Jupiter's X-Ray and UV Dark Polar Region
Jackman, C. M.; Johnson, R. E.; Branduardi-Raymont, G.; Bonfond, B.; Nichols, J. D.; Ray, L. C.; Grodent, D.; Yao, Z. H.; Guo, R. L.; Gladstone, G. R.; Dunn, W. R.; May, D.; Wibisono, A. D.; Kraft, R. P.; Weigt, D. M.; Fleming, D.; Feigelman, K.; Sipos, B.; McEntee, S.
United Kingdom, Ireland, Belgium, China, Austria, United States
Abstract
We present 14 simultaneous Chandra X-ray Observatory (CXO)-Hubble Space Telescope (HST) observations of Jupiter's Northern X-ray and ultraviolet (UV) aurorae from 2016 to 2019. Despite the variety of dynamic UV and X-ray auroral structures, one region is conspicuous by its persistent absence of emission: the dark polar region (DPR). Previous HST observations have shown that very little UV emission is produced by the DPR. We find that the DPR also produces very few X-ray photons. For all 14 observations, the low level of X-ray emission from the DPR is consistent (within 2-standard deviations) with scattered solar emission and/or photons spread by Chandra's Point Spread Function from known X-ray-bright regions. We therefore conclude that for these 14 observations the DPR produced no statistically significant detectable X-ray signature.