Akademska digitalna zbirka SLovenije - logo
E-viri
Recenzirano Odprti dostop
  • Triggered Star Formation in...
    Dwarkadas, Vikram V.; Dauphas, Nicolas; Meyer, Bradley; Boyajian, Peter; Bojazi, Michael

    The Astrophysical journal, 12/2017, Letnik: 851, Številka: 2
    Journal Article

    A critical constraint on solar system formation is the high /27Al abundance ratio of at the time of formation, which was about 17 times higher than the average Galactic ratio, while the 60Fe/56Fe value was about , lower than the Galactic value. This challenges the assumption that a nearby supernova (SN) was responsible for the injection of these short-lived radionuclides into the early solar system. We show that this conundrum can be resolved if the solar system was formed by a triggered star formation at the edge of a Wolf-Rayet (W-R) bubble. 26Al is produced during the evolution of the massive star, released in the wind during the W-R phase, and condenses into dust grains that are seen around W-R stars. The dust grains survive passage through the reverse shock and the low-density shocked wind, reach the dense shell swept-up by the bubble, detach from the decelerated wind, and are injected into the shell. Some portions of this shell subsequently collapse to form the dense cores that give rise to solar-type systems. The subsequent aspherical SN does not inject appreciable amounts of into the proto-solar system, thus accounting for the observed low abundance of . We discuss the details of various processes within the model and conclude that it is a viable model that can explain the initial abundances of and . We estimate that 1%-16% of all Sun-like stars could have formed in such a setting of triggered star formation in the shell of a W-R bubble.