetesimal
and were later violently ejected into interplanetary space during a large impact.
For this study, scientists identified a new group of asteroids that can be traced back to the same planetesimal
from the early solar system, and it is (https://www.eurekalert.org/pub_releases/2017-08/aaft-h073117.php) one of the oldest families ever found.
The Trappist-1 system is named after the Transiting Planets and Planetesimals
Small Telescope (TRAPPIST) in Chile, which discovered two of the planets in the system in February 2016.