Understanding Radial Velocity Jitter: Benchmark Observations of the Sun

了解径向速度抖动：太阳的基准观测

• 批准号: 362584317
• 负责人: Professor Dr. Ansgar Reiners
• 金额: --
• 依托单位: Institut für Astrophysik und Geophysik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/362584317?language=en
• 关键词: Understanding; Radial; Velocity; Jitter; Benchmark

With the radial velocity technique, or the Doppler method, extrasolar planets can be discovered from measuring the Doppler shift caused by the motion of a star induced by the gravitational pull of an orbiting planet. Exisiting and future spectrographs reach Doppler precisions on the 0.1-1m/s level. In such measurements, the observed scatter in radial velocity is no longer dominated by spectrograph stability or photon noise, but the stars themselves show intrinsic variations that are on the order of 1-10m/s and not caused by planets. The main mechanism causing this variability is the effect of magnetic activity on convective blueshift. The Sun provides an invaluable reference for understanding the influence of stellar surface velocity fields and active regions because it is possible to relate precision radial velocity observations to spatially resolved solar surface information. Our project aims to provide the key information necessary to understand convective blueshift from very-high-precision observations of the Sun. Our facilities can provide unique data quality by combining spatially resolved solar surface observations, Sun-as-a star observations, and unprecedented wavelength accuracy at wide wavelength coverage and ultra-high spectral resolution. We plan to carry out two types of observations: (1) high-fidelity spectroscopy observing solar intensity across the solar disk, i.e., obtaining spectra of the solar surface in quiet and active regions as a function of stellar limb angle; and (2) spectroscopy of the Sun as a star at 3-10min cadence during every time weather permits. The second part provides regular observations for the Göttingen Solar Radial Velocity Project; the spectra and radial velocities shall be made freely available for solar and exoplanet community.

使用径向速度技术或多普勒方法，可以通过测量由轨道行星的重力拉力引起的恒星运动引起的多普勒移动来发现外星外行星。在0.1-1m/s的水平上，向后放射和未来的光谱仪达到多普勒精确度。在这样的测量值中，观察到的径向速度散射不再由光谱仪的稳定性或光子噪声支配，但是恒星本身显示出固有的变化，而固有的变化为1-10m/s，而不是由行星引起的。引起这种可变性的主要机制是磁活动对对流蓝光的影响。太阳提供了宝贵的参考，以理解恒星表面速度场和活动区域的影响，因为可以将精确的径向速度观察与空间分辨的太阳表面信息相关联。我们的项目旨在提供必要的关键信息，以了解对对流的蓝调，从太阳的非常高精度的观察结果。我们的设施可以通过在宽波长覆盖范围和超高光谱分辨率下结合空间分辨的太阳表面观测，阳光明星观测以及前所未有的波长精度来提供独特的数据质量。我们计划进行两种类型的观察：（1）高保真光谱观测到整个太阳盘上的太阳强度，即，在安静和活跃区域中获得太阳表面的光谱，这是恒星肢体角的函数； （2）在天气允许的情况下，在3-10分钟的节奏中将太阳作为恒星的光谱。第二部分为Göttingen太阳径向速度项目提供了定期观察。光谱和径向速度应免费用于太阳能和系外行星社区。