1. Iron-60 and Sun formation COSMOCHEMISTRY iLLUSTRATED The 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)

2. Iron-60 and Sun formation COSMOCHEMISTRY iLLUSTRATED The 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 60 Fe (given by the 0.0 value of ε 60 Ni, the decay product of 60 Fe) In contrast, differentiated meteorites, which formed 1 My after initial solar system formation, have no evidence for 60 Fe (low ε 60 Ni)

3. Iron-60 and Sun formation COSMOCHEMISTRY iLLUSTRATED The Sun’s Crowded Delivery Room In spite of having had no 60 Fe, differentiated meteorites did contain 26 Al, as did most early solar system materials Martin Bizzarro and his colleagues suggest: – 26 Al was incorporated into the interstellar cloud that gave birth to the Sun when massive stars spewed strong stellar winds – 60 Fe 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 --