We have found that individual presolar silicon carbide (SiC) dust grains from supernovae show a positive correlation between ⁴⁹Ti and ²⁸Si excesses, which is attributed to the radioactive decay of the short-lived (t_½ = 330 days) ⁴⁹V to ⁴⁹Ti in the inner highly ²⁸Si-rich Si/S zone. The ⁴⁹V-⁴⁹Ti chronometer shows that these supernova SiC dust grains formed at least 2 years after their parent stars exploded. This result supports recent dust condensation calculations that predict a delayed formation of carbonaceous and SiC grains in supernovae. The astronomical observation of continuous buildup of dust in supernovae over several years can, therefore, be interpreted as a growing addition of C-rich dust to the dust reservoir in supernovae.

中文翻译：

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II型超新星中碳化硅的晚期形成。

我们已经发现，单个太阳前碳化硅（SiC）从超新星尘埃颗粒显示之间的正相关⁴⁹ Ti和^28个的Si过量，这归因于短命的放射性衰变（吨_½ =330天）⁴⁹ V至⁴⁹内部高²⁸ Si富Si / S区中的Ti 。在⁴⁹ V- ⁴⁹钛天文钟显示，这些超新星SiC尘埃粒子是在其母星爆炸至少两年后形成的。这一结果支持了最近的灰尘凝结计算，该计算预测了超新星中碳和SiC晶粒的延迟形成。因此，对超新星尘埃持续累积数年的天文观测可以解释为超新星尘埃储集层中富含C的粉尘的增加。