中国SONG项目高分辨光谱仪与高精度恒星震动视向速度测量

摘要

中国SONG项目(Stellar Observations Network Group)是中国天文界参与的一个国际合作的天文学研究计划.其核心是利用高分辩光谱仪获取恒星的时序光谱.光谱仪的分辨率根据科学目标的要求,用不同的狭缝宽度实现 R=60000~120000.利用碘蒸汽发射线定标的方法,实现高达1 m·s-1的视向速度测量精度,以此测量恒星表面由于恒星震动产生的多普勒运动,并实现项目的科学目标.SONG光谱仪是项目的核心设备,将介绍光谱仪的性能和天体物理应用的参数,并给出实际测量结果.作为一个测量恒星表面多普勒运动时序数据的仪器,整个系统的长期稳定性是项目取得成功的关键,在此也将展示仪器稳定性方面的工作.%SONG(Stellar Observations Network Group)is an international collaboration project involving many countries. Chinese stellar physics community is participating the project as a national member,contributing a full set of instruments and a site.The key instrument is a high resolution spectrograph which,when adopting iodine cell for wave length calibration,can deliver radial velocity measurements at an accuracy of 1 m·s-1.Such a high accuracy together with the long term stability is the keys to the science goals of SONG,one of which is to study the internal structure of stars directly using the technique of Astero-seismology.In this paper,we are going to present the design,parameters and performance of the spectrograph by using spectra taken during the commissioning of the system.As long term thermo-mechanic stability of the system is extremely important for the science goals,we will also describe the laboratory environments to realize such a condition.