X-ray flares from Rho Ophiuchi A
The flickering view of massive star Rho Ophiuchi A as observed by ESA's XMM-Newton space observatory in 2016.
These and earlier observations from XMM-Newton showed this star to periodically throw off X-ray flares from its surface as it rotates – a behaviour somewhat akin to a cosmic lighthouse. Follow-up observations by the research team using ESO's Very Large Telescope confirmed that this star has a strong magnetic field, and that the X-ray flares are thus linked to an active magnetic region on the star's surface that rotates in and out of view.
This sequence is composed of 40 frames obtained between 22 and 23 February 2016, each taken approximately one hour apart. It shows the star's emission in the X-ray part of the spectrum; the lighter the blue tone, the stronger the emission, with white representing the maximum intensity. The intensity of Rho Ophiuchi A's X-ray emission can be seen to strongly increase at the beginning and end of this sequence; this is because the data cover more than one period of the star's X-ray flaring cycle, which lasts 1.2 days.