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New findings on the birth of the solar system

29 July 2009

A team of international astrophysicists, including Dr Maria Lugaro from the Monash School of Mathematical Sciences, has discovered a new explanation for the early composition of our solar system.

They have found that radioactive nuclei found in the earliest meteorites, dating back billions of years, could have been delivered by a nearby dying giant star six times the mass of the sun.

Dr Lugaro said the findings could change current ideas on the origin of the solar system.

"We have known about the early presence of these radioactive nuclei in meteorites since the 1960s, but we do not know where they originated from," Dr Lugaro said.

"The presence of the radioactive nuclei has been previously linked to a nearby supernova explosion, but we are showing now that these nuclei are more compatible with an origin from the winds coming from a large dying star."

The conclusion was reached by combining stellar observations from telescopes with recently developed theoretical models of how stars evolve and which nuclear reaction occurs within their interiors.

"We need to know if the presence of radioactive nuclei in young planetary systems is a common or a special event in our galaxy because their presence affected the evolution of the first large rocks (the parent bodies of asteroids and meteorites) in the solar system. These are believed to be the source of much of earth's water, which is essential for life," Dr Lugaro said.

"We now need to investigate the probability that a dying giant star could have actually been nearby our then young solar system and polluted it with radioactive nuclei.

"This will inform us on the place where the solar system was born, on the probability that other young planetary system also are polluted with radioactive nuclei, and, eventually, on the probability of having water on terrestrial planets in other planetary systems."