Lab Astro for Studies of the Synthesis of Fe-group Elements

该奖项将为威斯康星州原子跃迁概率(WATP)计划提供持续支持。该项目包括完成非常精确和准确的钛的跃迁概率测量。这些测量将包括TiII中具有低激发势的非常重要的弱线。这些线采样了恒星光球层中的大部分钛。类似的测量随后将扩展到钴、镍和钒。发射分支分数将使用傅里叶变换光谱仪的可用光谱和最近开发的3m焦距真空梯形光谱仪的新数据来测量。辐射寿命测量将使用WATP计划的时间分辨激光诱导荧光实验在原子/离子束上进行。这些铁组测量的系统不确定度将在高置信度下为5%或更低。合作的天文学家将利用这一实验室数据来确定(旧的)贫金属星中高度可靠的相对铁族丰度。研究工作将包括对本科生和研究生的培训。预计该项目将有助于解释未来对银河系郊区贫金属星的大规模光谱调查。

This award will provide continuing support for the Wisconsin Atomic Transition Probability (WATP) program. The project includes the completion of very precise and accurate transition probability measurements of Titanium. These measurements will include the very important weak lines with low excitation potential in Ti II. Such lines sample the majority of the titanium in the photospheres of stars. Similar measurements will subsequently be extended to cobalt, nickel, and vanadium. Emission branching fractions will be measured using available spectra from a Fourier transform spectrometer and new data from a recently developed 3 m focal length vacuum echelle spectrograph. Radiative lifetime measurements will be performed on atom/ion beams using a WATP program time-resolved laser induced fluorescence experiment. Systematic uncertainties on these iron-group measurements will be 5% or less with high confidence. Collaborating astronomers will apply this lab data to determine highly reliable relative iron-group abundances in (old) metal-poor stars.The research effort will include the training of undergraduate and graduate students. The project is expected to aid in the interpretation of future large-scale spectroscopic surveys of metal-poor stars in the outskirts of the Milky Way.