Astronomers chance upon a ‘vampire’ star feeding frenzy
New project makes good use of data from an old telescope.
Astronomers led by the Australian National University (ANU) have found a “vampire” star in the midst of a feeding frenzy, with the help of an automated program that is sifting through archived data from the decommissioned Kepler Space Telescope.
The new program, they say, acts like a detective to find clues of very fast, mysterious explosions in the universe.
In this case, it found a dwarf nova, which comprises a white dwarf – the dense remains of a star – gorging on a much smaller brown dwarf – a failed star resembling a planet.
“The rare event we found was a super-outburst from the dwarf nova, which can be thought of as a vampire star system,” says ANU’s Ryan Ridden-Harper, lead author of a paper in the Monthly Notices of the Royal Astronomical Society.
“The incredible data from Kepler reveals a 30-day period during which the dwarf nova rapidly became 1600 times brighter before dimming quickly and gradually returning to its normal brightness.
“The spike in brightness was caused by material stripped from the brown dwarf that’s being coiled around the white dwarf in a disc. That disc reached up to 11,700 degrees Celsius at the peak of the super-outburst.”
The new program aims to find rare astronomical events that evolve rapidly, over hours or days – such as gamma ray bursts from core-collapse supernovae, colliding neutron stars or potentially those not seen before through optical telescopes.
The discovery of the dwarf nova was unexpected but highlights the value of extending the use of Kepler data, says ANU co-author Brad Tucker.
“We’ve used it to see stars as they explode, the secret lives of black holes and now things previously missed: this vampire star that had been lurking in the darkness of space,” he says.
The next steps include extending the project to include data from the Transiting Exoplanet Survey Satellite (TESS).
“This will give us the best understanding of the most rapid explosions in the universe. Along the way, we might discover some rare events that no other telescope could find,” Ridden-Harper says.
The project is a collaboration with the Space Telescope Science Institute (STScI) and the University of Notre Dame in the US.