In new results from the Kepler data that are published in the Monthly Notices of the Royal Astronomical Society, astronomers, working with lead author R Ridden-Harper, find that a hungry white dwarf star may be chowing down on a nearby brown dwarf. 

Brown dwarfs are odd objects that aren’t quite planets, and aren’t really stars. With masses between 10 and 80 times the mass of Jupiter, some brown dwarfs will undergo short lived nuclear burning of tritium – heavy hydrogen atoms with a surplus of neutrons. This particular brown dwarf orbits a white dwarf star so closely that the white dwarf star’s extreme gravity can tear material off the brown dwarfs surface. When the region around the white dwarf gets too bloated with material, that material can explode, creating a brilliant outburst we call a cataclysmic variable outburst. Only 100 systems of this particular combination – a white dwarf and brown dwarf – are known.

These outburst events are brief, and by luck Kepler just happened to be looking at this system in the lead up to and during a 2016 event that is being classified as a super-outburst. According to the press release, “Kepler captured the entire event, observing a slow rise in brightness followed by a rapid intensification. While the sudden brightening is predicted by theories, the cause of the slow start remains a mystery. Standard theories of accretion disk physics don’t predict this phenomenon, which has subsequently been observed in two other dwarf nova super-outbursts.” 

This paper uses data from a retired spacecraft, and shows us that even when a mission is retired, the freely available data is able to keep generating new science. The trick is, you have to have the mission to get the data to make the science.

You can find out more about the science at:

• Astronomers spot ‘vampire’ star sucking life from victim (ANU)
• NASA’S KEPLER WITNESSES VAMPIRE STAR SYSTEM UNDERGOING SUPER-OUTBURST (Hubblesite)