SDSS J141624.08+134826.7: BLUE L DWARFS AND NON-EQUILIBRIUM CHEMISTRY
SDSS J141624.08+134826.7: BLUE L DWARFS AND NON-EQUILIBRIUM CHEMISTRY
复制标题
SDSS J141624.08 134826.7：蓝 L 矮星和非平衡化学
DOI：
10.1088/0004-6256/140/5/1428
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
M. Marley
中科院分区：
文献类型：
--
作者：
M. Cushing;M. Cushing;D. Saumon;M. Marley
我们对最近发现的蓝L矮星SDSS J141624.08+134826.7进行了分析。我们通过在NASA IRTF上使用SpeX获得低分辨率L波段光谱，将其公布光谱的光谱覆盖范围扩展到104 μm。该光谱在3.3 μm处显示出一个初步的弱CH 4吸收特征，但在其他地方没有特征。我们通过比较SDSS J141624.08+134826.7的0.7-4.0 μm光谱与Marley和Saumon的大气模型（包括凝结云形成和由于垂直混合引起的非平衡化学的影响）来推导其大气参数，发现最佳拟合模型为Teff = 1700 K，log g = 5.5（cm s−2），fsed = 4，Kzz = 104 cm 2 s-1。导出的有效温度比以前估计的要低得多，但我们证实了Bowler等人的建议，即SDSS J141624.08+134826.7的特殊光谱主要是薄凝结云的结果。此外，在SDSS J141624.08+134826.7的大气中，没有化学平衡模式预测的3.3 μm深的CH 4吸收带，这也为大气垂直混合提供了强有力的证据。最后，这一结果表明，蓝L矮星的观测是一个有吸引力的方式来定量估计混合的活力在大气中的L矮星，因为这种混合的显着影响的强度的3.3 μm的CH 4带的出射光谱的薄凝聚云的L矮星。
We present an analysis of the recently discovered blue L dwarf SDSS J141624.08+134826.7. We extend the spectral coverage of its published spectrum to ∼4 μm by obtaining a low-resolution L-band spectrum with SpeX on the NASA IRTF. The spectrum exhibits a tentative weak CH4 absorption feature at 3.3 μm but is otherwise featureless. We derive the atmospheric parameters of SDSS J141624.08+134826.7 by comparing its 0.7–4.0 μm spectrum to the atmospheric models of Marley and Saumon which include the effects of both condensate cloud formation and non-equilibrium chemistry due to vertical mixing and find the best-fitting model has Teff = 1700 K, log g = 5.5 (cm s−2), fsed = 4, and Kzz = 104 cm2 s−1. The derived effective temperature is significantly cooler than previously estimated but we confirm the suggestion by Bowler et al. that the peculiar spectrum of SDSS J141624.08+134826.7 is primarily a result of thin condensate clouds. In addition, we find strong evidence of vertical mixing in the atmosphere of SDSS J141624.08+134826.7 based on the absence of the deep 3.3 μm CH4 absorption band predicted by models computed in chemical equilibrium. Finally, this result suggests that observations of blue L dwarfs are an appealing way to quantitatively estimate the vigor of mixing in the atmospheres of L dwarfs because of the dramatic impact such mixing has on the strength of the 3.3 μm CH4 band in the emergent spectra of L dwarfs with thin condensate clouds.