Star collisions spray heavy elements in small galaxies

Star collisions spray heavy elements in small galaxies

A dwarf galaxy in the constellation Sculptor is one of the tiniest galaxies. Scientists have found that most of the heavy elements of these galaxies are formed by the merging of neutron stars

Researchers at Caltech found that the fusion of neutron stars leads to the formation of most of the heavy elements in small dwarf galaxies. Elements like silver and gold are considered key to creating planets and life itself.

For more than a decade, scientists have tried to understand the origin of most of the heaviest elements of the periodic table, including 95% of all gold on Earth. Now it is known that they are created when the nuclei of atoms in stars capture neutrons. This is a fast process, so it is marked as “r-process”.

There are two favorable places for such events. The first is a rare type of stellar explosion (supernova) when large magnetic fields are created. The second is the fusion of two neutron stars. In August 2017, LIGO captured one such collision. To study the issue of creating heavy elements in galaxies, scientists examined several nearby dwarf types using the Keck Observatory (Hawaii). The Milky Way is considered a medium-sized galaxy, while dwarf ones are endowed with stellar massiveness of about 100,000 times smaller. Researchers studied when the heaviest elements appeared.

The analysis showed that the dominant sources of the r-process in dwarf galaxies occur on a relatively long time frame. That is, they appeared later in the history of the universe. It is the delay that brings the option with the collision of neutron stars to the fore.

Researchers are often guided precisely by dwarf galaxies. This species was isolated when their stars appeared, making it possible to track the accumulation of the r-process over time.

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