Spectral Irradiance Calibration in the Infrared.VII.New Composite Spectra, Comparison with Model Atmospheres, and Far-Infrared Extrapolations
Spectral Irradiance Calibration in the Infrared.VII.New Composite Spectra, Comparison with Model Atmospheres, and Far-Infrared Extrapolations
复制标题
红外光谱辐照度校准。VII.新的复合光谱、与模型大气的比较以及远红外外推
DOI：
10.1086/118180
复制
发表时间：
1996
期刊：
影响因子：
--
通讯作者：
J. Bregman
中科院分区：
文献类型：
--
作者：
M. Cohen;F. Witteborn;D. Carbon;J. Davies;D. Wooden;J. Bregman
我们提出了五个新的绝对校准的连续恒星光谱构造尽可能从地面观测到的光谱碎片，柯伊伯机载天文台（KAO），和IRAS低分辨率光谱仪。这些恒星--α Boo、γ Dra、α Cet、γ Cru和μ UMa--增强了我们公布的K和早期M巨星的绝对校准光谱。所有光谱都有一个共同的校准谱系。一个修订后的复合物的α Boo已被构造从更高质量的光谱片段比我们以前发表的。伽马射线的光谱是根据红外空间天文台（ISO）上仪器的需要而创建的;这颗星星位于黄道北极附近，使它在整个使命中都非常明显。我们比较了我们所有的低分辨率复合光谱与库鲁茨模型大气，并找到良好的协议的形状，与明显的例外的SiO基本面，仍然缺乏当前网格的模型大气。在这些模型中，CO的基本原理似乎有点太深了，但这可能反映了我们使用的是太阳金属丰度的通用模型，而不是针对单个恒星金属丰度的模型。从这些光谱和模型得到的角直径与最佳观测直径非常一致。光谱观测证实了我们采用的天狼星和织女星模型的比例。我们比较IRAS通量预测从我们的冷恒星光谱与观察到的，并得出结论，在12和25微米，IRAS测量的通量密度应分别向下修订约4.1%和5.7%，与我们的绝对校准一致。我们已经提供了这些光谱的外推连续版本到300微米，直接支持ISO（PHT和LWS仪器）。这些光谱与60和100微米处的IRAS通量密度一致。
We present five new absolutely calibrated continuous stellar spectra constructed as far as possible from spectral fragments observed from the ground, the Kuiper Airborne Observatory (KAO), and the IRAS Low Resolution Spectrometer. These stars-alpha Boo, gamma Dra, alpha Cet, gamma Cru, and mu UMa-augment our six, published, absolutely calibrated spectra of K and early-M giants. All spectra have a common calibration pedigree. A revised composite for alpha Boo has been constructed from higher quality spectral fragments than our previously published one. The spectrum of gamma Dra was created in direct response to the needs of instruments aboard the Infrared Space Observatory (ISO); this star's location near the north ecliptic pole renders it highly visible throughout the mission. We compare all our low-resolution composite spectra with Kurucz model atmospheres and find good agreement in shape, with the obvious exception of the SiO fundamental, still lacking in current grids of model atmospheres. The CO fundamental seems slightly too deep in these models, but this could reflect our use of generic models with solar metal abundances rather than models specific to the metallicities of the individual stars. Angular diameters derived from these spectra and models are in excellent agreement with the best observed diameters. The ratio of our adopted Sirius and Vega models is vindicated by spectral observations. We compare IRAS fluxes predicted from our cool stellar spectra with those observed and conclude that, at 12 and 25 microns, flux densities measured by IRAS should be revised downwards by about 4.1% and 5.7%, respectively, for consistency with our absolute calibration. We have provided extrapolated continuum versions of these spectra to 300 microns, in direct support of ISO (PHT and LWS instruments). These spectra are consistent with IRAS flux densities at 60 and 100 microns.