...
首页> 外文期刊>The Astrophysical journal >THE CHEMICAL ABUNDANCES OF STARS IN THE HALO (CASH) PROJECT. II. A SAMPLE OF 14 EXTREMELY METAL-POOR STARS*, **
【24h】

THE CHEMICAL ABUNDANCES OF STARS IN THE HALO (CASH) PROJECT. II. A SAMPLE OF 14 EXTREMELY METAL-POOR STARS*, **

机译:晕(现金)项目中星星的化学丰度。二。 14个极度贫金属之星的样本*,**

获取原文

摘要

We present a comprehensive abundance analysis of 20 elements for 16 new low-metallicity stars from the Chemical Abundances of Stars in the Halo (CASH) project. The abundances have been derived from both Hobby-Eberly Telescope High Resolution Spectrograph snapshot spectra (R ~15, 000) and corresponding high-resolution (R ~35, 000) Magellan Inamori Kyocera Echelle spectra. The stars span a metallicity range from [Fe/H] from –2.9 to –3.9, including four new stars with [Fe/H] –3.7. We find four stars to be carbon-enhanced metal-poor (CEMP) stars, confirming the trend of increasing [C/Fe] abundance ratios with decreasing metallicity. Two of these objects can be classified as CEMP-no stars, adding to the growing number of these objects at [Fe/H] – 3. We also find four neutron-capture-enhanced stars in the sample, one of which has [Eu/Fe] of 0.8 with clear r-process signatures. These pilot sample stars are the most metal-poor ([Fe/H] –3.0) of the brightest stars included in CASH and are used to calibrate a newly developed, automated stellar parameter and abundance determination pipeline. This code will be used for the entire ~500 star CASH snapshot sample. We find that the pipeline results are statistically identical for snapshot spectra when compared to a traditional, manual analysis from a high-resolution spectrum.
机译:我们从晕中恒星的化学丰度(CASH)项目中对16种新的低金属度恒星的20种元素进行了全面的丰度分析。丰度已从Hobby-Eberly望远镜高分辨率光谱仪快照光谱(R〜15,000)和相应的高分辨率(R〜35,000)麦哲伦稻盛盛京瓷Echelle光谱中得出。这些恒星的金属度范围从[Fe / H]从–2.9到–3.9,包括四颗[Fe / H] <–3.7的新星。我们发现四颗恒星是碳增强的贫金属(CEMP)恒星,证实了[C / Fe]丰度比随金属度降低而增加的趋势。这些物体中有两个可以被归类为CEMP无恒星,在[Fe / H] <– 3时,这些物体的数量不断增加。我们还发现样品中有四个中子俘获增强的恒星,其中一个具有[ [Eu / Fe]为0.8,具有清晰的r-过程签名。这些先导样本恒星是CASH中最亮的恒星中金属含量最低的([Fe / H] –3.0),用于校准新开发的自动恒星参数和丰度确定管道。此代码将用于整个〜500星的CASH快照示例。我们发现,与传统的高分辨率光谱手动分析相比,快照光谱的管线结果在统计上是相同的。

著录项

获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号