SVEEEETIES: singular vector expansion to estimate Earth-like exoplanet temperatures from infrared emission spectra
SVEEEETIES: singular vector expansion to estimate Earth-like exoplanet temperatures from infrared emission spectra
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SVEEEETIES：奇异向量展开从红外发射光谱估计类地系外行星温度
DOI：
10.1051/0004-6361/201936511
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发表时间：
2020
影响因子：
6.5
通讯作者：
J. Grenfell
中科院分区：
文献类型：
--
作者：
F. Schreier;S. Städt;F. Wunderlich;M. Godolt;J. Grenfell
背景 系外行星的详细特征显然正在走向行星科学的前沿。温度是理解大气物理和化学的关键标志。目标我们的目标是使用大口径未来太空望远镜，从围绕 G、K 和 M 星运行的类地系外行星的热发射的二次日食光谱观测中反演以 N2-O2 为主的大气温度。方法使用逐行辐射传输代码来生成合成热红外 (TIR) 观测结果。大气温度通过基向量的展开来近似，基向量由包含代表性分布的矩阵的奇异值分解定义。使用非线性最小二乘拟合来估计未知的膨胀系数。结果对 TIR 光谱中的 4.3 和 15μm CO2 波段进行分析，即使在中等分辨率下信噪比为 5 的情况下也可以推断温度。对流层上层和平流层中下层与真实温度的偏差通常在几个开尔文的范围内，高层大气偏差较大，对流层下层偏差较少。尽管在大多数情况下两个波段的性能相当，但由于恒星与行星之间的对比度增加，长波 TIR 比短波更有利。詹姆斯·韦伯太空望远镜 (JWST) 仪器提供的高光谱分辨率对于保持对高层大气的灵敏度非常重要。此外，选择一组适当的基函数也是关键。结论与了解宜居性相关的中层大气温度可以通过分辨率至少为 1000（理想情况下约为 2500）的红外发射光谱来适当表征。即使对于 JWST 来说，获得必要的信噪比也将是一项挑战，但是，对于未来的太空任务来说，例如起源太空望远镜或系外行星的大型干涉仪，这可能是可行的。同时，与一组适当的基函数拟合的最小二乘法也适用于其他类别的行星。
ContextDetailed characterizations of exoplanets are clearly moving to the forefront of planetary science. Temperature is a key marker for understanding atmospheric physics and chemistry.AimsWe aim to retrieve temperatures of N2-O2dominated atmospheres from secondary eclipse spectroscopic observations of the thermal emission of Earth-like exoplanets orbiting G-, K-, and M-stars, using large-aperture future space telescopes.MethodsA line-by-line radiative transfer code was used to generate synthetic thermal infrared (TIR) observations. The atmospheric temperature is approximated by an expansion with the base vectors defined by a singular value decomposition of a matrix comprising representative profiles. A nonlinear least squares fitting was used to estimate the unknown expansion coefficients.ResultsAnalysis of the 4.3 and 15μm CO2bands in the TIR spectra permits the inference of temperatures even for low signal-to-noise ratios of 5 at medium resolution. Deviations from the true temperature in the upper troposphere and lower-to-mid stratosphere are usually in the range of a few Kelvin, with larger deviations in the upper atmosphere and, less often, in the lower troposphere. Although the performance of the two bands is equivalent in most cases, the longwave TIR is more favorable than the shortwave due to increased star-planet contrast. A high spectral resolution, as provided by theJames WebbSpace Telescope (JWST) instruments, is important for retaining sensitivity to the upper atmosphere. Furthermore, the selection of an appropriate set of base functions is also key.ConclusionsTemperature in the mid-atmosphere, relevant for understanding habitability, can be suitably characterized by infrared emission spectroscopy with a resolution of at least 1000 (ideally ≈2500). Obtaining the necessary signal-to-noise ratio will be challenging even for JWST, however, it could be feasible with future space missions, such as the Origins Space Telescope or the Large Interferometer for Exoplanets. In the meantime, a least squares fitting with an appropriate set of base functions is also applicable for other classes of planets.
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影响因子：
3
作者：
D. Defrére;A. Léger;O. Absil;C. Beichman;B. Biller;W. Danchi;K. Ergenzinger;C. Eiroa;S. Ertel
通讯作者：
D. Defrére;A. Léger;O. Absil;C. Beichman;B. Biller;W. Danchi;K. Ergenzinger;C. Eiroa;S. Ertel
太阳系外行星的高色散光谱：从热木星中的二氧化碳到地外行星中的氧气
DOI：
--
发表时间：
2014
期刊：
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
影响因子：
--
作者：
I. Snellen
通讯作者：
I. Snellen
影响因子：
1.9
作者：
T. von Clarmann;G. Echle
通讯作者：
G. Echle
影响因子：
3.8
作者：
R. Lindstrot;R. Preusker
通讯作者：
R. Lindstrot;R. Preusker
静止盖地球的宜居性
影响因子：
6.5
作者：
Godolt;Stracke;Ruedas;Grenfell;Höning;Nikolaou;Breuer
通讯作者：
Breuer