It is generally accepted that such elements are synthesized only in extreme processes of neutron star mergers
Five new isotopes have been synthesized as part of research at the Facility for Rare Isotopes (FRIB) at Michigan State University: thulium-182, thulium-183, ytterbium-186, ytterbium-187 and lutetium-190. This is the first time that scientists have been able to obtain these isotopes on Earth; they have not been found on our planet before.
Mergers of super-dense neutron stars are considered one of the possible scenarios for the formation of heavy elements such as gold and silver. This research brings scientists closer to understanding the processes that occur during such fusions and the formation of heavy elements.
Stars can be considered as nuclear furnaces in which the synthesis of elements starting from hydrogen and ending with iron occurs. However, to create elements heavier than iron, a special condition is required — collision of neutron stars.
At the end of the life cycle of massive stars, their iron cores remain, which cannot synthesize heavy elements. The energy that kept these stars from collapsing due to their own gravitational influence is running out. This leads to nuclear collapse and supernova explosions. However, this collapse can be stopped when electrons and protons become a sea of neutrons, which are prevented from merging by an aspect of quantum physics called “degeneracy.” This degeneracy pressure can be overcome if the core of the ?? star has sufficient mass, resulting in collapse and «birth» black hole. But sometimes the initial mass is not enough and the stars are «reborn» into neutron stars.
Moreover, it is not the end of nuclear fusion if the neutron star exists in a binary system with another massive star that also eventually «regenerated» into a neutron star.
These super-dense stars, with masses one to two times greater than the Sun, orbit each other in narrow orbits and emit gravitational waves. Gravitational waves carry away angular momentum from the system, causing the neutron stars to move closer together and emit gravitational waves with greater intensity. This continues until they eventually merge with each other.
Given the extreme nature of the process, collisions of neutron stars in such binary systems create an extremely aggressive environment. For example, this event releases a substance rich in neutrons. This substance is believed to be important for the synthesis of gold and other heavy elements. Free neutrons can be captured by other atomic nuclei. These atomic nuclei then become heavier, giving rise to superheavy unstable isotopes. These unstable isotopes eventually decay into stable elements such as gold, which are lighter than superheavy elements but heavier than iron.
If scientists could recreate the superheavy elements involved in this process, they would be able to better understand the process of creating gold and other heavy elements. Synthesis of five new isotopes — thulium-182, thulium-183, ytterbium-186, ytterbium-187 and lutetium-190 — It just allows scientists to recreate the conditions in which heavy elements are formed. They are created by firing platinum ions at a target in a FRIB. Although it is likely that these isotopes are not present in the debris of neutron stars, their creation on Earth is a step towards the creation of transition superheavy elements that can later decay into stable elements, including gold.