The PLATO 2.0 mission
The PLATO 2.0 mission
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PLATO 2 0 任务
DOI：
10.1007/s10686-014-9383-4
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发表时间：
2014
影响因子：
3
通讯作者：
Catala
中科院分区：
文献类型：
--
作者：
Catala
柏拉图2.0最近被选为欧空局M3发射机会(2022/24)。它以统计数字提供了准确的关键行星参数(半径、质量、密度和年龄)，解决了诸如：行星系统是如何形成和演化的基本问题？有没有其他系统拥有像我们这样的行星，包括潜在的宜居行星？柏拉图2.0仪器由34个小口径望远镜组成(32个具有25个S读数节拍，2个具有2.5个S节拍)，提供了宽视场(2232°2)和大的光度等范围(4-16 MAG)。它聚焦于大视场中明亮的(4-11 MAG)恒星，通过光度凌日探测和描述小至地球大小的行星，然后通过地面径向速度后续测量确定行星的质量。将对这些明亮的恒星进行星震学研究，以获得高精度的恒星参数，包括质量和年龄。明亮的目标和星震学的结合导致了大体积行星参数的高精度：行星半径、质量和年龄分别为2%、4%-10%和10%。计划中的基线观测战略包括两个长点(2-3年)，以探测和大量描述进入类太阳恒星宜居带(HZ)的行星，以及一个额外的步幅和凝视阶段，总共覆盖大约50%的天空。柏拉图2.0将观测多达100万颗恒星，并探测和表征数百颗小行星，以及海王星上数以千计的行星，从海王星到HZ的气体巨型区域。因此，它将提供第一个具有准确半径、质量、平均密度和年龄的大型特征行星目录。该目录将包括中等轨道距离的类地行星，这些行星的表面温度适中。这一参数范围与大量表征行星的统计数字的覆盖范围是柏拉图2.0所独有的。柏拉图2.0星表允许我们例如：-完成我们对低质量天体的行星多样性的知识，-将行星平均密度-轨道距离分布与行星形成理论的预测相关联，-约束行星迁移和散射对多个系统结构的影响，以及-指定行星和系统参数如何随宿主恒星的特征而变化，例如类型、金属丰度和年龄。该星表将使我们能够研究处于不同演化阶段的行星和行星系统。它将进一步提供小质量、低质量行星的普查。这将有助于识别那些保留了原始氢气大气的天体，以及处于这种低质量、低密度范围内的行星的典型特征。柏拉图2.0探测到的行星将围绕明亮的恒星运行，其中许多行星将成为未来大气光谱探测其大气层的目标。此外，该飞行任务有可能探测系外行星、行星环、双星和特洛伊行星。柏拉图2.0可能实现的行星科学，通过星震学对恒星和银河系科学的影响，以及各种变星的光曲线，以及对不同年龄的星团的观察，来补充这一点。这将使我们能够改进恒星模型并研究恒星活动。来自红巨星的大量众所周知的年龄将探索我们银河系的结构和演化。恒星演化不同阶段的明亮恒星的恒星地震年龄可以校准恒星年龄-旋转关系。与欧空局盖亚任务的结果一起，柏拉图2.0的结果将为行星、恒星和银河系科学提供巨大的遗产。
PLATO 2.0 has recently been selected for ESA’s M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, including potentially habitable planets? The PLATO 2.0 instrument consists of 34 small aperture telescopes (32 with 25 s readout cadence and 2 with 2.5 s candence) providing a wide field-of-view (2232 deg 2) and a large photometric magnitude range (4–16 mag). It focusses on bright (4–11 mag) stars in wide fields to detect and characterize planets down to Earth-size by photometric transits, whose masses can then be determined by ground-based radial-velocity follow-up measurements. Asteroseismology will be performed for these bright stars to obtain highly accurate stellar parameters, including masses and ages. The combination of bright targets and asteroseismology results in high accuracy for the bulk planet parameters: 2 %, 4–10 % and 10 % for planet radii, masses and ages, respectively. The planned baseline observing strategy includes two long pointings (2–3 years) to detect and bulk characterize planets reaching into the habitable zone (HZ) of solar-like stars and an additional step-and-stare phase to cover in total about 50 % of the sky. PLATO 2.0 will observe up to 1,000,000 stars and detect and characterize hundreds of small planets, and thousands of planets in the Neptune to gas giant regime out to the HZ. It will therefore provide the first large-scale catalogue of bulk characterized planets with accurate radii, masses, mean densities and ages. This catalogue will include terrestrial planets at intermediate orbital distances, where surface temperatures are moderate. Coverage of this parameter range with statistical numbers of bulk characterized planets is unique to PLATO 2.0. The PLATO 2.0 catalogue allows us to e.g.: - complete our knowledge of planet diversity for low-mass objects, - correlate the planet mean density-orbital distance distribution with predictions from planet formation theories,- constrain the influence of planet migration and scattering on the architecture of multiple systems, and - specify how planet and system parameters change with host star characteristics, such as type, metallicity and age. The catalogue will allow us to study planets and planetary systems at different evolutionary phases. It will further provide a census for small, low-mass planets. This will serve to identify objects which retained their primordial hydrogen atmosphere and in general the typical characteristics of planets in such low-mass, low-density range. Planets detected by PLATO 2.0 will orbit bright stars and many of them will be targets for future atmosphere spectroscopy exploring their atmosphere. Furthermore, the mission has the potential to detect exomoons, planetary rings, binary and Trojan planets. The planetary science possible with PLATO 2.0 is complemented by its impact on stellar and galactic science via asteroseismology as well as light curves of all kinds of variable stars, together with observations of stellar clusters of different ages. This will allow us to improve stellar models and study stellar activity. A large number of well-known ages from red giant stars will probe the structure and evolution of our Galaxy. Asteroseismic ages of bright stars for different phases of stellar evolution allow calibrating stellar age-rotation relationships. Together with the results of ESA’s Gaia mission, the results of PLATO 2.0 will provide a huge legacy to planetary, stellar and galactic science.