Asteroseismic constraints on active latitudes of solar-type stars: HD 173701 has active bands at higher latitudes than the Sun
Asteroseismic constraints on active latitudes of solar-type stars: HD 173701 has active bands at higher latitudes than the Sun
复制标题
星震对太阳型恒星活动纬度的限制：HD 173701在比太阳更高的纬度处具有活动带
DOI：
10.1093/mnras/stz672
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发表时间：
2019
影响因子：
4.8
通讯作者：
Cunha M
中科院分区：
文献类型：
--
作者：
Cunha M
我们提出了一种确定太阳型恒星活动带位置的新方法，该方法利用恒星周期引起的可探测的类太阳振荡的频移。当近地表活动呈非均匀分布时，不同角度和方位角阶的振动模态频率会发生不同程度的偏移。我们利用这个简单的概念，结合近地表活动的空间分布模型，开发了两种方法，利用频移来推断活动带的最小和最大纬度。我们的方法对存在显著磁通量的纬度范围作出反应，在微弱的基础短暂磁通量水平之上。我们利用太阳作为恒星的日震数据和人工数据验证了我们能够在太阳的情况下得出准确的推论。然后，我们将我们的方法应用于类似太阳的HD 173701上的开普勒数据，发现它的活动波段跨越的纬度范围比太阳上的波段宽得多。
We present a new method for determining the location of active bands of latitude on solar-type stars, which uses stellar-cycle-induced frequency shifts of detectable solar-like oscillations. When near-surface activity is distributed in a non-homogeneous manner, oscillation modes of different angular degree and azimuthal order will have their frequencies shifted by different amounts. We use this simple concept, coupled to a model for the spatial distribution of the near-surface activity, to develop two methods that use the frequency shifts to infer minimum and maximum latitudes for the active bands. Our methods respond to the range in latitude over which there is significant magnetic flux present, over and above weak basal ephemeral flux levels. We verify that we are able to draw accurate inferences in the solar case, using Sun-as-a-star helioseismic data and artificial data. We then apply our methods toKeplerdata on the solar analogue HD 173701, and find that its active bands straddle a much wider range in latitude than do the bands on the Sun.