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Chinese Journal of Astronomy and Astrophysics 2009年第4期9卷 431-448页

作者： Guo-Qing Liu Yan-Chun Liang Li-Cai Deng National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

We obtain the chemical abundances of six barium stars and two CH subgiant stars based on the high signal-to-noise ratio and high resolution EcheUe spectra. The neu-Iron capture process elements Y, Zr, Ba, La and Eu show obvious overabundances relative to the Sun, for example, their [Ba/Fe] values are from 0.45 to 1.27. Other elements, including Na, Mg, A1, Si, Ca, Sc, Ti, V, Cr, Mn and Ni, show comparable abundances to the Solar ones, and their [Fe/H] covers a range from -0.40 to 0.21, which means they belong to the Galactic disk. The predictions of the theoretical model of wind accretion for binary systems can explain the observed abundance patterns of the neutron capture process elements in these stars, which means that their overabundant heavy-elements could be caused by accreting the ejecta of AGB stars, the progenitors of present-day white dwarf companions in binary systems.

关键词： stars abundances-stars atmospheres-stars chemically peculiar-stars evolution-binaries spectroscopic

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Spectroscopic Determination of C,N,and O Abundances of Solar-analog stars Based on the Lines of Hydride Molecules

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Research in Astronomy and Astrophysics 2023年第2期23卷 107-120页

作者： Yoichi Takeda 11-2 Enomachi Naka-kuHiroshima-shi730-0851Japan

Photospheric C,N,and O abundances of 118 solar-analog stars were determined by applying the synthetic-fitting analysis to their spectra in the blue or near-UV region comprising lines of CH,NH,and OH molecules,with an aim of clarifying the behaviors of these abundances in comparison with[Fe/H].It turned out that,in the range of-0.6■[Fe/H]■+0.3,[C/Fe]shows a marginally increasing tendency with decreasing[Fe/H]with a slight upturn around[Fe/H]~0,[N/Fe]tends to somewhat decrease toward lower[Fe/H],and[O/Fe]systematically increases (and thus[C/O]decreases) with a decrease in[Fe/H].While these results are qualitatively consistent with previous determinations mostly based on atomic lines,the distribution centers of these[C/Fe],[N/Fe],and[O/Fe]at the near-solar metallicity are slightly negative by several hundredths of dex,which is interpreted as due to unusual solar abundances possibly related to the planetary formation of our solar ***,clear anomalies are not observed in the[C,N,O/Fe]ratios of planet-host *** out of four very Be-deficient stars were found to show anomalous[C/Fe]or[N/Fe]which may be due to mass transfer from the evolved companion,though its relation to the Be depletion mechanism is still unclear.

关键词： Galaxy evolution-planet-star interactions-stars abundances-stars atmospheres-stars solar-type

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The Stellar Spectra Factory(SSF)Based on SLAM

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Research in Astronomy and Astrophysics 2023年第5期23卷 148-159页

作者： Wei Ji Chao Liu Bo Zhang Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesCASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Institute for Frontier in Astronomy and Astrophysics Beijing Normal UniversityBeijing 100875China

An empirical stellar spectral library with large coverage of stellar parameters is essential for stellar population synthesis and studies of stellar *** this work,we present Stellar Spectra Factory(SSF),a tool to generate empirical-based stellar spectra from arbitrary stellar atmospheric *** relative flux-calibrated empirical spectra can be predicted by SSF given arbitrary effective temperature,surface gravity,and *** constructs the interpolation approach based on the Stellar LAbel Machine,using ATLAS-A library,which contains spectra covering from O type to M type,as the training data *** is composed of four data-driven sub-models to predict empirical stellar ***-model SSF-N can generate spectra from A to K type and some M giant stars,covering 3700stars with the same stellar parameters selected from *** uncertainty becomes 0.31 mag in the i band for SSF-dM when comparing with the st

关键词： methods statistical-techniques spectroscopic-stars atmospheres-stars general

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