Reconstructing the solar integrated radial velocity using MDI/SOHO
Reconstructing the solar integrated radial velocity using MDI/SOHO
复制标题
使用 MDI/SOHO 重建太阳积分径向速度
DOI：
10.1051/0004-6361/201014199
复制
发表时间：
2010
影响因子：
6.5
通讯作者：
M. Desort
中科院分区：
文献类型：
--
作者：
N. Meunier;A. Lagrange;M. Desort
上下文用径向速度技术探测系外行星对恒星活动越来越敏感。因此，在研究行星在这些条件下的可探测性时，确定这种活动如何影响径向速度测量至关重要。目标。在以前的工作中，我们模拟了太阳的径向速度上的斑点和plages的影响。我们的目标是比较这个模拟与观测到的径向速度的太阳在同一时期。方法.本文利用MDI/SOHO在一个太阳活动周内获得的多普勒图和磁图，重建了Ni线6768 A °上的太阳积分径向速度。我们还描述了速度和局部磁场之间的关系来解释我们的结果。结果我们得到一个更强的红移的地方，当地的磁场是较大的（作为一个结果，为较大的磁结构）：因此，我们发现一个更高的衰减的对流蓝移的plages比在网络中。我们的研究结果是兼容的衰减约50%时，平均超过plages和网络的蓝移。我们得到了一个综合径向速度的振幅在太阳周期约8 m s-1，与小尺度的变化类似的模拟结果，一旦他们被缩放到Ni线。结论.观测到的太阳积分径向速度与我们以前的模拟结果在30%以内吻合，验证了模拟的正确性。观测到的振幅证实，在磁区对流蓝移衰减的影响将是至关重要的，以检测地球质量的行星周围的太阳系恒星的可居住区。
Context. Searches for exoplanets with radial velocity techniques are increasingly sensitive to stellar activity. It is therefore crucial to characterize how this activity influences radial velocity measurements in their study of the detectability of planets in these conditions. Aims. In a previous work we simulated the impact of spots and plages on the radial velocity of the Sun. Our objective is to compare this simulation with the observed radial velocity of the Sun for the same period. Methods. We use Dopplergrams and magnetograms obtained by MDI/SOHO over one solar cycle to reconstruct the solar integrated radial velocity in the Ni line 6768 A°. We also characterize the relation between the velocity and the local magnetic field to interpret our results. Results. We obtain a stronger redshift in places where the local magnetic field is larger (and as a consequence for larger magnetic structures): hence we find a higher attenuation of the convective blueshift in plages than in the network. Our results are compatible with an attenuation of this blueshift by about 50% when averaged over plages and network. We obtain an integrated radial velocity with an amplitude over the solar cycle of about 8 m s -1 , with small-scale variations similar to the results of the simulation, once they are scaled to the Ni line. Conclusions. The observed solar integrated radial velocity agrees with the result of the simulation made in our previous work within 30%, which validates this simulation. The observed amplitude confirms that the impact of the convective blueshift attenuation in magnetic regions will be critical to detect Earth-mass planets in the habitable zone around solar-like stars.