A Search for Extra-Solar-System Planets Using Multi-Color Microlensing Detection Techniques

DePoy博士和他的联合首席研究员Andrew P. Gould博士将进行为期3年的太阳系外行星搜索。搜索将基于多色微透镜探测技术（见下文）。要使用的仪器是俄亥俄州立红外成像仪和光谱仪，它是由以前的NSF拨款建造的（AST 90-16112给J. A. Frogel和AST 92-18449给D. L. DePoy博士）。观测将在Cerro Tololo Inter-American天文台（CTIO） 1米望远镜上进行。“微透镜”指的是当背景恒星被较远的恒星遮蔽（或接近遮蔽）时，它被放大的现象。对于太阳质量的恒星，微透镜光曲线的时间尺度大约是两个月。如果附近的恒星有行星，它们的存在可以通过搜索标准微透镜光曲线的偏差来推断。预计这些偏差将在不到一天的时间内暴露出来。微透镜搜索需要对数百万颗恒星进行夜间光度测量和复杂的数据处理。研究人员将依赖于已经在进行微透镜调查的团队的通知，这些团队试图探测宇宙中的暗物质。德波伊博士和他的同事与三个这样的微透镜/暗物质团队有着密切的联系。一旦确定了目标，研究人员将对其进行监测，并寻找与标准微透镜光曲线的偏差。同时，它们将以两个间隔很宽的波长拍摄目标的图像。这些额外的成像信息将使他们能够约束恒星和行星的质量，并确定它们的物理距离。他们估计，如果所有的恒星都有与我们类似的行星系统，他们可能会在两年的监测期间发现10-20颗木星质量的行星。探测到质量和地球一样低的行星的可能性很小。如果结果为零，研究人员就可以确定行星的存在。＊＊＊

95-30619 DePoy Dr. DePoy and his Co-Principal Investigator, Dr. Andrew P. Gould, will carry out a 3-year search for extra-solar planets. The search will be based on a multi-color microlensing detection technique (see below). The instrument to be used is the Ohio State Infrared Imager and Spectrometer, which was built with previous NSF grants (AST 90-16112 to J. A. Frogel and AST 92-18449 to Dr. D. L. DePoy). Observations will be carried out at the Cerro Tololo Inter-American (CTIO) Observatory 1-meter telescope. "Microlensing" refers to the magnification of a background star when it is occulted (or nearly occulted) by a less distant star. For solar-mass stars, microlensing light curves have time scales of about two months. If the nearby star has planets, their presence can be inferred by searching for deviations from the standard microlensing light curve. Such deviations are expected to reveal themselves in less than a day. Microlensing searches require nightly photometry of millions of stars and sophisticated data processing. The investigators will rely on notification from teams that are already carrying out microlensing surveys in the attempt to detect dark matter in the universe. Dr. Depoy and his coworkers have close ties to three such microlensing/dark matter teams. Once a target has been identified, the investigators will monitor it and look for deviations from the standard microlensing light curve. Simultaneously, they will take images of the target in two widely spaced wavelengths. This additional imaging information will allow them to constrain the masses of both the star and planet, and to determine their physical separation. They estimate that they may be able to detect 10-20 Jupiter-mass planets during two years of monitoring if all stars have planetary systems similar to ours. There is a small probability of detecting planets with masses as low as the earth's. A null-result would allow the investigators to const rain the existence of planets. ***