The skies have been quite exciting so far this year over southern Canada with April’s spectacular solar eclipse and May’s rare northern lights show. And now next up sometime this summer may be an exploding star visible to the naked eye.
“This could be a once-in-a-lifetime viewing opportunity as the nova ouburst only occurs about every 80 years,” according to this NASA blog.
The blog explains that T Coronae Borealis, or T CRB, which is in a star system in our Milky Way Galaxy located about 3,000 light years away from Earth, last exploded in 1946 and that astronomers believe it will do so again sometime before September 2024.
That stellar explosion, of course, would be nothing compared to another much closer, much bigger star to the earth that some feel is getting ready to not just nova, but supernova — Betelguese.
Now to keep it in perspective, astronomers are much more confident of the time frame of T Coronae Borealis’ imminent explosion than Betelguese which could be tomorrow, or (tens of) thousands of years from now.
T Coronae Borealis, said Elaina Hyde, assistant professor in York University’s department of physics and astronomy and the director of its Allan I. Carswell Observatory in Toronto, “is a pretty interesting star. We’re actually watching it at our observatory at the moment just to see what happens.”
The observatory, she said, “has a student-run crew and a 1-metre telescope which is the largest telescope on a Canadian campus, so by us observing it every night for a few hours we can hope to get lucky; we hope we’ll be able to capture some of that light curve (when it explodes).”
It’s nicknamed “the blaze star,” she said, adding that it’s “actually what’s called a nova which is when you have two stars going around each other and one of them accretes material and periodically explodes.”
The two stars are a red giant and a white dwarf, she explained, with the dense white dwarf basically attracting in the stuff from the bloated red star.
And every once in a while — or to be more specific about every 80 years — it “reaches a flash point and detonates in a runaway thermonuclear explosion,” according to this NASA primer.
The original white dwarf actually survives the explosion to start collecting material from the red giant — and explodes all over again!
Our own sun is destined to go through both the red giant and white dwarf phases, Hyde explained — but not until about 5 billion years from now when it has fused all its regular hydrogen fuel in its core, according to this primer on the life cycle of the sun from space.com.
Betelguese, on the other hand, is an entirely different type of star headed for a different type of explosion — a supernova.
It’s not just a red giant, but a red supergiant, so if it were in our solar system it would envelop all the planets out to Jupiter — according to this NASA explanation.
Unlike are own far smaller sun which essentially can’t fuse anything after it uses up all of its hydrogen and then helium, the supergiants can keep on fusing heavier and heavier elements “to carbon to oxygen to calcium and eventually all the way to iron,” according to this NASA explainer.
But that’s where the party stops. Iron just doesn’t fuse. And so basically there’s nothing to stop the massive star from just falling in on itself only to violently recoil in an explosion that can briefly burn brighter than the entire galaxy it’s in, according to this NASA primer on big stars.
And when it does blow, scientists expect its brightness could match that of a half to a full moon for a brief time in our night skies.
It’s already among the brightest stars in our night sky, according to this NASA article, as it’s both big and relatively close at about 450 light years.
The star has been in the news in the past few years as an unusual dimming event left some experts pondering whether it was about to blow, but the consensus is that scientists just don’t know exactly what stage it’s at and so can’t predict its demise with certainty — but probably not soon.
T CRB, on the other hand, is not visible to the naked eye and when it does go nova its brightness, according to Hyde, will boost it briefly to a bit below the brightness of Betelguese right now.
“You would kind of have to be looking for it in reasonably dark skies,” she said, adding that the real excitement would be that it’s “something new that we can see all of a sudden.”
Dr. Sarah Adams is a scientist and science communicator who makes complex topics accessible to all. Her articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
