First observation of Jupiter by XMM-Newton

¹ Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK e-mail: gbr@mssl.ucl.ac.uk
² NASA Marshall Space Flight Center, SD50, Huntsville AL 35812, USA
³ Southwest Research Institute, San Antonio, Texas 78228, USA
⁴ XMM-Newton SOC, Apartado 50727, Villafranca, 28080 Madrid, Spain
⁵ University of Michigan, Space Research Building, 2455 Hayward, Ann Arbor, Michigan 48109, USA

Received: 22 April 2004
Accepted: 23 May 2004

Abstract

We present the first X-ray observation of Jupiter by XMM-Newton. Images taken with the EPIC cameras show prominent emission, essentially all confined to the 0.2-2.0 keV band, from the planet's auroral spots; their spectra can be modelled with a combination of unresolved emission lines of highly ionised oxygen (OVII and OVIII), and a pseudo-continuum which may also be due to the superposition of many weak lines. A 2.8σ enhancement in the RGS spectrum at 21-22 Å (~0.57 keV) is consistent with an OVII identification. Our spectral analysis supports the hypothesis that Jupiter's auroral emissions originate from the capture and acceleration of solar wind ions in the planet's magnetosphere, followed by X-ray production by charge exchange. The X-ray flux of the North spot is modulated at Jupiter's rotation period. We do not detect evidence for the ~45 min X-ray oscillations observed by Chandra more than two years earlier. Emission from the equatorial regions of the planet's disk is also observed. Its spectrum is consistent with that of scattered solar X-rays.