标题： 类似太阳的振荡和慢速旋转体EK Eri的磁活动 显示英文标题

标题： Solar-like oscillations and magnetic activity of the slow rotator EK Eri

摘要： 我们旨在理解非径向振荡与恒星磁活动之间的相互作用，并检验对磁活动恒星进行星震学研究的可行性。 我们分析了30年的光度时间序列数据，3年的HARPS径向速度监测数据以及3晚的高采样率HARPS星震学数据。 我们构建了一个高信噪比的HARPS光谱，用于确定大气参数和化学成分。 对不同旋转相位观测的光谱进行分析，以寻找温度或丰度变化的迹象。 从非常高分辨率的CES光谱中推导出投影旋转速度的上限。 我们在EK Eri中检测到频率为最大功率的nu_max = 320+/-32 muHz的振荡，并推导出每个径向模的峰值振幅约为0.15 m/s，这比预期低约3倍。 我们认为磁场可能会抑制低阶模。 无法从现有数据中提取单个频率。 我们得出了精确的大气参数，改进了我们之前的分析。 我们确认主要的光变是由于冷斑造成的，但可能需要考虑其他贡献。 我们建议旋转周期是光变周期的两倍，即P_rot = 2 P_phot = 617.6 d。我们从推导出的参数得出v sin i < 0.40 km/s。 我们还将文献中可用的直接磁场测量时间序列与我们新推导出的光变历元联系起来。 显示英文摘要

摘要： We aim to understand the interplay between non-radial oscillations and stellar magnetic activity and test the feasibility of doing asteroseismology of magnetically active stars. We analyze 30 years of photometric time-series data, 3 years of HARPS radial velocity monitoring, and 3 nights of high-cadence HARPS asteroseismic data. We construct a high-S/N HARPS spectrum that we use to determine atmospheric parameters and chemical composition. Spectra observed at different rotation phases are analyzed to search for signs of temperature or abundance variations. An upper limit on the projected rotational velocity is derived from very high-resolution CES spectra. We detect oscillations in EK Eri with a frequency of the maximum power of nu_max = 320+/-32 muHz, and we derive a peak amplitude per radial mode of ~0.15 m/s, which is a factor of ~3 lower than expected. We suggest that the magnetic field may act to suppress low-degree modes. Individual frequencies can not be extracted from the available data. We derive accurate atmospheric parameters, refining our previous analysis. We confirm that the main light variation is due to cool spots, but that other contributions may need to be taken into account. We suggest that the rotation period is twice the photometric period, i.e., P_rot = 2 P_phot = 617.6 d. We conclude from our derived parameters that v sin i < 0.40 km/s. We also link the time series of direct magnetic field measurements available in the literature to our newly derived photometric ephemeris.