Search for Extra-solar Planet and Dark Stars by Gravitational Microlensing

日本和新西兰的天文学合作称为天体物理学中的微透镜观测，成立于1995年，目的是利用引力微透镜技术搜索MACHO(巨型致密晕天体)形式的暗物质成分以及太阳系外行星。正如广义相对论预测的那样，这项技术利用恒星和其他大质量物体的引力场在太空中有效地形成大透镜。1986年，Bohdan Paczynski指出了微透镜技术的可行性。他建议监测尽可能多的麦哲伦星云和星系凸起中的恒星，以寻找银晕或银盘中的引力透镜。1995年，MOA合作开始使用新西兰约翰山天文台的0.6米望远镜进行观测。2005年，日本在约翰山安装了一台1.8米的望远镜。从那时起，每年都有500多次微透镜事件被发现朝向银河系隆起。还有，…在麦哲伦星云附近发现了更多的事件。气象局发现的事件通过万维网向公众公布，以使其他天文台能够监测选定的事件，特别是那些高倍的事件。这导致了在银盘和星系凸起中发现了16颗绕恒星运行的太阳系外行星。这些行星是在它们的宿主恒星的雪线之外发现的。这是微透镜技术最敏感的区域，也是根据核心吸积理论形成冰巨行星和气巨行星的区域。这些行星上的数据补充了通过径向速度和凌日技术获得的近距离行星上的数据。除了上述发现外，MOA还发现了一类新的太阳系外行星。这些行星并不与恒星联系在一起。它们的质量与木星相似，数量约与银河系中的恒星一样多。最终，澳大利亚农业部的科南大学研究小组完成了1999至2005年间利用约翰山0.6米望远镜对大麦哲伦星云进行的观测分析。大约发现了9,000颗木拉和13,000颗造父变星。这些结果将在其他地方公布。较少

The Japan-NZ astronomy collaboration known as MOA (Microlensing Observations in Astrophysics) was formed in 1995 with the aim of searching for a component of dark matter in the form of MACHOs (Massive Compact Halo Objects) and also for extra-solar planets using the gravitational microlensing technique. This technique uses the gravitational fields of stars and other massive objects to effectively form large lenses in space as predicted by general relativity. The feasibility of the microlensing technique was pointed out by Bohdan Paczynski in 1986. He proposed monitoring as many stars as possible in the Magellanic Clouds and the galactic bulge to find gravitational lenses in the galactic halo or the galactic disc.The MOA collaboration commenced observations in 1995 using a 0.6m telescope at the Mt John observatory in NZ. In 2005 a 1.8m telescope was installed at Mt John by Japan. Since that time more than 500 microlensing events have been found each year towards the galactic bulge. Also, … More events have been found towards the Magellanic Clouds.The events found by MOA were made publicly available via the world wide web to enable other observatories to monitor selected events, in particular those with high magnifications. This resulted in the discovery of 16 extra-solar planets orbiting stars in the galactic disc and the galactic bulge. These planets were found just beyond the snowlines of their host stars. This is the region of maximum sensitivity of the microlensing technique, and it also the region where ice-giant and gas-giant planets form according to the core accretion theory. The data on these planets complements data being obtained on closer-in planets by the radial velocity and transit techniques.In addition to the above discoveries, a new class of extra-solar planets was discovered by MOA. These planets are not bound to stars. They have masses similar to that of Jupiter, and they are approximately as abundant as stars in the galaxy.Finally, the Konan University group of MOA completed the analysis of observations made between 1999 and 2005 towards the Large Magellanic Cloud with the 0.6m telescope at Mt John. Approximately 9,000 Miras and 13,000 Cepheid variable stars were found. Those results will be presented in elsewhere. Less