Triggered Star Formation inside the Shell of a Wolf-Rayet Bubble as the Origin of the Solar System.

Abstract

A constraint on Solar System formation is the high ²⁶Al/²⁷Al abundance ratio, 17 times higher than the average Galactic ratio, while the ⁶⁰Fe/⁵⁶Fe value was lower than the Galactic value. This challenges the assumption that a nearby supernova was responsible for the injection of these short-lived radionuclides into the early Solar System. We suggest that the Solar System was formed by triggered star formation at the edge of a Wolf-Rayet (W-R) bubble. We discuss the details of various processes within the model using numerical simulations, and analytic and semi-analytic calculations, and conclude that it is a viable model that can explain the initial abundances of ²⁶Al and ⁶⁰Fe. We estimate that 1%-16% of all Sun-like stars could have formed in such a setting.