Calculations of the far-wing line profiles of sodium and potassium in the atmospheres of substellar-mass objects
Calculations of the far-wing line profiles of sodium and potassium in the atmospheres of substellar-mass objects
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DOI：
10.1086/345412
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发表时间：
2003-02-01
影响因子：
4.9
通讯作者：
Volobuyev, M
中科院分区：
文献类型：
--
作者：
Burrows, A;Volobuyev, M
在冷的褐矮星和热的巨行星大气中达到的低温下，不那么难熔的中性碱金属在光谱形成中扮演了一个不同寻常的重要角色。特别是，翅膀的Na-D（5890埃）和KI（7700埃）的共振线来定义的连续和占主导地位的光谱的T矮星从0.4到1.0妈妈。在标准恒星大气中，原子光谱线的翼的强度和形状很少需要超过25埃的线中心，而在褐矮星中，Na和K共振线的远翼达到数千埃的失谐是重要的。利用标准量子化学程序和统一的Franck-Condon准静态极限谱线模型，计算了富氢和氦大气中Na和K共振谱线的相互作用势和翼线形状.我们的理论有自然的吸收轮廓截止，没有自由参数，并很容易适应恒星，棕矮星，和行星的有效温度低于2000 K的光谱合成计算。
At the low temperatures achieved in cool brown dwarf and hot giant planet atmospheres, the less refractory neutral alkali metals assume an uncharacteristically prominent role in spectrum formation. In particular, the wings of the Na-D (5890 Angstrom) and K I (7700 Angstrom) resonance lines come to de ne the continuum and dominate the spectrum of T dwarfs from 0.4 to 1.0 mum. Whereas in standard stellar atmospheres the strengths and shapes of the wings of atomic spectral lines are rarely needed beyond 25 Angstrom from a line center, in brown dwarfs the far wings of the Na and K resonance lines out to thousands of angstroms detunings are important. Using standard quantum chemical codes and the unified Franck-Condon model for line profiles in the quasi-static limit, we calculate the interaction potentials and the wing line shapes for the dominant Na and K resonance lines in H-2- and helium-rich atmospheres. Our theory has natural absorption profile cutoffs, has no free parameters, and is readily adapted to spectral synthesis calculations for stars, brown dwarfs, and planets with effective temperatures below 2000 K.