Imaging Discovery of Other Worlds Around Nearby Stars

成像发现附近恒星周围的其他世界

• 批准号: RGPIN-2014-05022
• 负责人: Marois, Christian
• 金额: $ 2.11万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=658807
• 关键词: Imaging; Discovery; Other; Worlds; Around

Over the past 20 years, the number of known exoplanets has grown exponentially to close to 1,000. The vast majority of these exoplanets orbit very close to their primary star (the so called hot Jupiters), but a few of them are low mass Earth-size planets in orbit around lower mass stars, possibly in the systems' habitable zones where liquid water, and life-as-we-know-it, could exist. While those discoveries are very exciting, what we know about these exoplanets is still very limited, as the vast majority of them have been discovered using indirect techniques. Detailed photometry and spectroscopy are needed to properly characterize planets, but this detailed analysis has only been conducted on a few to date due to limitations of existing instrumentation. **The direct exoplanet imaging technique remains the simplest way to characterize an exoplanet. When the light of a planet is directly detected, a spectrograph can be used to: study the planet atmospheric composition; estimate its atmospheric temperature/luminosity; evaluate its surface gravity; study the effect of clouds and, for rocky planets; find signs of life. Direct exoplanet imaging is a challenging endeavor due to the small star/planet angular separation and large luminosity ratio between the host star and the planet, from 100,000 times fainter for a warm young Jupiter-like planet to tens of billion of times fainter for an Earth-like planet. **After 10 years of development, a first wave of dedicated, facility-class, highly-optimized exoplanet imaging instruments is being shipped to observatories. My team (also the building team of the Gemini Planet Imager, GPI) has secured 900h of observing time on GPI for a nearby 600 stars campaign to find and characterize approximately 50 new warm Jupiter-like planets (10 times more than currently imaged). GPI will achieve 100x deeper contrast than existing instruments by the use of a starlight blocking mask and precise wavefront control, allowing a unique view of young and nearby planetary systems.**This NSERC Discovery grant will enable me to fund two graduate students that will join the GPI team for this exciting adventure. The students may acquire, reduce and analyze GPI data, help organize the campaign and/or perform detailed analyses, such as orbit fitting, stability studies for multi-planet systems and search for photometric/spectroscopic time variations generated by changing cloud cover. Part of their time will be allocated to further develop the image subtraction algorithms and study possible upgrades to the instrument. **The students will also participate in the design process of their future exoplanet imaging tools, by performing numerical simulations for the planned Thirty Meter Telescope (TMT) and a space exoplanet imaging telescope (MAPLE). The TMT is part of the next generation of extremely large telescopes currently in the designing/building stage, representing a 3x increase in aperture to current facilities. The TMT will achieve unparalleled resolution, allowing to directly image Jovian planets at solar system scale (< 10 astronomical units (AU), i.e. 10x the Earth-Sun separation). With optimized instruments that the students will help conceive, it may even be possible to directly image Earth-like planets around the nearest low mass stars. The project MAPLE is a new Canadian-led space telescope concept that I am leading. The students will analyze the performance of this 50 cm diameter visible-band space telescope to directly image, around the nearest stars, the reflected light of super-Earth/ice giant planets in orbit around the nearest stars. **The expertise gained by studying those concepts will be applicable to future observatories that will one day take a picture of an Earth-like planet.

过去 20 年来，已知系外行星的数量呈指数级增长，已接近 1,000 颗。这些系外行星中的绝大多数的轨道非常靠近它们的主恒星（所谓的热木星），但其中一些是低质量的地球大小的行星，围绕较低质量的恒星运行，可能位于该系统的宜居带，那里可能存在液态水和我们所知的生命。虽然这些发现非常令人兴奋，但我们对这些系外行星的了解仍然非常有限，因为其中绝大多数是使用间接技术发现的。需要详细的光度测量和光谱学来正确表征行星，但由于现有仪器的限制，迄今为止仅对少数行星进行了详细的分析。 **直接系外行星成像技术仍然是表征系外行星的最简单方法。当直接探测到行星的光时，光谱仪可用于： 研究行星大气成分；估计其大气温度/光度；评估其表面重力；研究云和岩石行星的影响；寻找生命迹象。直接系外行星成像是一项具有挑战性的工作，因为恒星/行星角距较小，主恒星与行星之间的光度比较大，从温暖的年轻类木星行星的亮度比暗10万倍到类地行星的亮度比暗数百亿倍。 **经过 10 年的发展，第一批专用、设施级、高度优化的系外行星成像仪器正在运往天文台。我的团队（也是双子座行星成像仪 (GPI) 的构建团队）已在 GPI 上确保了 900 小时的观测时间，用于附近 600 颗恒星的活动，以寻找和描述大约 50 颗新的温暖类木星行星（比当前成像的多 10 倍）。通过使用星光阻挡掩模和精确的波前控制，GPI 将实现比现有仪器深 100 倍的对比度，从而获得年轻和附近行星系统的独特视图。**这笔 NSERC 发现补助金将使我能够资助两名研究生，他们将加入 GPI 团队进行这次激动人心的冒险。学生可以获取、减少和分析 GPI 数据，帮助组织活动和/或执行详细分析，例如轨道拟合、多行星系统的稳定性研究以及搜索因云层变化而产生的光度/光谱时间变化。他们的部分时间将用于进一步开发图像减影算法并研究仪器的可能升级。 **学生还将通过对计划中的三十米望远镜（TMT）和太空系外行星成像望远镜（MAPLE）进行数值模拟来参与未来系外行星成像工具的设计过程。 TMT 是目前处于设计/建造阶段的下一代超大望远镜的一部分，其孔径比现有设施增加了 3 倍。 TMT 将实现无与伦比的分辨率，从而能够直接对太阳系尺度的木星行星进行成像（< 10 个天文单位 (AU)，即地球与太阳距离的 10 倍）。借助学生们帮助构想的优化仪器，甚至可以直接对最近的低质量恒星周围的类地行星进行成像。 MAPLE 项目是我领导的加拿大主导的新太空望远镜概念。学生们将分析这台直径 50 厘米的可见光波段太空望远镜的性能，以直接对最近恒星周围的超级地球/冰巨行星在最近恒星轨道上的反射光进行成像。 **通过研究这些概念获得的专业知识将适用于未来的天文台，有一天将拍摄一颗类地行星的照片。