Photometric magnetic-activity metrics tested with the Sun: application to Kepler M dwarfs
Photometric magnetic-activity metrics tested with the Sun: application to Kepler M dwarfs
复制标题
用太阳测试的光度磁活动指标：在开普勒 M 矮星上的应用
DOI：
10.1051/swsc/2014011
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发表时间：
2014
影响因子：
3.3
通讯作者：
Tugdual Ceillier
中科院分区：
文献类型：
--
作者：
S. Mathur;D. Salabert;R. García;Tugdual Ceillier
开普勒任务一直在提供高质量的光度数据，这导致了系外行星搜索和恒星物理方面的许多突破。恒星的磁活动是自转、对流和磁场相互作用的结果。如果我们想要更好地了解恒星的磁活动，约束这些过程是很重要的。利用太阳，我们想要测试一个基于光度响应分析的磁活动指数，然后将其应用于开普勒观测到的M颗矮星的样本。我们通过测量整个时间序列的标准差S的ph值来估计全球恒星磁活动指数。由于恒星的可变性可能与对流、脉动或磁性有关，我们需要确保该指数主要考虑磁性效应。我们将另一个恒星磁活动指数定义为较短的子序列的标准差的平均值，其长度由恒星的自转周期决定。通过这种方式，我们可以确保测量到的光度可变性与穿过可见恒星盘的恒星黑子有关。这一新指数与基于Morlet小波的时频分析相结合，使我们能够确定磁活动周期的存在。我们测量了开普勒观测到的太阳和34M矮星的磁指数。不出所料，我们得到了这项工作中研究的M矮星样本比太阳活跃得多。此外，我们还发现自转周期与磁指数之间存在较小的相关性。最后，通过将时频分析与相图相结合，我们发现了这些恒星表面存在活动经度的长寿命特征。
The Kepler mission has been providing high-quality photometric data leading to many breakthroughs in the exoplanet search and in stellar physics. Stellar magnetic activity results from the interaction between rotation, convection, and magnetic field. Constraining these processes is important if we want to better understand stellar magnetic activity. Using the Sun, we want to test a magnetic activity index based on the analysis of the photometric response and then apply it to a sample of M dwarfs observed by Kepler . We estimate a global stellar magnetic activity index by measuring the standard deviation of the whole time series, S ph . Because stellar variability can be related to convection, pulsations or magnetism, we need to ensure that this index mostly takes into account magnetic effects. We define another stellar magnetic activity index as the average of the standard deviation of shorter subseries which lengths are determined by the rotation period of the star. This way we can ensure that the measured photometric variability is related to starspots crossing the visible stellar disc. This new index combined with a time-frequency analysis based on the Morlet wavelets allows us to determine the existence of magnetic activity cycles. We measure magnetic indexes for the Sun and for 34 M dwarfs observed by Kepler . As expected, we obtain that the sample of M dwarfs studied in this work is much more active than the Sun. Moreover, we find a small correlation between the rotation period and the magnetic index. Finally, by combining a time-frequency analysis with phase diagrams, we discover the presence of long-lived features suggesting the existence of active longitudes on the surface of these stars.
DOI：
10.1088/0004-637x/749/2/152
发表时间：
2012-02
期刊：
The Astrophysical Journal
影响因子：
--
作者：
S. Mathur;T. Metcalfe;M. Woitaszek;H. Bruntt;G. Verner;J. Christensen-Dalsgaard;J. Christensen-Dalsgaard;O. Creevey;G. Doğan;G. Doğan;S. Basu;C. Karoff;C. Karoff;D. Stello;T. Appourchaux;T. Campante;T. Campante;W. Chaplin;R. García;T. Bedding;O. Benomar;A. Bonanno;S. Deheuvels;Y. Elsworth;P. Gaulme;J. Guzik;R. Handberg;S. Hekker;S. Hekker;W. Herzberg;M. Monteiro;L. Piau;P. Quirion;C. Régulo;C. Régulo;M. Roth;D. Salabert;A. Serenelli;Michael Thompson;R. Trampedach;T. White;J. Ballot;I. Brandao;J. Molenda–Żakowicz;H. Kjeldsen;J. Twicken;K. Uddin;B. Wohler
通讯作者：
S. Mathur;T. Metcalfe;M. Woitaszek;H. Bruntt;G. Verner;J. Christensen-Dalsgaard;J. Christensen-Dalsgaard;O. Creevey;G. Doğan;G. Doğan;S. Basu;C. Karoff;C. Karoff;D. Stello;T. Appourchaux;T. Campante;T. Campante;W. Chaplin;R. García;T. Bedding;O. Benomar;A. Bonanno;S. Deheuvels;Y. Elsworth;P. Gaulme;J. Guzik;R. Handberg;S. Hekker;S. Hekker;W. Herzberg;M. Monteiro;L. Piau;P. Quirion;C. Régulo;C. Régulo;M. Roth;D. Salabert;A. Serenelli;Michael Thompson;R. Trampedach;T. White;J. Ballot;I. Brandao;J. Molenda–Żakowicz;H. Kjeldsen;J. Twicken;K. Uddin;B. Wohler
影响因子：
6.5
作者：
T. Reinhold;A. Reiners;G. Basri
通讯作者：
T. Reinhold;A. Reiners;G. Basri
六颗开普勒亚巨星和年轻红巨星内自转剖面径向依赖性的地震约束
影响因子：
6.5
作者：
Deheuvels;Doğan;Goupil
通讯作者：
Goupil