In the version of this article initially published, the current reference 27 was omitted in the Methods, “X-ray observations and data reduction” paragraph. Further, the title and captions for Extended Data Figs. 1 and 2 were swapped. The errors have been corrected in the HTML and PDF versions of the article.

27. Giorgini, J. D. et al. JPL’s On-Line Solar System Data Service. AAS 28, 1158 (1996).