论文标题
A 1.46-2.48 $ m $ m m $ m光谱地图t6矮人（1060 K）带有Igrins的氛围：h $ _2 $ s and H $ _2 $的首次检测，以及h $ _2 $ o，ch $ _4 $的验证
A 1.46-2.48 $μ$m Spectroscopic Atlas of a T6 Dwarf (1060 K) Atmosphere with IGRINS: First Detections of H$_2$S and H$_2$, and Verification of H$_2$O, CH$_4$, and NH$_3$ Line Lists
论文作者
论文摘要
我们介绍了双子座南/Igrins的观察，即1060 K T6矮人2MASS J08173001 $ - $ 6155158，具有前所未有的分辨率（$ \equivλ/δλ= 45 \，000 $，000 $）和信号到薪水比率（SNR> 200）的后期（SNR> 200）。我们使用此基准观察来测试用最新大气模型的分子线列表的可靠性。我们确定应使用哪些光谱区域来估计冷棕色矮人的参数，并扩展为系外行星。我们提供了一个详细的光谱图集，并在$ H $和$ k $的近红外带中进行了分子识别。我们发现水（h $ _2 $ o）线列表总体上是可靠的。我们发现旧甲烷（CH $ _4 $）行列表中最差异，并且最新的CH $ _4 $ lines列表正确了许多此类问题。我们将单个氨（NH $ _3 $）线，硫化氢（H $ _2 $ s）的特征以1.5900 $ $ m和2.1218 $ $ m的分子氢（h $ _2 $）的特征确定。这些是H $ _2 $ S和H $ _2 $吸收功能的第一个明确检测。通过h $ _2 $检测，我们对此T6矮人的大气灰尘浓度放置了上限：至少比星际值小500倍，这意味着大气有效地没有尘埃。我们还确定了模型光谱中未出现的几个功能。我们对线条列表的评估对于大气模型在高分散，低sNR，高背景光谱中的应用很有价值，例如围绕恒星的系外行星。我们在T6矮人的CH $ _4 $吸收信号的检测中证明了显着的增强，并具有最新的生产线列表。
We present Gemini South/IGRINS observations of the 1060 K T6 dwarf 2MASS J08173001$-$6155158 with unprecedented resolution ($R\equivλ/Δλ=45\,000$) and signal-to-noise ratio (SNR > 200) for a late-type T dwarf. We use this benchmark observation to test the reliability of molecular line lists used up-to-date atmospheric models. We determine which spectroscopic regions should be used to estimate the parameters of cold brown dwarfs and, by extension, exoplanets. We present a detailed spectroscopic atlas with molecular identifications across the $H$ and $K$ bands of the near-infrared. We find that water (H$_2$O) line lists are overall reliable. We find the most discrepancies amongst older methane (CH$_4$) line lists, and that the most up-to-date CH$_4$ line lists correct many of these issues. We identify individual ammonia (NH$_3$) lines, a hydrogen sulfide (H$_2$S) feature at 1.5900 $μ$m, and a molecular hydrogen (H$_2$) feature at 2.1218 $μ$m. These are the first unambiguous detections of H$_2$S and H$_2$ absorption features in an extra-solar atmosphere. With the H$_2$ detection, we place an upper limit on the atmospheric dust concentration of this T6 dwarf: at least 500 times less than the interstellar value, implying that the atmosphere is effectively dust-free. We additionally identify several features that do not appear in the model spectra. Our assessment of the line lists is valuable for atmospheric model applications to high-dispersion, low-SNR, high-background spectra, such as an exoplanet around a star. We demonstrate a significant enhancement in the detection of the CH$_4$ absorption signal in this T6 dwarf with the most up-to-date line lists.
