,
(July 29, 2015) The
chemical element lithium has been found for the first time in material ejected
by a nova. Observations of Nova Centauri 2013 made using telescopes at ESO’s La
Silla Observatory, and near Santiago in Chile, help to explain the mystery of
why many young stars seem to have more of this chemical element than expected.
This new finding fills in a long-missing piece in the puzzle representing our
galaxy’s chemical evolution, and is a big step forward for astronomers trying
to understand the amounts of different chemical elements in stars in the Milky
Way.
The light chemical element lithium is one of the few
elements that is predicted to have been created by the Big Bang, 13.8 billion
years ago. But understanding the amounts of lithium observed in stars around us
today in the Universe has given astronomers headaches. Older stars have less
lithium than expected [1], and some younger ones up to ten times more [2].
Since the 1970s, astronomers have speculated that much of
the extra lithium found in young stars may have come from novae — stellar
explosions that expel material into the space between the stars, where it
contributes to the material that builds the next stellar generation. But
careful study of several novae has yielded no clear result up to now.
A team led by Luca Izzo (Sapienza University of Rome, and
ICRANet, Pescara, Italy) has now used the FEROS instrument on the MPG/ESO
2.2-metre telescope at the La Silla Observatory, as well the PUCHEROS
spectrograph on the ESO 0.5-metre telescope at the Observatory of the
Pontificia Universidad Catolica de Chile in Santa Martina near Santiago, to
study the nova Nova Centauri 2013 (V1369 Centauri). This star exploded in the
southern skies close to the bright star Beta Centauri in December 2013 and was
the brightest nova so far this century — easily visible to the naked eye [3].