New CrH Opacities for the Study of L and Brown Dwarf Atmospheres
New CrH Opacities for the Study of L and Brown Dwarf Atmospheres
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用于研究 L 和褐矮星大气的新 CrH 不透明度
DOI：
10.1086/342242
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
J. Milsom
中科院分区：
文献类型：
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作者：
A. Burrows;R. S. Ram;P. F. Bernath;P. F. Bernath;C. Sharp;J. Milsom
在本文中，我们计算了 CrH 分子 A 6Σ+-X 6Σ+ 跃迁 12 个能带的新谱线列表和不透明度。 CrH 分子在新的 L 矮星光谱类别（其中许多是褐矮星）以及太阳黑子中被识别出来，在低温大气的诊断中发挥着重要作用。作为这些不透明度的首次尝试性应用，我们在大气代码中采用了新的理论 CrH 数据，以获得 L5 矮星 2MASSI J1507038-151648 表皮的 CrH/H2 数比，约为 (2-4) × 10-9，与化学平衡预期大致一致。由于在之前的汇编中，振荡强度偏离了一个数量级以上，因此这一协议代表了适度的进步。然而，为了适应 L 矮星光谱类别中的 CrH 丰度，需要将硅酸盐云纳入模型中。鉴于这一主题仍处于发展的初级阶段，人们应该将 L 矮星范围内的任何光谱模型视为仅仅是尝试性的。尽管如此，L 矮星建模必要的第一步是可靠的 CrH 不透明度算法，这就是我们在这里试图提供的。
In this paper, we calculate new line lists and opacities for the 12 bands of the A 6Σ+-X 6Σ+ transitions of the CrH molecule. Identified in objects of the new L dwarf spectroscopic class (many of which are brown dwarfs), as well as in sunspots, the CrH molecule plays an important role in the diagnosis of low-temperature atmospheres. As a tentative first application of these opacities, we employ our new theoretical CrH data in an atmospheres code to obtain a CrH/H2 number ratio for the skin of the L5 dwarf 2MASSI J1507038-151648 of ~(2-4) × 10-9, in rough agreement with chemical equilibrium expectations. Since in previous compilations the oscillator strength was off by more than an order of magnitude, this agreement represents a modest advance. However, in order to fit the CrH abundance in the L dwarf spectral class, silicate clouds need to be incorporated into the model. Given that this subject is still in a primitive stage of development, one should view any spectral model in the L dwarf range as merely tentative. Nevertheless, a necessary first step in L dwarf modeling is a reliable CrH opacity algorithm, and this is what we have here attempted to provide.