发表机构
Memorial University of Newfoundland & Labrador; Harvard & Smithsonian Astrophysical Observatory（纽芬兰与拉布拉多纪念大学; 哈佛-史密森天体物理台）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究SV Per、RW Cam、KN Cen三颗造父变星双星的年龄差异，用MESA代码模拟合并过程，提出部分造父变星可能是主序星合并形成的年轻化产物，KN Cen符合单星演化。
AI 中文摘要
SV Per、RW Cam和KN Cen是银河系经典造父变星，均处于包含B型伴星的双星系统中。每个系统都存在“表观年龄差异”，即造父变星的年龄明显小于其伴星。我们使用MESA代码计算恒星演化轨迹，并将其与赫罗图上的这些恒星进行比对，以估算它们的质量和对应年龄。我们发现，在其中两个系统中，伴星的年龄约为造父变星的1.5倍至2倍，这表明这些造父变星可能是由两颗主序星合并后形成的“年轻化”产物，之后继续演化。当我们重新评估紫外观测结果并发现KN Cen的伴星温度比之前测量的更高时，发现第三个系统KN Cen与单星演化模型相符。我们使用MESA代码对每个系统进行测试：先演化一个单星模型，再在主序阶段快速吸积质量以模拟合并过程，随后继续演化模型直至其参数与造父变星的参数一致。结果与造父变星最初为合并产物的假设相符。最后，我们讨论了检验合并假设的潜在观测方法。
英文摘要
SV Per, RW Cam, and KN Cen are Galactic classical Cepheids found in binary systems along with B-type companions. Each system exhibits an ``apparent age discrepancy", where the Cepheid appears significantly younger than its companion. We compute stellar evolution tracks using the MESA code and compare them with these stars on the Hertzsprung-Russell diagram to estimate the masses and the corresponding ages. We find that, for two of the systems, the companions appear to be between 1.5 times to double the age of the Cepheids, suggesting that the Cepheids may be rejuvenated merger products of two main-sequence stars that have since evolved. We find that the third system KN Cen is consistent with single star evolution when we reevaluate ultraviolet observations and find that the companion is hotter than previously measured. We test this idea using the MESA code for each system by evolving a single star model and rapidly accreting mass on the main sequence to emulate a merger, and then continuing the evolution until the model is consistent with the parameters of the Cepheids. The results are consistent with the hypothesis that the Cepheids were originally merger products. We conclude with a discussion of potential observational tests of the merger hypothesis.
Comments13 pages, 8 figures, 2 tables, submitted to AAS Journals
