Instituto de Astrofisíca de Canarias, Via Láctea s/n, E-38200 La Laguna, Spain.
Nature. 2009 Nov 12;462(7270):189-91. doi: 10.1038/nature08483.
The surface abundance of lithium on the Sun is 140 times less than the protosolar value, yet the temperature at the base of the surface convective zone is not hot enough to burn-and hence deplete-Li (refs 2, 3). A large range of Li abundances is observed in solar-type stars of the same age, mass and metallicity as the Sun, but such a range is theoretically difficult to understand. An earlier suggestion that Li is more depleted in stars with planets was weakened by the lack of a proper comparison sample of stars without detected planets. Here we report Li abundances for an unbiased sample of solar-analogue stars with and without detected planets. We find that the planet-bearing stars have less than one per cent of the primordial Li abundance, while about 50 per cent of the solar analogues without detected planets have on average ten times more Li. The presence of planets may increase the amount of mixing and deepen the convective zone to such an extent that the Li can be burned.
太阳表面的锂丰度比原始太阳值低 140 倍，但表面对流区底部的温度不够高，不足以燃烧和消耗锂（参考文献 2、3）。在与太阳具有相同年龄、质量和金属丰度的太阳型恒星中，观测到了大范围的锂丰度，但这种范围在理论上很难理解。早些时候有人提出，在有行星的恒星中，锂的消耗程度更大，但由于缺乏适当的无探测行星恒星的比较样本，这一说法被削弱了。在这里，我们报告了具有和不具有探测到的行星的太阳相似恒星的无偏样本的锂丰度。我们发现，有行星的恒星的原始锂丰度不到百分之一，而大约 50%的没有探测到行星的太阳相似恒星的平均锂丰度则高出十倍。行星的存在可能会增加混合程度，并加深对流区，以至于锂可以被燃烧。
