Activity Cycles of Southern Asteroseismic Targets
Activity Cycles of Southern Asteroseismic Targets
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南部星震目标的活动周期
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
M. Rempel
中科院分区：
文献类型：
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作者：
T. Metcalfe;P. Judge;S. Basu;T. Henry;D. Soderblom;M. Knoelker;M. Rempel
威尔逊山Ca HK巡天揭示了大量太阳型恒星的磁活动变化，时间尺度从2.5年到25年不等。这种广泛的循环周期被认为反映了不同质量和年龄的恒星的旋转特性和表面对流区深度的差异。天体地震数据将很快提供对单个恒星的这些量的直接测量，但许多最有希望的目标位于南部天空（例如，alpha Cen A & B、beta Hyi、mu Ara、tau Cet、nu Ind），而长期磁活动周期调查主要局限于北部。2007年，我们开始使用SMARTS 1.5米望远镜对57颗南太阳型恒星的Ca II H & K发射进行长期监测，以测量它们的磁活动周期和可能的旋转特性。这一样本包括目前定于2012年开始运行的恒星振荡网络小组将观测的最有可能的南部小行星地震目标。我们提出了选定的结果，从头两年的调查，并从较长的时间基线抽样的单历元调查在1992年进行。
The Mount Wilson Ca HK survey revealed magnetic activity variations in a large sample of solar-type stars with timescales ranging from 2.5 to 25 years. This broad range of cycle periods is thought to reflect differences in the rotational properties and the depths of the surface convection zones for stars with various masses and ages. Asteroseismic data will soon provide direct measurements of these quantities for individual stars, but many of the most promising targets are in the southern sky (e.g., alpha Cen A & B, beta Hyi, mu Ara, tau Cet, nu Ind), while long-term magnetic activity cycle surveys are largely confined to the north. In 2007 we began using the SMARTS 1.5-m telescope to conduct a long-term monitoring campaign of Ca II H & K emission for a sample of 57 southern solar-type stars to measure their magnetic activity cycles and their rotational properties when possible. This sample includes the most likely southern asteroseismic targets to be observed by the Stellar Oscillations Network Group (SONG), currently scheduled to begin operations in 2012. We present selected results from the first two years of the survey, and from the longer time baseline sampled by a single-epoch survey conducted in 1992.