Skywatchers will soon have a chance to see a rare astronomical event over the coming week as a pair of stars is expected to explode and light up the night sky for at least a week.
A binary star system called T Coronae Borealis (or T CrB) sits about 3,000 light years away from Earth. You can’t see it right now, but you will be able to soon. Astronomers say the two stars are going to explode and the light display will be as bright as the North Star.
This event happens every 80 years in this star system. So, the explosion is regular, and it is only a “nova,” not a “supernova.” A supernova is the name of the final explosion that destroys a star. T CrB will still exist after its regular 80-year heat-up period.
Rebekah Hounsell is a research scientist at the NASA Goddard Space Flight Center. In a statement, she said the display is a “once in a lifetime event,” and she thinks the wonder of the sight will inspire more people to become astronomers.
So what’s going on in T CrB? One of the two sons is a white dwarf. This is a star that’s about the size of the Earth when measured in distance, but it has the density and mass of the sun. The other star is a red giant, a very old star that has been slowly cooling off. The stars orbit each other due to their interlocked gravitational fields. But the denser white dwarf is slowly siphoning material off the red giant; hydrogen specifically.
As the red giant shrinks from losing hydrogen, the white dwarf grows. At a certain point, the temperature on the red giant increases massively to 360,000 degrees F. At the same time, the white dwarf releases its outer layers in a fiery explosion, which makes T CrB visible to observers with the naked eye.
Astronomers do not know the exact time and date when the light show will kick off, but it is expected this week, and is expected to last for at least a week. If you’re interested in watching, it’s best to be away from cities with a lot of light pollution. Go outside after dark on a clear night and look to the northeast. T CrB will be visible in a constellation called the Northern Crown.
