NASA reports that a “new star” that is expected to be a once-in-a-lifetime celestial sight will likely emerge in the night sky at any time between now and September.

Situated in the Milky Way between the constellations Hercules and Boötes, the projected brightening event, often called a nova, will take place in the Corona Borealis, also known as the Northern Crown.

A nova is the short-lived, abrupt explosion from a white dwarf star that has collapsed, whereas a supernova is the catastrophic death of a large star.

The “Blaze Star,” or T Coronae Borealis, is a binary system in the Corona Borealis that consists of an aged red giant star and a dead white dwarf star. When stars run out of hydrogen for nuclear fusion and start to fade, red giants are created. NASA estimates that in roughly 5 or 6 billion years, our sun will turn into a red giant, sputtering and growing as it releases layers of material and probably vaporizing the inner planets of the solar system. Earth’s future is yet unknown.

An explosive event occurs in T Coronae Borealis approximately every 79 years.

Because of their close proximity, the stars in the orbital pair interact furiously with one another. As the red giant heats up, it gets more and more unstable, shedding its outer layers that fall as matter onto the white dwarf star.

According to the space agency, the interchange of stuff leads the white dwarf’s atmosphere to steadily heat up until it undergoes a “runaway thermonuclear reaction,” which results in a nova, as seen in the animation below.

Watching the Sky as it Changes

Astronomers are closely monitoring T Coronae Borealis once more after it last had a spectacular outburst in 1946.

“Most novae happen unexpectedly, without warning,” said William J. Cooke, NASA Meteoroid Environments Office lead, in an email. “However, T Coronae Borealis is one of 10 recurring novae in the galaxy. We know from the last eruption back in 1946 that the star will get dimmer for just over a year before rapidly increasing in brightness. T Coronae Borealis began to dim in March of last year, so some researchers are expecting it to go nova between now and September. But the uncertainty as to when this will happen is several months — can’t do better than that with what we know now.”

It is anticipated that the star system, which is 3,000 light-years away from Earth and usually too faint to be seen with the unaided eye, would become as bright as Polaris, or the North Star.

When the nova reaches its maximum brightness, it will appear as if a new star has emerged. It can be seen with binoculars for a little over a week and without any equipment for a few days, after which it will fade and be lost from view for another 80 years or more.

The nova will be visible from the Northern Hemisphere, appearing in a little arc between the constellations Hercules and Boötes.

The Neil Gehrels Swift Observatory, located in space, will be used by astronomers to analyze the celestial event through ultraviolet and X-ray light, while the Hubble Space Telescope will be used to observe the nova.

Cooke stated, “Repeated novae like T Coronae Borealis provide us insights into the thermonuclear runaway that occurs on the surface of the white dwarf when the star goes nova and help us understand the mass transfer between the stars in these systems.”

Cooke remarked that the brightness of Nova Cygni, which he saw last in 1975, was comparable to that of T Coronae Borealis. It is not anticipated that Nova Cygni will encounter another explosion.