A massive stellar flare on a baby star has been spotted by astronomers, shedding light on the origins of potentially habitable exoplanets.
One of the largest ever seen on a star of its type, the huge explosion of energy and plasma is around 10,000 times bigger than the largest solar flare ever recorded from our own Sun.
The discovery is detailed in a paper for the Monthly Notices of the Royal Astronomical Society and reveals how this huge 'tantrum' could even perturb the material orbiting a star which would create the building blocks for future planets.
The flare was seen on a young M-type star named NGTS J121939.5-355557, located 685 light years away. At around 2 million years old, it is what astronomers refer to as a pre-main sequence star which is yet to reach the size that it spends the majority of its life-cycle.
It was observed as part of a large flare survey of thousands of stars by University of Warwick PhD student, as part of a project searching for explosive phenomena on stars outside our solar system. He used the Warwick-led Next-Generation Transit Survey (NGTS) telescope array in Chile which is designed to find exoplanets by collecting brightness measurements of hundreds of thousands of stars and is based at the European Southern Observatory's Paranal Observatory. His attention was drawn to NGTS J121939.5-355557 as it had one of the largest flares seen in these types of stars.
A stellar flare occurs when the magnetic field of a star rearranges itself, releasing huge amounts of energy in the process. This accelerates charged particles, or plasma, within the star which crash into its surface, heating it up to around 10,000 degrees. That energy produces optical and infra-red light, but also x-rays and gamma rays that can be picked up by telescopes on Earth and in orbit.
Magnetic fields on M stars are a lot stronger than those on our own sun and the astronomers calculated that this size of flare is a rare event, occurring anywhere from every three years to twice a decade.
The X-rays from these large flare events are thought to affect the formation of 'chondrules', flash-melted calcium-aluminium-rich grains in the star's proto-planetary disc. These gather together into asteroids that eventually coalesce into orbiting planets. The study adds to our understanding of how flares 'perturb' the proto-planetary disc, moving around the material that impacts on planet formation and affecting the eventual structure of a planetary system.