Just as you start to feel overwhelmed by all of the troubles going on in the world around you, NASA discovers events happening throughout the universe that give us a reassuring “Things could be worse.” The latest comes from astronomers who search the vast array of universal scans made by the Kepler space telescope for strange anomalies. In archival data they missed the first time around, researchers at the Space Telescope Science Institute (STScI) in Baltimore and the Australian National University in Canberra found a white dwarf that showed a sudden, intense glow … a glow that came from a nearby brown dwarf that it was sucking the life out of. Vampire stars are a thing … should we be worried?
“The white dwarf is stripping material from the brown dwarf, sucking its essence away like a vampire. The stripped material forms an accretion disk around the white dwarf, which is the source of the super-outburst. Such systems are rare and may go for years or decades between outbursts, making it a challenge to catch one in the act.”
In a recent press release, NASA used the term “vampire” to explain what lead author and astronomer Ryan Ridden-Harper calls a less-descript “new WZ Sagittae-type cataclysmic variable” in his paper published in the Monthly Notices of the Royal Astronomical Society. The Kepler space telescope has been retired since 2018, but its nearly decade-long scans of the universe to search for exoplanets left a huge database that astronomers continue to study for minute anomalies that could be major stellar events.
“At 25 days after the peak brightness a bump in the light curve appears to signal a subtle rebrightening phase implying that this was an unusual type-A outburst. This is the only WZ Sge-type system observed by K2/Kepler during an outburst.”
Whatever it looks like close up, it can’t be good
Anomalies like that one. Only Kepler could have detected this unusual super-outburst where a previously unknown dwarf nova suddenly brightened by a factor of 1,600 over less than a day before slowly fading. The cause was the white dwarf that the brown dwarf is orbiting at an extremely fast rate of once every 83 minutes at a distance similar to that between Earth and the Moon. The white dwarf is a dense dying star with sufficient gravity to suck what energy and matter is left in the dead brown dwarf … a kind of death dance where the partners swing around connected by an accretion disk of matter that causes the super-outburst.
A recreation of two stars in a death dance?
“This type of dwarf nova system is relatively rare, with only about 100 known. An individual system may go for years or decades between outbursts, making it a challenge to catch one in the act.”
Yet Kepler did, due to its relentless pace of taking a snapshot every 30 minutes with a view that only this space telescope could have. This discovery has astronomers enthused to go back through Kepler’s data and search for more of these rare vampire stars. To answer the question: no, we don’t have to worry. The vampire is in the Ursa Major constellation and our own Sun is a long way from being in either a vampire or dying state.
Kudos to Kepler and to NASA. It’s nice to see that NASA still respects the knowledge and experience of an old-timer … a lesson for us all.
from Mysterious Universe https://ift.tt/2SlsnKb
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