基于低分辨率LAMOST恒星光谱估算α元素丰度
发布时间：2018-11-22 11:38
【摘要】：我们发展了一套基于模板匹配的从低分辨率LAMOST光谱中提取?元素与铁元素丰度比?]/[Fe的方法。该方法以KURUCZ恒星大气模型下的合成光谱作为模板,将目标谱与模板谱进行匹配并利用2?最小值确定目标源的?]/[Fe。我们采用的合成光谱的恒星大气参数覆盖范围为有效温度(effT)从4000K到8000K,步长100K,表面重力加速度(logg)从0.0到5.0 dex,步长0.25 dex,金属丰度(HFe]/[)从-4.0到0.5 dex,其中当[Fe/H]小于-1.0 dex时步长为0.2 dex,[Fe/H]大于-1.0 dex时的步长为0.1 dex,?]/[Fe从-0.4到+1.0 dex,步长0.2 dex。我们选择光谱匹配的波段范围为440~460nm和500~530nm,因为这俩个波段包含许多对估算?丰度比较敏感的谱线,如Mg I、Ti I、Ti II、Ca I和Si II线。我们采用的光谱自动批处理程序是基于北京大学LAMOST恒星参数测量程序包(LSP3)扩展而来,以便于从海量LAMOST恒星光谱中提取?]/[Fe。为了验证我们的方法的可行性,我们将该方法应用到ELODIE和MILES恒星光谱库,并将所得的?]/[Fe与前人通过高分辨光谱分析得到的结果比较。结果表明,我们估算的?]/[Fe与高分辨光谱分析的结果有-0.13 dex的系统差和约0.08 dex的弥散,二者的差异与恒星大气参数没有明显的相关性。另外,我们选取了有SDSS光谱观测的两个疏散星团和两个球状星团的成员星来对我们的方法作进一步验证,所得结果与将该方法应用到ELODIE和MILES恒星光谱库得到的结果一致。为了估算我们测定的?]/[Fe的误差,我们从LAMOST巡天数据中挑选出77颗有高分辨率?]/[Fe测量结果的恒星作为定标星以修正系统偏差,并且测量了9万多颗具有重复观测光谱的LAMOST恒星的?]/[Fe以详细研究目前我们的?]/[Fe测量的精度。结果表明,在光谱信噪比大于30的情况下,对于金属丰度大于-1.0 dex的FG型矮星,我们测量的?]/[Fe的精度优于0.1 dex,而金属丰度小于-1.0 dex的贫金属恒星对应的?]/[Fe精度稍差,约为0.14 dex。
[Abstract]:We have developed a set of template matching based extraction from low-resolution LAMOST spectra? The ratio of element to iron abundance?] / [Fe]. In this method, the synthetic spectra under the KURUCZ stellar atmosphere model are used as templates, the target spectra and template spectra are matched and 2? Minimum value to determine target source?] / [Fe. The range of atmospheric parameters of the synthesized spectra is from 4000K to 8000K, step length 100K, surface gravity acceleration (logg) from 0.0 to 5.0 dex, step 0.25 dex,. The metal abundance (HFe) / [) ranges from -4.0 to 0.5 dex, where the step size is 0.2 dex, [Fe/H] > -1.0 dex when [Fe/H] is less than -1.0 dex, and the step size is 0.1 dex, when the [Fe/H] is less than -1.0 dex. ] / [Fe from -0.4 to 1.0 dex, step size 0.2 dex. We chose a spectral matching band range of 440~460nm and 500o 530nm because these two bands contain many pairs of estimates? The more sensitive spectral lines, such as Mg I, Ti, I, Ti II,Ca I and Si II, are more sensitive to abundance. Our spectral automatic batch program is based on the Peking University LAMOST stellar Parameter Measurement package (LSP3) to facilitate extraction from massive LAMOST star spectra] / [Fe.] In order to verify the feasibility of our method, we apply this method to the ELODIE and MILES stellar spectral libraries, and compare the results obtained by [Fe] / [Fe] with those obtained by high-resolution spectral analysis. The results show that the systematic difference of -0.13 dex and dispersion of about 0.08 dex are obtained from our estimation of?] / [Fe] / [Fe] and high-resolution spectral analysis, and there is no obvious correlation between the difference between them and the atmospheric parameters of the star. In addition, two open star clusters and two globular star clusters with SDSS spectral observations are selected to further verify our method. The results obtained are consistent with the results obtained by applying the method to the ELODIE and MILES star spectral libraries. To estimate the error of our measurements of? / [Fe, we selected 77 stars with high resolution?] / [Fe measurements as calibration stars to correct system deviations from the LAMOST survey data. In addition, we have measured more than 90000 LAMOST stars with repeated observational spectra] / [Fe] / [Fe] to study in detail the accuracy of our? / [Fe measurements at present. The results show that when the spectral signal-to-noise ratio (SNR) is greater than 30, for the FG dwarf with metal abundance greater than -1.0 dex, the accuracy of our measurement is better than 0.1 dex,. The poor metal stars with a metal abundance of less than -1.0 dex?] / [Fe] / [accuracy is slightly lower, about 0.14 dex.
【学位授予单位】：河北师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P148
本文编号：2349252
[Abstract]:We have developed a set of template matching based extraction from low-resolution LAMOST spectra? The ratio of element to iron abundance?] / [Fe]. In this method, the synthetic spectra under the KURUCZ stellar atmosphere model are used as templates, the target spectra and template spectra are matched and 2? Minimum value to determine target source?] / [Fe. The range of atmospheric parameters of the synthesized spectra is from 4000K to 8000K, step length 100K, surface gravity acceleration (logg) from 0.0 to 5.0 dex, step 0.25 dex,. The metal abundance (HFe) / [) ranges from -4.0 to 0.5 dex, where the step size is 0.2 dex, [Fe/H] > -1.0 dex when [Fe/H] is less than -1.0 dex, and the step size is 0.1 dex, when the [Fe/H] is less than -1.0 dex. ] / [Fe from -0.4 to 1.0 dex, step size 0.2 dex. We chose a spectral matching band range of 440~460nm and 500o 530nm because these two bands contain many pairs of estimates? The more sensitive spectral lines, such as Mg I, Ti, I, Ti II,Ca I and Si II, are more sensitive to abundance. Our spectral automatic batch program is based on the Peking University LAMOST stellar Parameter Measurement package (LSP3) to facilitate extraction from massive LAMOST star spectra] / [Fe.] In order to verify the feasibility of our method, we apply this method to the ELODIE and MILES stellar spectral libraries, and compare the results obtained by [Fe] / [Fe] with those obtained by high-resolution spectral analysis. The results show that the systematic difference of -0.13 dex and dispersion of about 0.08 dex are obtained from our estimation of?] / [Fe] / [Fe] and high-resolution spectral analysis, and there is no obvious correlation between the difference between them and the atmospheric parameters of the star. In addition, two open star clusters and two globular star clusters with SDSS spectral observations are selected to further verify our method. The results obtained are consistent with the results obtained by applying the method to the ELODIE and MILES star spectral libraries. To estimate the error of our measurements of? / [Fe, we selected 77 stars with high resolution?] / [Fe measurements as calibration stars to correct system deviations from the LAMOST survey data. In addition, we have measured more than 90000 LAMOST stars with repeated observational spectra] / [Fe] / [Fe] to study in detail the accuracy of our? / [Fe measurements at present. The results show that when the spectral signal-to-noise ratio (SNR) is greater than 30, for the FG dwarf with metal abundance greater than -1.0 dex, the accuracy of our measurement is better than 0.1 dex,. The poor metal stars with a metal abundance of less than -1.0 dex?] / [Fe] / [accuracy is slightly lower, about 0.14 dex.
【学位授予单位】：河北师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P148
【参考文献】
相关期刊论文 前3条
1 Philippe Prugniel;;Automatic determination of stellar atmospheric parameters and construction of stellar spectral templates of the Guoshoujing Telescope (LAMOST)[J];Research in Astronomy and Astrophysics;2011年08期
2 ;LAMOST spectral survey——An overview[J];Research in Astronomy and Astrophysics;2012年07期
3 Heidi Jo Newberg;Jeffrey L. Carlin;Timothy C. Beers;Norbert Christlieb;Carl J. Grillmair;Puragra Guhathakurta;Hsu-Tai Lee;S忮bastien L忮pine;J. A. Sellwood;Brian Yanny;;LAMOST Experiment for Galactic Understanding and Exploration (LEGUE)——The survey's science plan[J];Research in Astronomy and Astrophysics;2012年07期
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