Scientific Breakthrough: Astronomers Figure out Lithium Riddle in Exploding Stars

Using two telescopes in Chile, astronomers detected tiny amounts of the chemical element lithium in Nova Centauri – a star which exploded in 2013 — the brightest nova so far this century, the European Southern Observatory said this week. Intriguingly, younger stars have more lithium than older stars.

The finding is unique in the sense that it helps scientists solve a longstanding mystery in astrophysics about the quantity of the element that has been observed in stars.

Models of the Big Bang at the birth of the universe 13.8 billion years ago allow astronomers to calculate quite accurately how much lithium should be present.

“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,” said Massimo Della Valle, a coauthor of the study.

Scientists have always speculated that the latter part of the riddle could be better understood by novae expelling the element, “seeding” space with lithium and enriching the interstellar medium from which new stars are born.

However, no clear evidence has come to light of lithium in novae.The discovery of lithium being expelled at some 2 million kilometers (1.24 million miles) per hour in Nova Centauri could, when extrapolated to the billions of other novae that have exploded in the Milky Way’s history, explain the unexpectedly large amount of lithium in our galaxy, the ESO said.

The mismatch between the observed amount of lithium in older stars and the abundance estimated from the Big Bang, however, still remains an open problem, said Della Valle and team leader Luca Izzo.

The results of this breakthrough study were published in the Astrophysical Journal Letters.


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