主要CoRoT目标HD43587是否处于蒙德最小相位下？
Is the primary CoRoT target HD43587 under a Maunder minimum phase?
摘要：
与太阳活动有关的最神秘的现象之一是所谓的蒙德极小期。这是有史以来太阳黑子计数最低的一次，而且迄今为止从未证实过其他恒星的黑子计数。自从威尔逊山天文台对恒星活动进行光谱观测以来，太阳模拟物HD 43587显示出非常低且明显不变的活动水平，这使它成为蒙德极小的候选者。本文分析了HD 43587色球活动的演化及其演化状况，试图揭示其活动低平的原因。我们使用的活动测量数据集在文献中，并计算活动的S指数从HARPS和NARVAL光谱，推断一个周期。此外，我们还分析了HD 43587的CoRoT光变曲线，并应用陀螺年代学和活动校准来确定其自转周期。最后，基于一个演化模型和推断的旋转周期，我们使用EULAG-MHD代码进行全球的HD 43587的MHD模拟的目的是得到一些见解，其发电机过程。我们确认几乎平坦的活动配置文件，与周期$P_{\mathrm{cyc}} = 10.44\pm3.03$年推导出的S指数时间序列，和一个长期的趋势，可能是一个周期大于50 yrs. It是不可能定义的旋转周期从光变曲线，但gyrochronology和活动校准允许推断间接估计$\overline{P}_{\mathrm{rot}} = 22.6 \pm 1.9$ d。此外，MHD模拟证实了一个振荡发电机的周期与观测和低水平的表面磁活动的良好协议。我们的结论是，这个物体可能正在经历一个“自然”的磁场活动减少，作为其年龄的结果。然而，不能排除HD 43587处于蒙德极小期的可能性。
英文摘要：
One of the most enigmatic phenomena related to solar activity is the so-called Maunder minimum phase. It consists of the lowest sunspot's counting ever registered for the Sun, and never so far confirmed for other stars. Since the spectroscopic observations of stellar activity at the Mount Wilson Observatory, the solar analog HD43587 has shown a very low and apparently invariant activity level, which makes it a Maunder minimum candidate. We analyze the chromospheric activity evolution of HD43587 and its evolutive status, intending to unravel the reasons for this low and flat activity. We use an activity measurements dataset available in the literature, and compute the activity S-index from HARPS and NARVAL spectra, to infer a cycle period. Besides, we analyze the CoRoT light-curve of HD43587, and apply gyrochronology and activity calibrations, to determine its rotation period. Finally, based on an evolutionary model and the inferred rotation period, we use the EULAG-MHD code to perform global MHD simulations of HD43587 with the aim of getting some insights about its dynamo process. We confirm the almost flat activity profile, with a cycle period $P_{\mathrm{cyc}} = 10.44\pm3.03$ yrs deduced from the S-index time series, and a long-term trend that might be a period larger than 50 yrs. It was impossible to define a rotation period from the light-curve, however gyrochronology and activity calibrations allow to infer an indirect estimate of $\overline{P}_{\mathrm{rot}} = 22.6 \pm 1.9$ d. Furthermore, the MHD simulations confirm an oscillatory dynamo with a cycle period in good agreement with the observations and a low level of surface magnetic activity. We conclude that this object might be experiencing a "natural" decrease in magnetic activity as a consequence of its age. Nevertheless, the possibility that HD43587 is in a Maunder minimum phase cannot be ruled out.
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。
