One of the most important building stones of our physical Universe, and one of the largest, missing pieces in the jigsaw that the Big Bang theory presents, is lithium. And up until recently, scientists have scratched their heads trying to get evidence of enough lithium presence out there, to explain the existing but not completely consistent levels of it inside stars.
At ESO, a team of scientists led by Luca Izzo, from the Sapienza University of Rome and also ICRAnet, in Pescara, Italy, made the discovery as they used the FEROS instrument and the PUCHEROS spectrograph, placed on the ESO 0.5-metre telescope at the Observatory of the Pontifical Universidad Catolica de Chile, located in Santa Martina not far from Santiago. They used the instruments to study Nova Centauri 2013, a star that exploded in December 2013 in the southern skies and was even visible to the eye. It holds the record for being the brightest nova of this century, and now, it’s also contributed to solve the lithium mystery.
In the journal Astrophysical Journal Letters, the team talked about their discovery: “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.”
Now the scientists have a way to calculate rather than wonder about why such a large number of young stars apparently have some times ten times more lithium than they were supposed to have, and why older stars have less of it than anticipated. Star explosions eject material that some day begins gathering to form new stars, so the matter of understanding where lithium fits in has been a great challenge.
The Nova Centauri 2013 resulted in data showing how lithium is expelled as fast as two million kilometers per hour, and this type of ejection has never been recorded before. By combining the many billions of nova outbursts throughout time in the Milky Way, even these small amounts of lithium, which is even less than a billionth of the Sun mass, will do to give a reliable explanation to the already noted and quite large lithium amounts surrounding us in the galaxy.