Iron-60 and Sun formation COSMOCHEMISTRY iLLUSTRATED

The Sun’s Crowded Delivery RoomThe Sun’s Crowded Delivery Room

• Telescopic observations suggest that stars, even isolated ones like the Sun, form in clusters

• Meteorite studies can test this idea and give additional information about events leading to formation of the Solar System

Moon

Cluster of new stars in the constellation of Vela (Courtesy of European Southern Observatory)

Iron-60 and Sun formation COSMOCHEMISTRY iLLUSTRATED

The Sun’s Crowded Delivery RoomThe Sun’s Crowded Delivery Room

• Precise analyses by Martin Bizzarro and his colleagues show that Earth, Mars, and chondritic meteorites contain evidence for the presence of 60Fe (given by the 0.0 value of ε60Ni, the decay product of 60Fe)

• In contrast, differentiated meteorites, which formed 1 My after initial solar system formation, have no evidence for 60Fe (low ε60Ni)

Iron-60 and Sun formation COSMOCHEMISTRY iLLUSTRATED

The Sun’s Crowded Delivery RoomThe Sun’s Crowded Delivery Room

• In spite of having had no 60Fe, differentiated meteorites did contain 26Al, as did most early solar system materials

• Martin Bizzarro and his colleagues suggest:– 26Al was incorporated into the

interstellar cloud that gave birth to the Sun when massive stars spewed strong stellar winds

– 60Fe was added a million years later when a massive star exploded

Stellar winds blowing from a massive Wolf-Rayet star (brightest star near center) in NGC 2359 Nebula. Courtesy of P. Berlind & P. Challis, Harvard-Smithsonian Center for Astrophysics.

Wolf-Rayet star --