A New High Resolution Charge-Coupled Device Spectrometer for McDonald Observatory

德克萨斯大学麦克唐纳天文台将建造一个高- 新型设计的高分辨率摄谱仪， 中阶梯光栅和棱镜交叉色散。 光谱将是 投影到最大的电荷耦合器件（CCD）图像上 探测器--新的泰克TK 2048 M。 55毫米 方形固态硅成像探测器将产生超过4 百万像素 通过这种组合， 一个天体的整个光谱 CCD的紫外截止和近红外截止 将以高分辨率同时获得灵敏度。 一 1-小时曝光将获得V星等11的恒星光谱 具有信噪比100，而可以获得有用的光谱， 3小时内达到15级 新仪器的主要动机是它能够 快速、完整地收集测定CNO所需的光谱， （碳，氮和氧）丰度在星团恒星和 在古老的贫金属矮星、恒星中的镁同位素丰度 比目前这些研究的极限还要微弱。 的 寻找附近明亮恒星周围的行星将依赖于 通过大的统计数据实现高径向速度精度 错误测量的谱线轮廓的数量， 确定母星星的小周期运动， 行星的轨道运动

The University of Texas McDonald Observatory will build a high- resolution spectrograph of novel design incorporating a large echelle grating and prism cross dispersion. Spectra will be projected onto the largest Charge Coupled Device (CCD) image detector available -- the new Tektronix TK2048M. This 55-mm square solid state silicon image detector will produce over 4 million picture elements per exposure. With this combination the entire spectrum of an astronomical object between the atmospheric ultraviolet (UV) cutoff and the near-infrared (IR) limit of CCD sensitivity will be acquired simultaneously at high resolution. A 1-hour exposure will obtain spectra of stars at V magnitude 11 with signal-to-noise 100, while useful spectra can be obtained to magnitude 15 in 3 hours. Major motivations for the new instrumentation are its ability to gather quickly and completely spectra needed to determine CNO, (Carbon, Nitrogen, and Oxygen) abundances in cluster stars and magnesium (Mg) isotopic abundances in old metal-poor dwarfs, stars that are fainter than current limits for these studies. The search for planets around nearby bright stars will rely on the high radial velocity precision enabled by the statistics of large numbers of simultaneously-measured spectral line profiles to determine small periodic motions in the parent star induced by orbital motion of the planet.