论文标题
在铁陨石中，相对较高的初始$^{60} $ fe的可能含义是非碳质的 - 碳质陨石二分法和太阳星云形成
Possible Implications of Relatively High Levels of Initial $^{60}$Fe in Iron Meteorites for the Non-Carbonaceous -- Carbonaceous Meteorite Dichotomy and Solar Nebula Formation
论文作者
论文摘要
库克等人。 （2021）发现铁陨石的最初丰度比稳定的同位素$^{60} $ fe对稳定的同位素$^{56} $^{60} $^{60} $^{60} $ fe/$^{56} $^{56} $ fe $ \ $ \ sim $ $ \ sim $ $（6.4 \ pm 2.0 \ pm 2.0 \ pm 2.0 \ pm 2.0）这似乎需要从II型超新星（SN II）中注入活$^{60} $ Fe进入前层分子云核，因为观察到的比率超过十倍以上的倍数超过预期在星际星际介质（ISM）中预期的倍数。超新星触发和注射方案为升高的初始$^{60} $ fe水平提供了现成的解释，此外，还提供了一种物理机制来解释非碳质 - 碳酸盐（NC-CC）陨石的二分法。 NC-CC方案假设太阳星云富集在超新星衍生的核素中，然后积聚的材料在超新星衍生的核素中耗尽。虽然NC-CC二分法是指稳定的核素，而不是$^{60} $ fe之类的短寿命同位素，但SN II触发假设为Solar Nebula积聚的原本无法解释的核素变化提供了解释。 SN II冲击触发的崩溃的三维流体动力学模型表明，在触发前极云核的崩溃后，冲击锋将当地的ISM扫除，同时将所得的Protostar/disk加速至几km/s的速度，足以使$ \ sim $ \ sim a verion tree complient a Myr seecount a Morection tree comply a Morection tree comply of tree comply of a verion deled of soilder of soild of soild of a griond of a griont of soild of a griond of sovil of sovil of a的杂物。超新星衍生核素的清单。
Cook et al. (2021) found that iron meteorites have an initial abundance ratio of the short-lived isotope $^{60}$Fe to the stable isotope $^{56}$Fe of $^{60}$Fe/$^{56}$Fe $\sim$ $(6.4 \pm 2.0) \times 10^{-7}$. This appears to require the injection of live $^{60}$Fe from a Type II supernova (SN II) into the presolar molecular cloud core, as the observed ratio is over a factor of ten times higher than would be expected to be found in the ambient interstellar medium (ISM) as a result of galactic chemical evolution. The supernova triggering and injection scenario offers a ready explanation for an elevated initial $^{60}$Fe level, and in addition provides a physical mechanism for explaining the non-carbonaceous -- carbonaceous (NC-CC) dichotomy of meteorites. The NC-CC scenario hypothesizes the solar nebula first accreted material that was enriched in supernova-derived nuclides, and then later accreted material depleted in supernova-derived nuclides. While the NC-CC dichotomy refers to stable nuclides, not short-lived isotopes like $^{60}$Fe, the SN II triggering hypothesis provides an explanation for the otherwise unexplained change in nuclides being accreted by the solar nebula. Three dimensional hydrodynamical models of SN II shock-triggered collapse show that after triggering collapse of the presolar cloud core, the shock front sweeps away the local ISM while accelerating the resulting protostar/disk to a speed of several km/s, sufficient for the protostar/disk system to encounter within $\sim$ 1 Myr the more distant regions of a giant molecular cloud complex that might be expected to have a depleted inventory of supernova-derived nuclides.
