Magnetic fields and differential rotation on the pre-main sequence - III. The early-G star HD 106506
Magnetic fields and differential rotation on the pre-main sequence - III. The early-G star HD 106506
复制标题
前主序带上的磁场和差分旋转 - III。
DOI：
10.1111/j.1365-2966.2011.18366.x
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发表时间：
2011
影响因子：
4.8
通讯作者：
Nick Dunstone
中科院分区：
文献类型：
--
作者：
I. Waite;S. Marsden;S. Marsden;Brad Carter;R. Hart;J. Donati;J. V'elez;M. Semel;Nick Dunstone
本文介绍了主序前星星HD 106506的测光和分光偏振测量。利用肯特山天文台（MKO）的观测资料，导出了该天体的测光自转周期为1.416 ± 0.133d。利用3.9米英澳望远镜（AAT）获得的分光偏振数据，通过塞曼多普勒成像（ZDI）技术，推导出该星星的斑点占有率和磁性图。由此产生的亮度图表明HD 106506在所有纬度都显示出光球斑，包括一个主要的极斑。这颗星星的方位角和径向磁场图像已经被导出，并显示出与其他活跃的年轻恒星一致的显著的方位角磁场。一个类似太阳的微分旋转定律被纳入成像过程。使用斯托克斯I信息，赤道自转速率Ωeq为4.54 ± 0.01 rad d-1，光球切变δΩ为0.21+0.02-0.03 rad d-1。这相当于赤道自转周期为1.39 ± 0.01 d，赤道区每隔1.30 +5-3 d与两极重叠一次。利用磁场特征，赤道自转速率Ωeq为4.51 ± 0.01 rad d-1，光球切变δΩ为0.24 ± 0.03 rad d-1。这种差异旋转大约是在太阳上观察到的四倍。
We present the photometry and spectropolarimetry of the pre-main-sequence star HD 106506. A photometric rotational period of ˜1.416 ± 0.133 d has been derived using observations at Mount Kent Observatory (MKO). Spectropolarimetric data obtained with the 3.9-m Anglo-Australian Telescope (AAT) were used to derive spot occupancy and magnetic maps of the star through the technique of Zeeman Doppler imaging (ZDI). The resulting brightness maps indicate that HD 106506 displays photospheric spots at all latitudes including a predominant polar spot. Azimuthal and radial magnetic images of this star have been derived, and a significant azimuthal magnetic field is indicated, in line with other active young stars. A solar-like differential rotation law was incorporated into the imaging process. Using Stokes I information the equatorial rotation rate, Ωeq, was found to be 4.54 ± 0.01 rad d-1, with a photospheric shear δΩ of 0.21+0.02-0.03 rad d-1. This equates to an equatorial rotation period of ˜1.39 ± 0.01 d, with the equatorial region lapping the poles every ˜ 30+5-3 d. Using the magnetic features, the equatorial rotation rate, Ωeq, was found to be 4.51 ± 0.01 rad d-1, with a photospheric shear δΩ of 0.24 ± 0.03 rad d-1. This differential rotation is approximately four times that observed on the Sun.