发表机构
INAF-Osservatorio astronomico di Capodimonte; Inter-University Centre for Astronomy and Astrophysics (IUCAA); INFN – Sezione di Pisa; INAF – Osservatorio Astronomico di Abruzzo; Istituto Nazionale di Fisica Nucleare (INFN)—Sez. di Napoli（意大利国家天体物理研究所卡波迪蒙特天文台; 大学间天文学与天体物理学中心; 意大利国家核物理研究所比萨分部; 意大利国家天体物理研究所阿布鲁佐天文台; 意大利国家核物理研究所那不勒斯分部）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用MESA-RSP脉动模型和更新BaSTI演化轨迹，计算RR Lyrae星理论不稳定带边界及PLZ/PWZ关系，发现边界与关系依赖脉动模式、金属丰度及对流方案，无单一对流方案在所有观测平面上最优。
AI 中文摘要
RR Lyrae星（RRLs）是古老恒星种群的重要示踪体，也是关键的距离指示器。为了补充Gaia和Rubin-LSST等大型变星巡天项目，需要利用最先进的恒星演化和脉动模型来更新RRL不稳定带（IS）的拓扑结构及其周期-光度-金属丰度（PLZ）和周期-Wesenheit-金属丰度（PWZ）关系。我们采用更新后的BaSTI水平分支（HB）演化模型，该模型在有效温度和金属丰度上具有更精细的采样，并基于Marconi等人（2015）的方法，使用mesa-rsp模块计算相应的脉动模型。我们利用mesa-rsp计算了一个线性非绝热径向脉动模型网格，覆盖-2.2 <= [Fe/H] <= +0.06 dex的范围。我们探索了七种对流配置，包括Kovacs等人（2024）最近针对RRLs的经验校准方案。我们推导了RRab和RRc脉动星的解析IS边界，并将其转换到多个测光系统（Gaia、OGLE、2MASS和LSST）以及Kiel图中。更新后的演化模型并未显著改变脉动预测：RRab的IS边界与先前结果吻合良好，而RRc的红端边界则略微偏红。IS的宽度随alpha_MLT的增加而系统性减小，且RRc对对流方案的敏感度相对高于RRab。PLZ和PWZ关系在近红外波段也与先前的经验和理论校准结果吻合良好；然而，给出最接近匹配的对流方案随波长而变化。预测的IS边界和PLZ/PWZ关系表现出对脉动模式、金属丰度和对流处理的耦合依赖性，没有单一方案在所有观测平面上均表现最优。
英文摘要
RR Lyraes (RRLs) are important tracers of old stellar populations and crucial distance indicators. To complement large variability surveys such as Gaia and Rubin-LSST, the topology of the RRL instability strip (IS) and their period-luminosity-metallicity (PLZ) and period-Wesenheit-metallicity (PWZ) relations need to be updated using state-of-the-art stellar evolution and pulsation models. We employ the updated set of BaSTI horizontal-branch (HB) evolutionary models, with finer sampling in effective temperature and metallicity, and compute the corresponding pulsation models using the mesa-rsp module building on the approach of Marconi et al. (2015). We compute a grid of linear non-adiabatic radial pulsation models with mesa-rsp, covering -2.2 <= [Fe/H] <= +0.06 dex. Seven convection configurations are explored including the recently empirically calibrated prescription for RRLs by Kovacs et al. (2024). Analytical IS boundaries are derived for RRab and RRc pulsators and transformed into several photometric systems (Gaia, OGLE, 2MASS, and LSST) and the Kiel diagram. The updated evolutionary models do not substantially change the pulsation predictions: RRab IS edges agree well with previous results, while the RRc red edge is slightly redder. The width of the IS decreases systematically with increasing alpha_MLT, and RRc is relatively more sensitive to the convection prescription than RRab. The PLZ and PWZ relations are also in good agreement with previous empirical and theoretical calibrations across the NIR bands; however, the convection prescription giving the closest match is wavelength dependent. The predicted IS boundaries and PLZ/PWZ relations exhibit a coupled dependence on pulsation mode, metallicity, and convective treatment, with no single prescription performing uniformly best across all observational planes.
Comments21 pages, 12 figures, 9 tables, accepted for publication in A&A
