发表机构
Centre for Astrophysics, University of Southern Queensland（南昆士兰大学天体物理中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究通过星族合成模型考虑多种因素，解释中等质量恒星观测特性。结合多种效应构建模型，验证特性映射。推断不稳定带，研究周期-光度关系，预测星震大分离分布，表明星族合成可联系恒星多方面特性。
AI 中文摘要
解释中等质量恒星的观测特性需要考虑自转、双星性、固有星族多样性和测量不确定性。我们在1.4 - 2.5 M$_{\odot}$恒星的星族合成模型中结合了这些效应，该模型包含盾牌座δ型变星的脉动特性。合成星族成功再现了年轻星协中观测到的恒星分布，验证了固有和观测恒星特性之间的映射关系。通过匹配合成和观测星族，我们推断出一个半经验的盾牌座δ型变星不稳定带，其比广泛使用的理论规定系统地更热，这意味着盾牌座δ型变星平均比之前假设的质量大0.1 M$_{\odot}$，95%的星族质量范围约为1.50 - 2.30 M$_{\odot}$。然后我们研究了盾牌座δ型变星的周期-光度关系，并用混合模型再现了最近发现的第二条脊，其中约三分之一的恒星以第五或第六径向泛音为主导模式，在更年轻的星族中这一比例增加。相比之下，未分辨的双星性无法解释第二条脊。最后，我们预测了星震大分离$\Delta\nu$的全星族分布，发现峰值在6到7 d$^{-1}$之间，与最近的观测一致。我们还证明，$\Delta\nu$用阶梯技术测量最可靠，而自相关方法单独使用时可能会产生虚假探测。这些结果表明，星族合成提供了一个强大的框架，用于解释盾牌座δ型变星的星族，并将恒星演化、脉动和观测联系起来。
英文摘要
Interpreting the observed properties of intermediate-mass stars requires accounting for rotation, binarity, intrinsic population diversity, and measurement uncertainty. We combine these effects in population-synthesis models of 1.4-2.5 M$_{\odot}$ stars that include pulsation properties of $δ$ Sct variables. The synthetic populations successfully reproduce the distributions of stars observed in young associations, validating the mapping between intrinsic and observed stellar properties. Using these models, we infer a semi-empirical $δ$ Sct instability strip by matching synthetic and observed populations. The resulting instability strip is systematically hotter than widely used theoretical prescriptions, implying that $δ$ Sct stars are on average 0.1 M$_{\odot}$ more massive than previously assumed, with 95% of the population spanning approximately 1.50-2.30 M$_{\odot}$. We then investigate the $δ$ Sct period-luminosity relation and reproduce its recently identified second ridge with mixture models in which roughly one-third of stars have the fifth or sixth radial overtone as their dominant mode; the fraction increases in younger populations. In contrast, unresolved binarity does not account for the second ridge. Finally, we predict the population-wide distribution of asteroseismic large separations, $Δν$, finding a peak between 6 and 7 d$^{-1}$, in agreement with recent observations. We also demonstrate that $Δν$ is most reliably measured with the échelle technique, while autocorrelation methods can produce spurious detections when used in isolation. These results show that population synthesis provides a powerful framework for interpreting populations of $δ$ Sct stars and for linking stellar evolution, pulsation, and observation.
Commentssubmitted to MNRAS; v2 incorporates in-text clarifications from the refereeing process
