【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(biāo)譜與模板譜進(jìn)行匹配并利用2?最小值確定目標(biāo)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(zhǎng)100K,表面重力加速度(logg)從0.0到5.0 dex,步長(zhǎng)0.25 dex,金屬豐度(HFe]/[)從-4.0到0.5 dex,其中當(dāng)[Fe/H]小于-1.0 dex時(shí)步長(zhǎng)為0.2 dex,[Fe/H]大于-1.0 dex時(shí)的步長(zhǎng)為0.1 dex,?]/[Fe從-0.4到+1.0 dex,步長(zhǎng)0.2 dex。我們選擇光譜匹配的波段范圍為440~460nm和500~530nm,因?yàn)檫@倆個(gè)波段包含許多對(duì)估算?豐度比較敏感的譜線(xiàn),如Mg I、Ti I、Ti II、Ca I和Si II線(xiàn)。我們采用的光譜自動(dòng)批處理程序是基于北京大學(xué)LAMOST恒星參數(shù)測(cè)量程序包(LSP3)擴(kuò)展而來(lái),以便于從海量LAMOST恒星光譜中提取?]/[Fe。為了驗(yàn)證我們的方法的可行性,我們將該方法應(yīng)用到ELODIE和MILES恒星光譜庫(kù),并將所得的?]/[Fe與前人通過(guò)高分辨光譜分析得到的結(jié)果比較。結(jié)果表明,我們估算的?]/[Fe與高分辨光譜分析的結(jié)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(méi)有明顯的相關(guān)性。另外,我們選取了有SDSS光譜觀測(cè)的兩個(gè)疏散星團(tuán)和兩個(gè)球狀星團(tuán)的成員星來(lái)對(duì)我們的方法作進(jìn)一步驗(yàn)證,所得結(jié)果與將該方法應(yīng)用到ELODIE和MILES恒星光譜庫(kù)得到的結(jié)果一致。為了估算我們測(cè)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(cè)量結(jié)果的恒星作為定標(biāo)星以修正系統(tǒng)偏差,并且測(cè)量了9萬(wàn)多顆具有重復(fù)觀測(cè)光譜的LAMOST恒星的?]/[Fe以詳細(xì)研究目前我們的?]/[Fe測(cè)量的精度。結(jié)果表明,在光譜信噪比大于30的情況下,對(duì)于金屬豐度大于-1.0 dex的FG型矮星,我們測(cè)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(duì)應(yīng)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(xué)位授予單位】：河北師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：P148

【參考文獻(xiàn)】

相關(guān)期刊論文 前3條

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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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本文編號(hào)：2349252