Every 80 years, the heavens give us a rare gift: a stellar explosion called a nova that surpasses all other cosmic wonders. This celestial fireworks show takes place when a white dwarf star erupts, increasing its brightness ten thousandfold. Even with the naked eye, we can enjoy its glory from a million miles away, and another show is about to start. NASA scientists and astronomers are waiting patiently to see it, just as we have longed for solar eclipses and the Aurora Borealis in recent years.
In a nova event, a white dwarf star attracts solar material from a nearby red giant. When the heat and pressure become too high, the result is a thermonuclear explosion. This causes the white dwarf to appear brighter in the sky, but it does not disintegrate, and once the explosion dissipates, the star returns to its original brightness. That enormous eruption is a nova.
The nova can still be seen with the naked eye for a week. During that period it will appear as if a new star has appeared in the sky. According to NASA, the explosion could happen anytime, day or night, between now and September, although scientists say it could take longer.
This NASA video shows what it looks like.
The last such star system was in 1946
The cosmic light show is thanks to T Coronae Borealis, also known as the Blaze Star or T CrB. It is a binary star system consisting of a white dwarf and an ancient red giant located about 3,000 light-years from Earth in the northern crown of the Milky Way. It is part of the Corona Borealis constellation which makes a distinctive C-shape in the sky especially during the summer months.
The white dwarf, the dead remnant of a star, is about the size of Earth but has the same mass as the Sun. Meanwhile, the aging red giant is a dying star ejecting material into space. The white dwarf’s enormous gravity pulls in the red giant’s ejected material. Once the white dwarf has accumulated enough material, the heat increases so much that a runaway thermonuclear reaction occurs. That explosion is called a nova.
This star system’s previous nova occurred in 1946. It’s a cycle that has been going on since its discovery more than 800 years ago.
“It is a once-in-a-lifetime 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 Dr. Rebekah. Hounsell, an assistant research scientist at NASA’s Godard Space Flight Center. “It will fuel the next generation of scientists.”
Where is Corona Borealis?
You’re probably not as familiar with Corona Borealis as you are with easier-to-recognize constellations like the Big Dipper. It is difficult to find in the night sky unless it is clear. Light pollution from big cities can also make it harder to find.
NASA says the easiest way to find Corona Borealis is to find Vega and Arcturus, the two brightest stars in the Northern Hemisphere. (Skygazing apps for your phone can help with this.) From there you can essentially draw an imaginary line between the two. Corona Borealis is almost in the middle of it. You can use the chart below to see what we mean.
The nova will take place in the constellation Corona Borealis near the constellation Hercules and right between Vega and Arcturus.
Alternatively, you can also look for the constellation Hercules, which Corona Borealis is located right next to. Keep in mind that you won’t be able to see the star in question until the nova explodes. So if you look at the sky before it happens, the spot where the nova will happen won’t be visible.
When will the nova take place?
No one knows for sure. Astronomers and scientists only know that the nova could erupt at any time. Most of them agree that the nova should happen sometime before September, even though it could take longer.
Because the nova can happen at any time, NASA trusts that astronomers and space enthusiasts will report when the nova occurs.
“Using social media and email, observers send immediate alerts,” says Dr. Elizabeth Hayes, head of the Astroarticle Physics Lab at NASA Goddard. “We are once again counting on that global community interaction with T CrB.”
Early detection can also help NASA collect more data about the event to better understand its mechanics.
“We will observe the nova event at its peak and during its decay, as the visible energy of the eruption fades,” Hounsell said. “But it is just as important to obtain data during the early rise to the eruption – so the data collected by those enthusiastic citizen scientists now searching for the nova will dramatically contribute to our findings.”
Do I need a telescope to see the nova?
No. NASA says the nova will be visible to the naked eye on a clear night.
It is important to know what to look for. The nova won’t look like an explosion like you see in Michael Bay movies. It will just look like another star in the sky that wasn’t there before.
It will also be quite bright, so it should be quite noticeable. Those with telescopes and binoculars will have a better view.
What is the difference between a nova and a supernova?
Most people have heard of the term ‘supernova’. It is the last dying sigh of a star when darkness falls. However, that last dying gasp is also the largest explosion ever seen by humans, as the star violently ejects material into space. Scientists believe supernovae are responsible for elements heavier than iron entering the universe. Strangely enough, even the iron in your blood can be traced back to supernovae or similar cosmic explosions.
A nova, on the other hand, requires two stars. One star is always a white dwarf, while the other is usually a red giant.
There are also other types of novas. Hypernovae are supernovae that reach a certain size and brightness. Typically they are about 10 times or more brighter than a standard supernova. Another type, an extremely rare kilonova, is formed when two neutron stars collide, releasing an incredible gravitational wave along with electromagnetic radiation.