What are 'Zombie Stars?' NASA expert explains rare stellar phenomenon
It's called a "zombie star," and it occurs roughly every 80 years when the remnant of a dead star becomes visible to the naked eye following an explosion of a star system, according to NASA.
AUSTIN (KXAN) -- It may not be Halloween anymore, but scientists and astronomy experts are anticipating a spooky-sounding stellar phenomenon to light up the night sky soon.
It's called a "zombie star," and it occurs roughly every 80 years when the remnant of a dead star becomes visible to the naked eye following an explosion of a star system, according to NASA.
"You shouldn't be afraid of these stars. They're not coming to eat your brains or anything," Dr. Elizabeth Hays, an Astrophysicist with NASA, said.
NASA said there were indications earlier this year that a star system about 3,000 light-years from Earth was ready to “rise from the dead” and shine like a bright “new” star in the night sky.
The star system, known as T Coronae Borealis, or T CrB, experiences a violent explosion roughly every 80 years, NASA explained in a release. The explosion ignites the surface of one of its two stars, causing it to brighten so much it may be visible from Earth with the unaided eye.
The system is composed of two stars that orbit each other: a white dwarf, which is an Earth-sized remnant of a dead star, and a red giant, a star in its final death throes. White dwarfs are some of the densest objects in the universe. According to NASA, the white dwarf`s strong gravity siphons stellar material from its red giant partner, feeding from it like a vampire. When the accumulated layers reach a critical level, it explodes, in an event called a nova. The explosion only affects the surface layers, allowing the whole process to occur again and again.
Hays explained it like this: "This is a star that stopped burning like our sun, but it gets to have sort of a second life... Well, it's dead. It has a companion, a red giant star, that is feeding it material, kind of like a zombie. It's sucking in this material, spreading it out on its surface, it's going to reach a point that it triggers an explosion, and this is when we get to see light from that star again."
Animation of the nova that causes a "zombie star." (Courtesy: NASA) 
Animation of the nova that causes a "zombie star." (Courtesy: NASA) 
Animated White Dwarf Star with an accretion disk (Courtesy: NASA) 
Animated White Dwarf Star without an accretion disk (Courtesy: NASA) 
Photo of the T Corona Borealis set of stars taken through a telescope by Kevin Hartnett (Courtesy: NASA/Kevin Hartnett) 
Graph of T CrB brightness over time from the previous nova explosion in 1946. (Courtesy: NASA)
Based on historical observations of the system, scientists predicted the star would go nova again sometime this year, but the exact timing is tough to pinpoint.
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