The discovery of lithium in the debris of an exploding star has allowed astronomers to unravel one of the outstanding mysteries of the Universe. This discovery could explain how young stars are able to contain higher concentrations of the element than should be present in the stellar bodies.
Nova Centauri 2013 (also called V1369 Centauri) erupted in the nearly Centauri star system two years ago, becoming visible to the naked eye. These events take place in binary systems, where one partner loses material to its companion. When this deposit of gas and dust reaches a certain critical threshold, the gas erupts into a violent explosion.
Astronomers have long known that these events result in elements being spread from the erupting star system to surrounding space. There, the material enriches the next generation of stars. However, astronomers had never before been able to detect lithium emanating from the cosmic explosions.
When matter first formed following the formation of the universe, a small amount of lithium was created. However, astronomers have noted that younger stars contain higher concentrations of the metallic element that older stellar bodies. This suggests that a mechanism had to be producing the element. Astronomers first recorded the element being produced in a nova during the 2013 event.
"It is a very important step forward. If we imagine the history of the chemical evolution of the Milky Way as a big jigsaw, then lithium from novae was one of the most important and puzzling missing pieces. In addition, any model of the Big Bang can be questioned until the lithium conundrum is understood," Massimo Della Valle from INAF-Osservatorio Astronomico di Capodimonte in Naples, Italy, said.
Most heavy elements are produced during supernovae, as massive stars explode in their death throes. However, these events were believed to be too rare to produce the vast amounts of lithium seen in the modern universe. Starting in the 1970s, astrophysicists began to explore the idea that the smaller but far more common novae could provide the material needed to spice surrounding stars with the element.
The quantity of lithium produced in the nova in the Centauri system was relatively small. However, researchers believe that enough of these events may occur throughout the universe to explain the discrepancy seen in lithium concentrations in younger and older stars.
"It is very exciting to find something that was predicted before I was born and then first observed on my birthday in 2013!" said Luca Izzo of Sapienza University of Rome.
Analysis of lithium concentrations in the nearby 2013 nova was published in Astrophysical Journal Letters.
