This Record-Breaking 'Gold Standard' Star Is Unlike Any We've Seen Before - ScienceAlert

Since these elements can only form in extremely energetic events such as supernovae or neutron star mergers, via a mechanism called the rapid neutron-capture process, this star's composition could be a means to learn more about how heavy elements form.

In the early Universe, hydrogen and helium – still the two most abundant elements in the cosmos – constituted pretty much all matter.

In the nuclear fusion furnaces of their cores, these stars forged hydrogen into helium; then helium into carbon; and so on, fusing heavier and heavier elements as they run out of lighter ones until iron is produced.

To create elements heavier than iron, the rapid neutron-capture process, or r-process, is required.

It's also what is known as a "metal-poor" star, low in heavier elements… but extremely enriched in elements that can only be produced by the r-process.

Therefore, r-process elements had somehow been distributed throughout the molecular cloud of hydrogen and helium from which HD 222925 formed, around 8.2 billion years ago?

Although we don't know whether the r-processes that produced these elements took place in a neutron star collision or a violent supernova, the level of detail that we now have means the star can be used as a sort of blueprint for understanding the output of the r-process.