论文标题
用氢对钛丰度确定的碰撞影响凉星
Influence of Collisions with Hydrogen on Titanium Abundance Determinations in Cool Stars
论文作者
论文摘要
我们用更新的模型原子进行了非本地热力学平衡（非L-LTE）计算，其中包括与氢原子无弹性碰撞的量子机械速率系数。我们已经首次计算了钛原子和离子与氢原子的非弹性碰撞和电荷交换过程的界限过渡的速率系数：ti i + h <-> h <-> ti ii + h-和ti II + h <-> h <-> ti iii + h-。这些数据对非LTE丰度确定的影响已经测试了太阳和四个金属贫困星。对于Ti I和Ti II，与LTE相比，衍生速率系数的应用导致与LTE的偏离和钛丰度的增加增加，与速率系数的近似公式相比获得。在金属贫困的恒星中，我们未能从两个电离阶段的线上实现一致的非LTE丰度。在与氢原子的碰撞中，在与经典模型大气的非LTE计算中，无法通过提高非弹性过程的速率来解决文献中的文献差异和金属贫困星的非LTE丰度和Ti II线的已知差异。
We performed the non-local thermodynamic equilibrium (non-LTE) calculations for Ti I-II with the updated model atom that includes quantum-mechanical rate coefficients for inelastic collisions with hydrogen atoms. We have calculated for the first time the rate coefficients for bound-bound transitions in inelastic collisions of titanium atoms and ions with hydrogen atoms and for the charge-exchange processes: Ti I + H <-> Ti II + H- and Ti II + H <-> Ti III + H-. The influence of these data on non-LTE abundance determinations has been tested for the Sun and four metal-poor stars. For Ti I and Ti II, the application of the derived rate coefficients has led to an increase in the departures from LTE and an increase in the titanium abundance compared to that, obtained with approximate formulas for the rate coefficients. In metal-poor stars, we have failed to achieve consistent non-LTE abundances from lines of two ionization stages. The known in the literature discrepancy in the non-LTE abundances from Ti I and Ti II lines in metal-poor stars cannot be solved by improvement of the rates of inelastic processes in collisions with hydrogen atoms in non-LTE calculations with classical model atmospheres.
