This composite image shows Jupiter and its aurorae during a solar coronal mass ejections’s arrival at Jupiter on 2 October 2011. In the image, X-ray data from Chandra (purple) have been overlaid on an optical image from the NASA/ESA Hubble Space Telescope. Image credit: X-ray: NASA/CXC/UCL/W.Dunn et al, Optical: NASA/STScI.Solar storms are triggering X-ray aurorae on Jupiter that are about eight times brighter than normal over a large area of the planet and hundreds of times more energetic than Earth’s “northern lights,” according to a new study using data from NASA’s Chandra X-ray Observatory. This result is the first time that Jupiter’s aurorae have been studied in X-ray light when a giant solar storm arrived at the planet.
The Sun constantly ejects streams of particles into space in the solar wind. Sometimes, giant storms, known as coronal mass ejections (CMEs), erupt and the winds become much stronger. These events compress Jupiter’s magnetosphere, the region of space controlled by Jupiter’s magnetic field, shifting its boundary with the solar wind inward by more than a million miles. This new study found that the interaction at the boundary triggers the X-rays in Jupiter’s aurorae, which cover an area bigger than the surface of the Earth.This composite image shows Jupiter and its aurorae on 4 October 2011, two days after a solar coronal mass ejection had subsided. In the image, X-ray data from Chandra (purple) have been overlaid on an optical image from the NASA/ESA Hubble Space Telescope. Image credit: X-ray: NASA/CXC/UCL/W.Dunn et al, Optical: NASA/STScI.The composite images above show Jupiter and its aurora during and after a CME’s arrival at Jupiter in October 2011. The impact of the CME on Jupiter’s aurora was tracked by monitoring the X-rays emitted during two 11-hour observations. The scientists used that data to pinpoint the source of the X-ray activity and identify areas to investigate further at different time points. They plan to find out how the X-rays form by collecting data on Jupiter’s magnetic field, magnetosphere and aurora using Chandra and ESA’s XMM-Newton.
UK observers with a clear sky an hour before sunrise on Friday 28 October should look very low in the east-southeast to see the slim crescent of the 27-day-old Moon less than four lunar diameters away from largest planet Jupiter. The Moon and Jupiter are also joined by third-magnitude double star gamma (γ) Virginis, commonly known as Porrima.
The Gemini Planet Imager instrument has discovered and photographed its first planet. Dubbed 51 Eridani b, the body is a methane-enshrouded gas giant that is the most Jupiter-like exoplanet ever directly imaged, in a planetary system just 20 million years old. It may hold the key to understanding how large planets form in the swirling accretion discs around stars.
Jupiter is two months past opposition on 10 August, so you need to be looking low in the southern sky of the British Isles around sunset if you wish to catch the solar system’s largest planet at its best. If you time it right and the weather obliges, Jupiter’s Great Red Spot makes multiple appearances while the planet’s Galilean moons play hide and seek. Welcome to our August 2019 Jovian observing guide.
