The small planet has an Earth-like crust

Small planets are rocks moving around the outer space, and scientists think their small size limits the type of rock that can form in the shell. But two newly discovered meteorites can give new insights into the formation and evolution of these small planets.

Researchers from Carnegie Institute, the University of Maryland, and the University of Tennessee published in the January 8 issue of Nature that these meteorites are fragments of ancient small planets containing Feldspar-rich rocks called is andexit. Similar rocks are from Earth, which makes these specimens the first case found in the Solar System.

Two meteorite masses were discovered in the Antarctic Meteorite Search Program (ANSMET) 2006/2007 in the icy area of ​​Antarctica called Graves Nunatak.These meteorites, known as GRA 06128 and GRA 06129, were immediately identified as completely different from the previously known meteorites.

A picture of the GRA 06129 meteorite, found in the frozen area of ​​Graves Nunatak in Antarctica, during a field trip to ANSMET 2006/2007.GRA 06129 and 06128 GRA meteorite, are seedless meteorites with chemical composition unlike any materials ever found in Thai Duong Hua.(Photo: Program for finding Antarctic meteorites (PI - Ralph Harvey, Case Western Reserve University)

James Day, lead author of the University of Maryland study, said: 'The most amazing thing is that these rocks have the same chemical composition as the seedless continental crust of the Earth - forming the ground. below us. There have never been any such asteroids ever known. '

Seedless rock is a kind of flint found on Earth in areas where stratigraphic collisions collide and create nondis luear, such as the Andes. Meteorite-filled meteorites are thought to undergo large-scale processes such as stratigraphic tectonics to concentrate the necessary chemicals. With this view, the researchers believe that these meteorites are fragments of a planet or of the Moon, not a small planet. However, the oxygen isotope analysis of meteorites by Douglas Rumble carried out the Carnegie Institute's Geophysical Laboratory to eliminate that possibility.

Rumble said: 'Some solar system objects include meteorites, planets, moons, and small planets with their own oxygen isotope indicators. By analyzing the rate of 160-170-180 we can know a meteorite coming from Sao Hao, the Moon or a small planet . An extensively studied object is the small planet 4 Vesta. In most cases the actual position of the mother object is not known, but a certain group of meteorites may come from the same maternal body based on the isotope ratio even when the position of the maternal object Not known. When the rate of meteorites is drawn on the chart, the results are parallel lines back and forth. The GRA 06128 meteorite and GRA 06129, and some similar meteorites called brachinites, lie beneath the Earth-Moon rock and almost coincide with meteorites from 4 Vesta '.

The age of these meteorites, more than 4.5 billion years old, shows that they formed very soon after the birth of the solar system . What shows them is less likely to come from the surface of a planet. Chemical markers of some rare metals, especially osmium, in meteorites also show their origin as a small planet.

The researchers theorized that the small planet has a diameter of more than 100km, enough to keep the heat of the puzzle causing the small planet's rock to melt partially, not completely. The small planet is still undifferentiated, but the melting part erupts into the small meteorite faces to form a seedless crust.

Day said: 'Our findings illustrate the formation of a planet-like seedless crust that appears with other processes rather than stratigraphic tectonics. This finding could bring new insights into the formation of planetary shells, including the Earth, in very early stages. '

The research was funded by NASA's Space Chemistry Program.