Modeling the RV jitter of early M dwarfs using tomographic imaging
Modeling the RV jitter of early M dwarfs using tomographic imaging
复制标题
使用断层扫描成像模拟早期 M 矮星的 RV 抖动
DOI：
10.1093/mnras/stw1346
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发表时间：
2016
影响因子：
4.8
通讯作者：
I. Boisse
中科院分区：
文献类型：
--
作者：
'E.M. H'ebrard;J. Donati;X. Delfosse;J. Morin;C. Moutou;I. Boisse
在本文中，我们展示了如何使用断层扫描成像（塞曼多普勒成像，ZDI）来表征恒星活动和磁场拓扑，最终过滤掉 M 矮星中度旋转体的径向速度（RV）活动抖动。这项工作基于使用 HARPS-Pol 和 NARVAL 对五个弱活跃早期 M 矮星（GJ 205、GJ 358、GJ 410、GJ479、GJ 846）样本的分光偏振观测。这些恒星的 v sin i 和 RV 抖动分别在 1-2 km/s 和 2.7-10.0 m/s rms 范围内。使用 ZDI 的修改版本应用于非偏振谱线的相位分辨最小二乘解卷积 (LSD) 剖面集，我们能够表征恒星表面活跃区域的分布。我们发现暗点覆盖的样本恒星总表面不到 2%。我们的技术能够有效地对活动抖动的旋转调制分量进行建模，并成功将该分量的幅度降低了 2-3 倍的典型系数，在最佳情况下最高可达 6 倍。根据圆偏振光谱的旋转调制时间序列和 ZDI，我们还重建了大规模磁场拓扑。这些磁场表明，在活跃的 M 矮星中观察到的发电机过程的双稳定性也可能对中等活跃的 M 矮星起作用。将光点分布与场拓扑进行比较表明，引起活动抖动的暗点集中在磁极和/或赤道，这将通过更大样本的未来数据得到证实。
In this paper we show how tomographic imaging (Zeeman Doppler Imaging, ZDI) can be used to characterize stellar activity and magnetic field topologies, ultimately allowing to filter out the radial velocity (RV) activity jitter of M-dwarf moderate rotators. This work is based on spectropolarimetric observations of a sample of five weakly-active early M-dwarfs (GJ 205, GJ 358, GJ 410, GJ479, GJ 846) with HARPS-Pol and NARVAL. These stars have v sin i and RV jitters in the range 1-2 km/s and 2.7-10.0 m/s rms respectively. Using a modified version of ZDI applied to sets of phase-resolved Least-Squares- Decon- volved (LSD) profiles of unpolarized spectral lines, we are able to characterize the distribution of active regions at the stellar surfaces. We find that darks spots cover less than 2% of the total surface of the stars of our sample. Our technique is e cient at modeling the rotationally mod- ulated component of the activity jitter, and succeeds at decreasing the amplitude of this com- ponent by typical factors of 2-3 and up to 6 in optimal cases. From the rotationally modulated time-series of circularly polarized spectra and with ZDI, we also reconstruct the large-scale magnetic field topology. These fields suggest that bi-stability of dynamo processes observed in active M dwarfs may also be at work for moderately active M dwarfs. Comparing spot distributions with field topologies suggest that dark spots causing activity jitter concentrate at the magnetic pole and/or equator, to be confirmed with future data on a larger sample.
主序星近地表对流的三维模拟-III 小尺度磁通量集中结构
影响因子：
6.5
作者：
Schüssler;Cameron;Reiners
通讯作者：
Reiners
用视向速度法探测低质量恒星周围的行星
DOI：
10.1088/0004-637x/710/1/432
发表时间：
2010
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Reiners;Dreizler;Seifahrt;Czesla
通讯作者：
Czesla
影响因子：
6.5
作者：
Baraffe, Isabelle;Homeier, Derek;Chabrier, Gilles
通讯作者：
Chabrier, Gilles