Steps Towards Achieving Precision Radial Velocities in the NIR: Developing and Testing Techniques with a 1.75um cutoff H2RG array for a Pathfinder Instrument

不久前，我们所知道的唯一的行星就存在于我们的太阳系中。 今天，全世界的行星发现工作已经确定了400多颗行星围绕300多颗恒星运行，其中许多系统与我们的太阳系之间的属性对比正在挑战我们对行星形成和演化的理解。 寻找行星的圣杯一直是确定在主星星的可居住区轨道上运行的近地质量的物体。 这些行星为寻找生命的证据提供了机会，从而更好地了解生命是如何在地球上起源和繁荣的。通过宿主星星的反射运动来探测类地行星质量，需要对中等质量恒星进行极高速度的精确测量--超出了当今最好的仪器的能力--或者研究低质量主序星（即M光谱型）恒星。 因为后者也非常冷，它们很微弱，即使用世界上最大的望远镜进行光学研究，目标列表也很短。 宾夕法尼亚州立大学的Suvrath Mahadevan博士计划升级现有的近红外实验室光谱仪，该光谱仪开创了上述发现中使用的一些技术，并将该光谱仪应用于Hobby-Eberly 9米望远镜，以发现围绕低质量恒星运行的地球质量行星。 在近红外波段，冷星是明亮的，充满了适合径向速度分析的窄吸收特征。 Mahadevan博士正在采取一种合理且具有成本效益的方法，通过采用灵敏度截止检测器阵列来大大降低仪器和法布里-珀罗标准具以及为电信行业开发的气室的冷却要求，以实现精确的波长校准。 很快，这个由科学家和学生组成的小型但经验丰富的小组将带来一种新的仪器，以便在太阳系外行星的研究中利用一个重要的光谱区域。 这项工作的资金由NSF的天文科学部通过其先进技术和仪器计划提供。

It has not been long since the only known planets resided in our solar system. Today, world-wide planet-finding efforts have identified over 400 planets orbiting more than 300 stars, and the contrast in properties between many of these systems and our solar system is challenging our understanding of planetary formation and evolution. The Holy Grail of planet-finding has always been to identify objects with near-Earth masses orbiting in the habitable zone of the host star. These planets offer the opportunity to search for evidence of life and thereby develop a better perspective on how it originated and flourished on Earth.The detection of Earth-like planetary masses through the reflex motion of the host star requires either extremely high velocity precision measurements of moderate mass stars - beyond the capabilities of today's best instruments - or the study of low-mass main-sequence (i.e. M spectral type) stars. Because the latter are also very cool, they are faint and the target list is very short for optical studies even with the world's largest telescopes. Dr. Suvrath Mahadevan at the Penn State University plans to upgrade an existing near-infrared laboratory spectrograph that has pioneered some of the techniques used in the above-mentioned discoveries and to apply that spectrograph at the Hobby-Eberly 9-m telescope toward the discovery of Earth-mass planets orbiting low-mass stars. In the near-IR, cool stars are bright and replete with narrow absorption features suitable for radial velocity analysis. Dr. Mahadevan is taking a reasonable and cost-effective approach by employing a sensitivity-cutoff detector array to greatly reduce the cooling requirements of the instrument and Fabry-Perot etalons and gas cells developed for the telecom industry to accomplish accurate wavelength calibration. Soon, this small but experienced group of scientists and students will bring a new instrument to make use of an important spectral region in the study of extrasolar planets. Funding for this work is being provided by NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.