结合注意力机制的恒星视向速度计算方法  

A Computing Method of Stellar Radial Velocity by Integrating Attention Mechanism

作　　者：石泽华 康志伟 刘劲[2] SHI Ze-hua;KANG Zhi-wei;LIU Jin(College of Computer Science and Electronic Engineering,Hunan University,Changsha 410082,China;College of Information Science and Engineering,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]湖南大学信息科学与工程学院,湖南长沙410082 [2]武汉科技大学信息科学与工程学院,湖北武汉430081

出　　处：《光谱学与光谱分析》2024年第9期2531-2537,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(61772187,61873196)资助。

摘　　要：视向速度法是一种根据目标恒星的视向速度变化来推断系外行星是否存在的有效方法,它对系外行星探测有重要作用。由于恒星活动、观测光谱与模板光谱的差异以及其他因素导致的光谱噪声,采用交叉相关算法计算恒星的视向速度会存在一定误差。提出了一种结合注意力机制的恒星视向速度计算方法,该方法对恒星光谱数据进行处理以去除光谱中的噪声,根据恒星视向速度变化的周期性计算恒星的视向速度。首先,采用高斯过程回归算法建立光谱模型,减少噪声的影响,得到更加准确的光谱数据。子集近似法被应用到光谱建模的过程中以减少计算量。然后,结合注意力机制的思想,为光谱中的吸收线赋予不同的权重,计算不同光谱间的视向速度差。最后,根据各视向速度差之间的关系,计算出恒星的视向速度。本文通过仿真实验分析了信噪比和恒星光谱数量对视向速度计算误差的影响。实验结果表明,相较于交叉相关算法,当信噪比较低时,结合注意力机制的恒星视向速度计算方法能有效减小视向速度的计算误差,通过增加恒星光谱数量能在一定程度上提高视向速度的计算准确度。对HD85512的光谱数据进行了分析。与其他算法相比,本文提出的算法减小了视向速度的计算误差,较大地提高了计算精度。The radial velocity method is quite effective in discovering and characterizing exoplanets based on the radial velocity change of the target stellar.It plays an important role in the detection of exoplanets.Owing to stellar activities,the differences between spectra and template,and the noise in spectra for other reasons,radial velocities calculated by the cross-correlation function algorithm may have some errors.This paper proposes a method of measuring stellar radial velocities,and an attention mechanism is integrated.Observed spectra are processed to remove noise from the spectra,and radial velocity is calculated based on the periodicity of stellar radial velocity.First,Gaussian Process Regression is used to establish spectral models,which helps reduce the influence of noise and get more precise spectra.A subset of data is used to reduce the computation cost.Then,based on the idea of attention mechanism,different weight is assigned for the absorption lines to figure out differential radial velocities between spectra.Finally,radial velocities of stellar are obtained using the relationship of differential radial velocities.This paper analyzes the effect of the signal-to-noise ratio and the number of spectra on the mean error of radial velocities.The experimental results show that compared to the cross-correlation function algorithm,the stellar radial velocity calculation method combined with the attention mechanism can effectively reduce the error of radial velocities when the signal-to-noise ratio is low.Increasing the number of spectra helps improve the accuracy of radial velocities to some degree.Finally,The spectra of HD85512are analyzed.Compared with other algorithms,the algorithm proposed in this paper reduces the error of radial velocities and greatly improves the accuracy.

关 键 词：恒星光谱 视向速度 高斯过程回归 注意力机制 

分 类 号：P144.5[天文地球—天体物理]