ABSTRACT

The ¹⁴⁶Sm/¹⁴⁴Sm ratio at the time of solidification of four chondrites, Abee (E4), Modoc (L6), St. Séverin (LL6) and Allende (C3), were measured. The values obtained are 0.06 ± 0.25 (Abee), 0.03 ± 0.08 (Modoc), 0.06 ± 0.05 (St. Séverin) and 1.4 ± 2.0 (Allende), where quoted errors represent 2σ of York's method. Under the assumption of simultaneous formation of these chondrites, we can set an upper limit value of (¹⁴⁶Sm/¹⁴⁴Sm)₀ as 0.11. From this value it is concluded that “last spike” contribution was rather small for p-process nucleosynthesis.