标题： 径向速度变化：行星还是脉动？ 显示英文标题

标题： Radial Velocity Variations in K Giants: Planets or Pulsations?

摘要： 对K巨星的视向速度观测揭示了一些恒星存在周期性变化。 这些周期范围从大约180到1000天以上，速度振幅范围从约50 m/s到500 m/s。 除了Iota Draconis（Frink等人，2002年）外，所有变化几乎都是正弦波。 零轨道偏心率的伴星以及脉动可能是导致这些视向速度变化的原因。 为了揭示是哪种机制起作用，拍摄了额外的高分辨率光谱。 目前还不能从这项工作中得出结论，但至少对于某些恒星，脉动似乎是最佳解释。 进行了一项理论研究，以探讨什么样的脉动可能引起这些长周期的视向速度变化。 显示英文摘要

摘要： Radial velocity observations of K giants have revealed periodic variations for some of the stars. The periods range from approximately 180 to 1000 or more days with velocity amplitudes ranging from approximately 50 m/s to 500 m/s. Except for Iota Draconis (Frink et al. (2002)), all variations are nearly sinusoidal. Companions with zero orbital eccentricity as well as pulsations may cause these radial velocity variations. Additional high resolution spectra were taken in order to reveal which of these mechanisms is at work. No conclusions can be drawn from this work yet, although it seems likely that at least for some stars pulsations are the best explanation. A theoretical study is performed to investigate what kind of pulsations could cause these long period radial velocity variations.