arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新，休息一下吧，周末愉快~~
arXiv 2307.04086astro-ph.SRastro-ph.GA
收藏

LAMOST与GALAH观测的FGK矮星年龄：考虑氧增丰的影响

Age of FGK Dwarfs Observed with LAMOST and GALAH: Considering the Oxygen Enhancement

Tiancheng Sun, Zhishuai Ge, Xunzhou Chen, Shaolan Bi, Tanda Li, Xianfei Zhang, Yaguang Li, Yaqian Wu, Sarah A. Bird, Ferguson J. W., Jianzhao Zhou, Lifei Ye, Li… 展开作者

Tiancheng Sun, Zhishuai Ge, Xunzhou Chen, Shaolan Bi, Tanda Li, Xianfei Zhang, Yaguang Li, Yaqian Wu, Sarah A. Bird, Ferguson J. W., Jianzhao Zhou, Lifei Ye, Liu Long, Jinghua Zhang

备注：
18 pages, 12 figures, accepted for publication in ApJS
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

AI总结：

本研究通过构建将氧丰度作为独立输入的恒星模型，估计LAMOST和GALAH中FGK矮星的年龄，发现考虑氧丰度后年龄平均差异约9%，并揭示了年龄差异与[Fe/H]、[O/α]的相关性及年轻星族更富氧的化学演化趋势。

摘要：

氧丰度的变化可能影响由模型推断的年龄。本研究旨在考虑观测到的氧丰度来估计矮星的年龄。为刻画67,503颗LAMOST和4,006颗GALAH FGK型矮星，我们构建了一个将氧丰度作为独立模型输入的恒星模型网格。与使用常用的α增丰模型确定的年龄相比，我们发现当考虑观测到的氧丰度时，平均差异约为9%。两类模型之间的年龄差异与[Fe/H]和[O/α]相关，并且在[Fe/H] ≲ -0.6 dex的恒星上相对显著。通常，[O/α]变化0.2 dex会使富金属（-0.2 < [Fe/H] < 0.2）恒星的年龄估计改变约10%，使相对贫金属（-1 < [Fe/H] < -0.2）恒星的年龄估计改变约15%。在[Fe/H] < 0.1 dex且[O/α] ~ -0.2 dex的低氧恒星中，许多恒星的年龄分数差异≥10%，甚至高达27%。高氧恒星（[O/α] ~ 0.4 dex）在[Fe/H] ≲ -0.6 dex时的年龄分数差异可达-33%至-42%。我们还分析了这些恒星的化学性质。我们发现LAMOST和GALAH恒星从7.5-9 Gyr到5-6.5 Gyr的[Fe/H]随年龄呈下降趋势。这些恒星的[O/Fe]从7.5-9 Gyr到3-4 Gyr随年龄减小而增加，表明较年轻的星族更富氧。

英文摘要：

Varying oxygen abundance could impact the modeling-inferred ages. This work aims to estimate the ages of dwarfs considering observed oxygen abundance. To characterize 67,503 LAMOST and 4,006 GALAH FGK-type dwarf stars, we construct a grid of stellar models which take into account oxygen abundance as an independent model input. Compared with ages determined with commonly-used $α$-enhanced models, we find a difference of $\sim$9% on average when the observed oxygen abundance is considered. The age differences between the two types of models are correlated to [Fe/H] and [O/$α$], and they are relatively significant on stars with [Fe/H] $\lesssim$ -0.6 dex. Generally, varying 0.2 dex in [O/$α$] will alter the age estimates of metal-rich (-0.2 $<$ [Fe/H] $<$ 0.2) stars by $\sim$10%, and relatively metal-poor (-1 $<$ [Fe/H] $<$ -0.2) stars by $\sim$15%. Of the low-O stars with [Fe/H] $<$ 0.1 dex and [O/$α$] $\sim$ -0.2 dex, many have fractional age differences of $\geq$ 10%, and even reach up to 27%. The fractional age difference of high-O stars with [O/$α$] $\sim$ 0.4 dex reaches up to -33% to -42% at [Fe/H] $\lesssim$ -0.6 dex. We also analyze the chemical properties of these stars. We find a decreasing trend of [Fe/H] with age from 7.5-9 Gyr to 5-6.5 Gyr for the stars from the LAMOST and GALAH. The [O/Fe] of these stars increases with decreasing age from 7.5-9 Gyr to 3-4 Gyr, indicating that the younger population is more O-rich.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑