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 display occurs when a white dwarf star explodes, increasing its brightness ten thousand times. Even with the naked eye, we can enjoy its glory from millions of miles away, and another show will begin very soon. NASA scientists and astronomers are eagerly waiting to see it, just as we have longed to see solar eclipses and the Aurora Borealis for the past few years.
In a nova event, a white dwarf star pulls solar material from a nearby red giant. When the heat and pressure from this build up too much, the result is a thermonuclear explosion. This makes the white dwarf appear brighter in the sky, but it does not disintegrate, and once the explosion dissipates, the star returns to its original brightness. This massive explosion is a nova.
The nova can be seen with the naked eye for more than a week after it occurs. For that period, it will seem as if a new star has appeared in the sky. According to NASA, the eruption 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 one from this star system was in 1946
The cosmic light show is courtesy of 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 about 3,000 light years from Earth in the Northern Crown of the Milky Way. It is part of the Corona Borealis constellation that makes a distinctive C shape in the sky, mainly during the summer months.
A white dwarf, which is 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 that is spewing material into space. The massive gravitational pull of the white dwarf is pulling in material ejected from the red giant. Once the white dwarf has accumulated enough material, the heat builds up enough to cause a runaway thermonuclear reaction. This explosion is called a nova.
The previous nova from this star system occurred in 1946. It’s a cycle that has been going on since it was first discovered more than 800 years ago.
“It’s a once-in-a-lifetime event that will create a lot of young astronomers out there, giving young people a cosmic event 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 Goddard Space Flight Center. “This will feed the next generation of scientists.”
Where is the Corona Borealis?
You’re probably not as familiar with the Corona Borealis as you are with the more easily distinguishable constellations, like the Big Dipper. It’s hard to find in the night sky if it’s not clear. Light pollution from big cities can also make it harder to find.
NASA says the easiest way to find the 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 basically draw an imaginary line between the two. Corona Borealis is almost in the middle. You can use the chart below to see what we mean.
Alternatively, you can also look for the constellation Hercules and the Corona Borealis will be right next to it. Remember that you can’t see the star in question until the nova occurs, so if you look up in the sky before it happens, the place where the nova will occur won’t be visible.
When will it be nova?
Nobody knows for sure. Astronomers and scientists only know that the nova will explode at any time. Most of them agree that the nova should be done anytime before about September, although it may take longer.
Since the nova can happen at any moment, NASA is relying on citizen astronomers and space enthusiasts to call it when the nova occurs.
“Using social media and email, (observers will) send instant alerts,” said Dr. Elizabeth Hayes, head of the Astroparticle Physics Laboratory at NASA Goddard. “We’re counting on that global community interaction again with T CrB.”
Early detection could also help NASA gather more data about the event to better understand its mechanics.
“We will observe the nova event at its peak and through its decay as the apparent energy of the explosion fades,” Hounsell said. “But it’s just as critical to get data during the early outburst—so the data collected by those eager citizen scientists who are now looking for novae will contribute dramatically to our findings.”
Will 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. Nova will not 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 visible. 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 gasp of a star as it darkens. However, this last dying gasp also happens to be the largest explosion ever witnessed by humans, as the star violently ejects material into space. Scientists believe that supernovae are responsible for elements heavier than iron in the universe. Oddly 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 other types of nova. Hypernovae are supernovae that reach a certain size and luminosity. Typically, they are about 10 or more times brighter than a standard supernova. Another type, an extremely rare kilonova, occurs when two neutron stars collide, releasing an incredible gravitational wave along with electromagnetic radiation.
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Image Source : www.cnet.com