Understanding the cosmic origins of heavy elements

Analyzing light from a kilonova, a birthplace of heavy elements.

Artist’s impression of a kilonova caused by a neutron star merger. In the material released by the merger, various heavy elements are formed, which then absorb and emit light. New atomic data calculations help to clarify kilonovae. Credit: National Astronomical Observatory of Japan
Artist’s impression of a kilonova caused by a neutron star merger. In the material released by the merger, various heavy elements are formed, which then absorb and emit light. New atomic data calculations help to clarify kilonovae. Credit: National Astronomical Observatory of Japan

Atoms and ions can absorb and emit certain colors of light. By analyzing the detailed colors of inaccessible objects, like high-temperature plasmas in a fusion chamber or distant stars, scientists can identify their elemental abundances. In a new study, a team of experts in atomic physics, nuclear fusion, and astronomy has computed high-accuracy atomic data for analyzing light from a kilonova, an origin of heavy elements.

The outcomes suggest that their new data set could predict kilonovae brightness with much better precision. According to scientists, this could help them better understand the cosmic origins of heavy elements.

To better identify elemental abundances of heavy metals, scientists require atomic data about the wavelengths of light absorbed and emitted by each element. Yet, there is no far-reaching, precise atomic data for the heavy elements which are believed to be formed in kilonovae.

For the study, scientists used techniques from nuclear fusion research to gauge a huge number of very exact atomic data for neodymium ions. Neodymium is one of the vital elements for kilonovae radiation and is very much concentrated by experiments and simulations.

Kato said, “The Atomic structure of neodymium is more complicated than those of lighter elements, such as iron, calculated for nuclear fusion science. We needed to extend and optimize our calculation methods for such an element with so complicated structure.”

At the point when two neutron stars collide and break apart, spewing waves of unstable nuclear material into space. This material rapidly decays causing radioactive afterglow known as a kilonova.

According to scientists, the nuclear reactions in neutron star mergers could be one of the essential hotspots for the heavy elements, including valuable metals, for example, gold and platinum, and uncommon earth metals, for example, neodymium.

The computed data for the neodymium is far accurate than any other calculations have done, reported scientists.

An astronomer in the research group, Masaomi Tanaka, Associate Professor at Tohoku University simulated the light of a kilonova with a supercomputer at the National Astronomical Observatory of Japan (NAOJ) using new atomic data, and for the first time in the world, he could evaluate the influence of the database precision on the predicted brightness of a kilonova.

He found that the answer varied by about 20% at most, which is sufficiently accurate to give astronomers confidence in their interpretation of kilonova observations. By calculating atomic data for other metals with this method developed in fusion science, the detail abundances of cosmic heavy elements formed by kilonovae will come to light.

The team was lead by Daiji Kato, Associate Professor at the National Institute for Fusion Science (NIFS) in Japan, and Gediminas Gaigalas, Professor at Vilnius University in Lithuania.

The study is published in the journal the Astrophysical Journal Supplement Series.