The elusive (60)Fe in the solar nebula

Frédéric Moynier (1) , Janne Blichert-Toft (2) , Kun Wang (1) , Gregory F. Herzog (3) , Francis Albarède (2)

1 McDonnell Center for Space Sciences
2 LGL-TPE - Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement
3 Department of Chemistry and Chemical Biology

No (60)Ni or (61)Ni anomalies have been detected in troilite inclusions from Muonionalusta, a 4565.3 +/- 0.1 Ma old IVA iron meteorite, to the level of the analytical precision of 10 ppm. Because Muonionalusta troilite is very old, has a high Fe/Ni ratio, and is free of (61)Ni anomalies, it is the ideal material in which to search for potential excesses of (60)Ni produced by the decay of (60)Fe (t(1/2) = 2.62 Ma). The (60)Ni/(58)Ni and Fe/Ni ratios (up to 1680) measured here imply an upper limit for the initial (60)Fe/(56)Fe for the Muonionalusta troilite of 3 x 10(-9). Assuming that (60)Fe was homogeneously distributed across the nebula, this result suggests that the solar system initial (60)Fe/(56)Fe ratio was less than 5 x 10(-9), which is lower than previously measured by at least a factor of 50

Mots clés: astrochemistry; minor planets; asteroids : general; nuclear reactions; nucleosynthesis; abundances; protoplanetary disks

Frédéric Moynier, Janne Blichert-Toft, Kun Wang, Gregory F. Herzog, Francis Albarède. The elusive (60)Fe in the solar nebula. The Astrophysical Journal, 2011, 741 (2), pp.71. ⟨10.1088/0004-637X/741/2/71⟩. ⟨insu-00674581⟩