Get ready for a “new” star to appear in the night sky. Not really new of course, but a star that is now below the naked-eye visibility limit is gearing up for an outburst that will bring it within sight of the unaided eye for the first time since the 1940s.
Such a star is called a nova, Latin for “new”. The star, T Coronae Borealis, is actually composed of two stars: a red giant and a white dwarf. The white dwarf is a dense stellar core about the size of the Earth and its gravity is pulling gas off the red giant. This gas accumulates on the white dwarf’s surface before detonating in a thermonuclear explosion, causing the star to temporarily brighten. Eventually, it returns to normal and the cycle repeats.
In the case of T Coronae Borealis, historical observations show that it explodes approximately every 80 years. Astronomers expect it to blow any time between now and September. The chart shows the view looking east from London at about 22.00 BST this week, and marks the location to keep an eye on. When it erupts, the star is expected to reach the same brightness as Alphecca, the brightest star in its home constellation.
