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.

利用视向速度技术或多普勒方法，可以通过测量由轨道行星引力引起的恒星运动引起的多普勒频移来发现太阳系外行星，现有和未来的摄谱仪可以达到0.1-1m的多普勒精度。在这样的测量中，观测到的径向速度散射不再受摄谱仪稳定性或光子噪声的支配，但恒星本身显示出内在的变化。 1-10m/s 的量级，并且不是由行星引起的，造成这种变化的主要机制是磁活动对对流蓝移的影响，因为太阳为了解恒星表面速度场和活动区域的影响提供了宝贵的参考。可以将精确的径向速度观测与空间分辨的太阳表面信息联系起来。我们的项目旨在通过对太阳的高精度观测来提供了解对流蓝移所需的关键信息。我们的设施可以通过结合空间分辨的太阳来提供独特的数据质量。表面观察，太阳作为恒星的观测，以及在宽波长覆盖范围和超高光谱分辨率下前所未有的波长精度我们计划进行两种类型的观测：（1）高保真光谱观测整个太阳盘的太阳强度，即：获得安静区域和活动区域的太阳表面光谱作为恒星边缘角度的函数；以及（2）在每次天气允许的情况下以 3-10 分钟的频率获取太阳作为恒星的光谱。太阳径向速度项目；光谱和径向速度应免费提供给太阳和系外行星社区。