Design Study: Mission to Alpha Centauri

在半人马座阿尔法星系中，使用目前2米/S的光谱多普勒精度和极端节奏，即每晚数百次观测，应该可以探测到质量和轨道周期类似于金星、地球和火星的行星系统。这种观测节奏可以达到每秒几厘米的有效精度，这已经在星震学项目中得到了证明，这对这个目的来说已经足够了。这里，旧金山州立大学的Debra Fischer博士、华盛顿卡内基研究所的R.Paul Butler博士和加州大学圣克鲁斯分校的Gregory Laughlin博士将进行一项设计研究，将最近退役的Blanco光谱仪与塞罗托洛美洲天文台的1.5米SMARTS联盟望远镜进行光纤耦合。这项设计研究将确定开始进行这样一项长期、高节奏的多普勒探测的可行性，以寻找太阳系中四颗岩石行星的类似物，这些行星围绕着最近的五颗恒星：半人马座阿尔法星A和B、人马座Tau Ceti、GJ780和海蛇座Beta。这项计划有可能促进地面多普勒测量战略的巨大变化，这将有助于为未来的科学资金和资源分配提供信息。这些观测还将通过星震学提供前所未有的关于恒星大气的信息，对G0型恒星Alpha Centauri A和K0型恒星Alpha Centauri B进行差异化比较。这项工作由天文科学部恒星天文学和天体物理学项目资助，作为探索研究的小额赠款。

A system of planets with masses and orbital periods similar to Venus, Earth and Mars should be detectable in the Alpha Centauri system using the current spectroscopic Doppler precision of 2 m/s combined with extreme cadence, i.e., hundreds of observations per night, every possible night. This observing cadence could achieve an effective (phase-binned) precision of a few centimeters per second, already demonstrated in asteroseismology programs, which would be sufficient for this purpose.Here, Drs. Debra Fischer (San Francisco State University), R. Paul Butler (Carnegie Institute of Washington), and Gregory Laughlin (University of California - Santa Cruz) will conduct a design study to fiber-couple the recently decommissioned Blanco spectrometer to the 1.5-m SMARTS consortium telescope at the Cerro Tololo Inter-American Observatory. This design study will determine the feasibility of beginning such a long term, high-cadence Doppler survey to search for analogs of the four rocky planets in our solar system around five of the nearest stars: Alpha Centauri A and B, Tau Ceti, GJ780 and Beta Hydri. This program has the potential to catalyze dramatic changes in the strategy for ground-based Doppler surveys that will help inform future allocation of science funding and resources. The observations will also provide unprecedented information about stellar atmospheres via asteroseismology, differentially comparing the G0-type star, Alpha Centauri A, and the K0-type star, Alpha Centauri B. This work is funded from the Stellar Astronomy and Astrophysics program of the Division of Astronomical Sciences, as a Small Grant for Exploratory Research.