It’s pretty rare to see cosmic phenomena with the naked eye, so when they do happen, it’s a good idea to sit up and pay attention. Just like the recent solar eclipse and phenomena like the aurora borealis that we’ve seen in our skies, there’s another dazzling event you’ll want to see ASAP. It’s time to join the hordes of NASA scientists and astronomers eagerly awaiting the cosmic explosion that will light up the night sky—and you don’t even need a telescope to see it.
In February 2016, astronomers announced that the T Coronae Borealis star system had entered a “phase of unprecedented activity.” Eight years later, this solar activity could result in a nova event large enough to be visible to the naked eye from Earth.
In a nova, a white dwarf attracts solar material from a nearby red giant. When the heat and pressure become too great, a thermonuclear explosion results. The white dwarf then appears brighter in the sky, but it does not disintegrate, and once the explosion dissipates, the star returns to its original brightness. This massive eruption is a nova.
The nova is visible to the naked eye for more than a week after its appearance. During this time, it will look like a new star has appeared in the sky. According to NASA, the explosion could occur at any time, day or night, between now and September, although scientists estimate it could take longer.
What will the nova look like?
Those lucky enough to be observing the night sky at the start of the show may be disappointed. The show won’t seem as explosive as it actually is. According to Dr. Elizabeth Hayes, project scientist for the Fermi Gamma-ray Space Telescope at NASA’s Goddard Space Flight Center, a person observing the sky as the event occurs won’t see anything right away.
“If they continue to observe for the next 24 hours, they will see a faint star appear and gradually brighten,” Hayes told CNET. “Of course, someone on Earth will have their view interrupted by the Earth’s rotation.”
“The best time to observe the nova with the naked eye will be about a day after the eruption begins,” Hayes said. “But the nova will be visible to the naked eye for a few days.”
This NASA video shows what it looks like.
The last nova in this star system was in 1946.
The cosmic light show is provided by T Coronae Borealis, also known as the Blaze Star or T CrB. It is a binary star system comprising a white dwarf and an ancient red giant about 3,000 light-years from Earth in the northern corona of the Milky Way. It is part of the constellation Corona Borealis which forms a distinctive “C” shape in the sky, mainly during the summer months.
The white dwarf, the remnant of a dead star, is about the size of Earth but the same mass as the Sun. The aging red giant, on the other hand, is a dying star that is shedding matter into space. The massive gravitational pull of the white dwarf pulls the matter ejected by the red giant along with it. Once the white dwarf has accumulated enough matter, the heat increases so much that it causes a runaway thermonuclear reaction. This explosion is called a nova.
The last nova of this star system occurred in 1946. It is a cycle that has continued since its discovery more than 800 years ago.
“This is a unique event that will create many new astronomers, giving young people a cosmic event that they can observe for themselves, ask their own questions and collect their own data,” said Rebekah Hounsell, an assistant research scientist at NASA’s Goddard Space Flight Center. “This will nurture the next generation of scientists.”
Where is Corona Borealis?
You’re probably not as familiar with Corona Borealis as you are with easier-to-spot constellations, like the Big Dipper. It’s hard to find in the night sky unless the sky is clear. Light pollution from big cities can also make it harder to find.
According to NASA, the easiest way to find Corona Borealis is to find Vega and Arcturus, the two brightest stars in the Northern Hemisphere. (Skywatching apps for your phone can help.) From there, you can essentially draw an imaginary line between the two. Corona Borealis sits almost exactly in the middle. You can use the graph below to see what we mean.
The nova will occur in the constellation Corona Borealis, near the constellation Hercules and just between Vega and Arcturus.
You can also look for the constellation Hercules and Corona Borealis will be right next to it. Keep in mind that you can’t see the star in question until the nova occurs, so if you look up at the sky before it happens, the location where the nova will occur won’t be visible.
When will the T CrB nova occur?
No one knows for sure. Astronomers and scientists only know that the nova should erupt at any moment. Most agree that the eruption should occur before September, although it could take longer.
Since the nova could occur at any time, NASA is relying on citizen astronomers and space enthusiasts to announce it as soon as it happens.
“Using social media and email, observers will send instant alerts,” said Elizabeth Hays, head of NASA Goddard’s Astroparticle Physics Laboratory. “We’re counting on that global community interaction with T CrB again.”
Early detection can also help NASA collect more data about the event to better understand its mechanics.
“We will observe the nova eruption at its peak and during its decline, as the visible energy of the eruption fades,” Hounsell said. “But it is equally critical to obtain data during the initial phase of the eruption, so the data collected by the passionate citizen scientists who are currently on the lookout for the nova will contribute significantly to our discoveries.”
Do I need a telescope to see the nova?
No. NASA says the nova will be visible to the naked eye on a clear day. It will also be quite bright, so it should be quite visible. But as always, people with telescopes and binoculars will have a better view.
People with powerful telescopes will see the changes more definitively.
“A telescope that measures the optical spectrum would see something very different from the spectrum of a red giant,” Hayes said. They would see “nova flares emitting spectral lines at specific wavelengths. These tell us about the elements of the explosion and how fast the shock wave propagates away from the white dwarf.”
The nova won’t look like an explosion like the ones you see in Michael Bay movies. It will just look like another star in the sky that wasn’t there before.
What is the difference between a nova and a supernova?
Most people have heard of the term “supernova.” It’s the final gasp of a star as it burns out. But that final gasp is also the largest explosion ever observed by humans, with the star violently ejecting matter into space. Scientists believe that supernovas are responsible for the presence of elements heavier than iron in the universe. Interestingly, even the iron in your blood can be attributed to supernovas or similar cosmic explosions.
A nova, on the other hand, requires two stars. One is always a white dwarf, while the other is usually a red giant.
There are other types of novae as well. Hypernovae are supernovae that reach a certain size and brightness. Typically, they are about 10 times brighter than a standard supernova. Another type, an extremely rare kilonova, occurs when two neutron stars collide, releasing an incredible gravitational wave as well as electromagnetic radiation.