Skip to navigation | Skip to content

How death gave birth to our solar system

Supernova 7112011W49b_475x356

New computer simulations indicate the death of a star in a supernova may have triggered the birth of our Sun and solar system (Source: NASA/GSFC/Chandra X-Ray Observatory)

Solar system birth Our solar system was born thanks to the death of a nearby star in a spectacular supernova event, say researchers.

The findings are based on new computer simulations developed by Dr Matthias Gritschneder, from Beijing's Peking University, and colleagues, and published on the pre-press website

Gritschneder and colleagues found shock waves generated by a supernova could have caused the collapse of a molecular gas and dust cloud, eventually leading to the formation of the Sun and planets.

The model also explains unusual isotope readings in some of the oldest bodies of the solar system.

Stars and solar systems are created in the collapse of molecular gas and dust clouds.

Scientists say this is what happened to our solar system about 4.6 billion years ago, but until now they didn't know what triggered that collapse.

Clues have been found in the ratio of aluminium isotopes found in meteorites formed during the molecular cloud collapse.

Ancient meteorites

The isotope aluminium-26 usually has a half life of 700,000 years, eventually changing in to magnesium-26.

However the ratio of aluminium isotopes in ancient carbonaceous chondrite meteorites, called CV-chondrites, is unusually high.

CV-chondrites are thought to have formed directly out of the collapse of the molecular cloud that gave birth to our solar system.

The unusual isotope measurements suggest fresh aluminium-26 was being fed into this molecular cloud as it collapsed, either by stellar winds from a local star, or by the blast of a nearby supernova explosion, caused by the death of a star.

Gritschneder and colleagues say their model shows a supernova event 15 light years away was the most likely trigger.

"The blast's shock wave and hot gases travelled through space eventually colliding with a molecular cloud of cold gas and dust, causing it to quickly collapse, forming the Sun and solar system," says Gritschneder.

"It also provides the right ratios of aluminium isotopes to explain the levels found in CV meteorites."

"The CV-chondrites probably formed when the temperature of gas cloud dropped below about 1800°C," says Gritschneder.

"The model also shows how this would have occurred over a period of just 20,000 years, matching isotope measurements which act like time stamps marking the formation of these meteorites to within 20,000 years of each other."

Answers all the questions

Australian Astronomical Observatory astronomer Dr Stuart Ryder says the computer simulation neatly shows how a supernova blast wave could provide both the trigger for the collapse of a molecular cloud forming our Sun and solar system, and also seed the cloud with right amount of radioactive isotopes measured in the meteorites.

"The model also helps resolve how quickly the solar system formed," says Ryder.

"The argument has been that the meteorites must have all been formed in about the same place and at about the same time, and this explains how and why it happened."

"It also highlights the significance of supernovae marking the death of one star and at the same time triggering the birth of another," says Ryder.

Tags: planets-and-asteroids, physics, stars