RUI: Search for Substellar Companions

马西博士将利用主恒星的反射速度来寻找恒星的质量极低的黑暗伴星。他将使用一种新的测量技术，该技术将显著提高径向速度的精度，并允许在轨道周期内检测质量低于3倍木星质量的恒星伴星。他希望进一步改进分析，以便能够探测到质量更低的伴星。天文学中长期存在的一个困难是确定亚恒星物体的性质，即质量太小而无法支持稳定的核氢燃烧的“恒星”。这些天体涉及天文学的几个不同的子领域，例如：(1)在我们银河系的圆盘和其他星系的光晕中识别看不见的物质；(2)对低质量恒星形成和原恒星破碎的认识；(3)确定有伴星环绕的低质量恒星的质量，以便更好地确定恒星主序低质量端的恒星质量函数和双星出现的频率。虽然有几个有趣的候选者，但目前还没有确认太阳系外的真正的亚恒星物体。马西博士的目标是利用一种改进的观测技术，探测质量小于木星1倍的恒星的次恒星伴星。该奖项是在美国国家科学基金会本科院校研究（RUI）项目的支持下颁发的。

Dr. Marcy will search for extremely low mass, dark companions to stars by using the reflex velocity of the host star. He will use a new measurement technique which should significantly improve the precision of radial velocities and permit the detection of stellar companions with masses as low 3 Jupiter-masses, for orbital periods up to the duration of the observations. He hopes to further improve the analysis so that companions of even lower mass will be detectable. A long standing difficulty in astronomy as been the determination of the properties of substellar objects, "stars" of too little mass to support stable nuclear hydrogen burning. Such objects bear on several diverse subfields of astronomy, such as: (1) the identification of unseen matter both in the disk of our Galaxy and in halos of other galaxies; (2) the understanding of star formation and protostellar fragmentation at low stellar masses; and (3) the determination of masses of low mass stars orbited by substellar companions to better determine the stellar mass function and the frequency of binary stars at the low mass end of the main sequence of stars. Although there are several interesting candidates, there are currently no confirmed bona fide substellar objects known outside our Solar System. Dr. Marcy's objective is to use an improved observational technique that will permit detection of substellar companions of stars down to masses of about 1 Jupiter- mass. This award is made under the auspices of the NSF Research in Undergraduate Institutions (RUI) program.