the independent pulsations of Jupiter's northern and southen X-ray auroras

Abstract

eneste trabajo se han detectado auroras australes utilizando los datos recabados por los observatorios espaciales XMM-Newton (2007) y Chandra (2016), equipados con espectrómetros y cámaras de fotones que, combinados, facilitaron las imágenes de rayos X de alta resolución.Pero la única herramienta capaz de despejar las dudas de los astrónomos será la sonda Juno de la NASA, una nave no tripulada del tamaño de una cancha de baloncesto impulsada por energía solar y que desde enero de 2016 orbita al planeta gigante para detectar sus auroras y estudiar su formación y su evolución.

Auroral hot spots are observed across the Universe from brown dwarfs1, X-ray pulsars2 and magnetars to planets, and mark the coupling between a surrounding plasma environment and an atmosphere. Within our own solar system, Jupiter possesses the only resolvable example of this large-scale energy transfer. Discovered in 20003, Jupiter s Northern auroral X-ray hot spot occupies the most poleward regions of the planet s aurora and pulses either periodically3,4 or irregularly5,6. X-ray emission line spectra demonstrate that Jupiter s Northern hot spot is produced by relativistic (~MeV/amu) high charge-state oxygen, sulphur and/or carbon ions5 7 undergoing charge exchange. While the Northern soft X-ray aurora has always been observed to be concentrated into a hot spot, 16 years of observations failed to reveal a similar feature in the South3,4,8,9. Here, we report for the first time the existence of a persistent Southern X-ray hot spot. Surprisingly however, this large-scale Southern auroral structure behaves independently of its Northern counterpart. Using XMM-Newton and Chandra X-ray campaigns from May-June 2016 and March 2007, we show that Jupiter s Northern and Southern spots each exhibit different characteristics, including different periodic pulsations and uncorrelated changes in brightness between each spot. These observations challenge currently proposed X-ray generation mechanisms for Jupiter, whereby pulsed magnetic reconnection is invoked to accelerate heavy ions along the Jovian field. They imply instead that highly energetic, non-conjugate magnetospheric processes sometimes drive the polar regions of Jupiter s dayside magnetosphere. Understanding the behaviour and drivers of Jupiter s pair of hot spots is critical to the use of X-rays as diagnostics of the wide-range of rapidly rotating extra-solar objects that exhibit these auroral phenomena