基于低分辨率LAMOST恒星光譜估算α元素豐度
發(fā)布時間：2018-11-22 11:38
【摘要】：我們發(fā)展了一套基于模板匹配的從低分辨率LAMOST光譜中提取?元素與鐵元素豐度比?]/[Fe的方法。該方法以KURUCZ恒星大氣模型下的合成光譜作為模板,將目標譜與模板譜進行匹配并利用2?最小值確定目標源的?]/[Fe。我們采用的合成光譜的恒星大氣參數(shù)覆蓋范圍為有效溫度(effT)從4000K到8000K,步長100K,表面重力加速度(logg)從0.0到5.0 dex,步長0.25 dex,金屬豐度(HFe]/[)從-4.0到0.5 dex,其中當[Fe/H]小于-1.0 dex時步長為0.2 dex,[Fe/H]大于-1.0 dex時的步長為0.1 dex,?]/[Fe從-0.4到+1.0 dex,步長0.2 dex。我們選擇光譜匹配的波段范圍為440~460nm和500~530nm,因為這倆個波段包含許多對估算?豐度比較敏感的譜線,如Mg I、Ti I、Ti II、Ca I和Si II線。我們采用的光譜自動批處理程序是基于北京大學LAMOST恒星參數(shù)測量程序包(LSP3)擴展而來,以便于從海量LAMOST恒星光譜中提取?]/[Fe。為了驗證我們的方法的可行性,我們將該方法應用到ELODIE和MILES恒星光譜庫,并將所得的?]/[Fe與前人通過高分辨光譜分析得到的結果比較。結果表明,我們估算的?]/[Fe與高分辨光譜分析的結果有-0.13 dex的系統(tǒng)差和約0.08 dex的彌散,二者的差異與恒星大氣參數(shù)沒有明顯的相關性。另外,我們選取了有SDSS光譜觀測的兩個疏散星團和兩個球狀星團的成員星來對我們的方法作進一步驗證,所得結果與將該方法應用到ELODIE和MILES恒星光譜庫得到的結果一致。為了估算我們測定的?]/[Fe的誤差,我們從LAMOST巡天數(shù)據(jù)中挑選出77顆有高分辨率?]/[Fe測量結果的恒星作為定標星以修正系統(tǒng)偏差,并且測量了9萬多顆具有重復觀測光譜的LAMOST恒星的?]/[Fe以詳細研究目前我們的?]/[Fe測量的精度。結果表明,在光譜信噪比大于30的情況下,對于金屬豐度大于-1.0 dex的FG型矮星,我們測量的?]/[Fe的精度優(yōu)于0.1 dex,而金屬豐度小于-1.0 dex的貧金屬恒星對應的?]/[Fe精度稍差,約為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.
【學位授予單位】：河北師范大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P148
本文編號：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.
【學位授予單位】：河北師范大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P148
【參考文獻】
相關期刊論文 前3條
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
，本文編號：2349252
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