Energetic radiation from exoplanet hosts: The most detailed study of our nearest host star Proxima Centauri

比邻星b是离地球最近的系外行星，可能适合居住。然而，后者主要依赖于它的主星（一颗活跃的M矮星）的高能辐射的照明。如果没有x射线和紫外线的详细观测，目前还没有一个模型能够足够准确地预测恒星的高能光谱，从而回答可居住性的问题。我们组织了迄今为止最广泛的比邻星x射线到紫外线观测活动，同时以前所未有的细节测量了完整的高能光谱。这包括使用低能量透射光栅光谱仪覆盖175公里的钱德拉x射线，覆盖波长约为2 - 175 a，伴随着哈勃太空望远镜的五个同步轨道紫外线数据，以及ASTROSAT卫星覆盖更高能量的数据，以及支持地面数据。这个项目的目标有两个：首先，我们将为Proxima Cen的不同活动水平创建宽带光谱能量分布，以便详细评估我们最近的系外行星邻居的可居住性；其次，利用目标的邻近性来推进我们对低质量恒星的磁活动的理解，这可能比我们银河系中其他类型的行星宿主数量要多。因此，为了更好地了解孕育生命所必需的天体物理条件，以及这些条件在我们的银河系中有多普遍，也就是说，直接解决了优先计划“探索太阳系外行星的多样性”（SPP 1992）中宣布的主要问题之一。

Proxima Cen b is the nearest exoplanet to Earth - and possibly habitable. The latter, however, depends critically on the illumination by high-energy radiation from its host star, which is an active M dwarf. No models exist that allow a sufficiently accurate prediction of the stellar high-energy spectrum to answer the question of habitability without detailed observations in the X-ray and UV regimes.We have organized the so far most extensive X-ray to UV observing campaign of Proxima Cen to simultaneously measure the complete high-energy spectrum with unprecedented detail. This includes a massive 175 ks of Chandra X-ray coverage using the Low Energy Transmission Grating Spectrometer covering wavelengths from about 2 - 175 A, accompanied by five simultaneous orbits of Hubble Space Telescope UV data as well as coverage at higher energies with the ASTROSAT satellite, plus supporting ground-based data. The goals of this project are twofold: First, we will create broad-band spectral energy distributions for different activity levels of Proxima Cen to enable a detailed assessment of the habitability of our nearest exoplanetary neighbor and, second, to use the proximity of the target to advance our understanding of magnetic activity on low-mass stars, which likely outnumber other types of planet hosts in our Galaxy. Hence, to better understand the astrophysical conditions necessary to harbor life and how common these are in our Milky Way, i.e., directly addresses the one of the main questions posed in the announcement of the Priority Programme "Exploring the Diversity of Extrasolar Planets" (SPP 1992).