标题： 土星、天王星和海王星的X射线发射搜索 显示英文标题

标题： A Search for X-ray emission from Saturn, Uranus and Neptune

摘要： 我们利用ROSAT PSPC对土星、天王星和海王星的X射线观测进行了分析，并与木星的X射线观测进行了比较。首次发现了土星的边际X射线探测，并获得了天王星和海王星的95%置信度上限。这些上限表明，排除了类似木星的X射线亮度，但假设土星式的固有X射线亮度则是一致的。因此，不能排除所有跨木行星具有相似的X射线产生机制，而从土星观测到的光谱形状和总亮度与由电子沉降引起的厚靶韧致辐射一致，正如地球极光发射中所发生的那样。 显示英文摘要

摘要： We present an analysis of X-ray observations of the trans-Jovian planets Saturn, Uranus and Neptune with the ROSAT PSPC in comparison with X-ray observations of Jupiter. For the first time a marginal X-ray detection of Saturn was found and 95% confidence upper limits for Uranus and Neptune were obtained. These upper limits show that Jupiter-like X-ray luminosities can be excluded for all three planets, while they are consistent assuming intrinsic Saturn-like X-ray luminosities. Similar X-ray production mechanisms on all trans-Jovian planets can therefore not be ruled out, and spectral shape and total luminosity observed from Saturn are consistent with thick-target bremsstrahlung caused by electron precipitation as occurring in auroral emission from the Earth.