planetesimal


Also found in: Dictionary, Thesaurus, Wikipedia.

planetesimal

[‚plan·ə′tes·ə·məl]
(astronomy)
One of the rocky bodies, of the order of 1 mile (1.6 kilometer) in diameter, that are believed to have formed in the protosolar nebula, and whose accretion formed the rocky cores of the larger planets.
References in periodicals archive ?
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 disk.
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.