'New' star expected to appear from rare explosive event—here's what you need to know

You may soon witness a “new star” from a once-in-a-lifetime celestial event that might happen any time between now and September. 

The rare outburst is set to appear in the constellation Corona Borealis as a "new" bright star called T Coronae Borealis (T CrB) or “Blaze Star.” According to the National Aeronautics and Space Administration (NASA), it's a binary system with a white dwarf star and red giant star.

“The stars are close enough that as the red giant becomes unstable from its increasing temperature and pressure and begins ejecting its outer layers, the white dwarf collects that matter onto its surface,” the agency explained. 

“The shallow dense atmosphere of the white dwarf eventually heats enough to cause a runaway thermonuclear reaction, which produces the nova we see from Earth,” it added. 

In this star system, the stars normally have a magnitude of +10, which is “far too dim to see with the unaided eye.” During the explosive star event, NASA said will increase to magnitude +2, allowing it to have similar brightness to the North Star, Polaris. 

Once it reaches its peak brightness, it will be visible to the naked eye using binoculars for several days or over a week before it dims again.

The nova outburst happens about every 80 years. According to NASA, this last occurred in 1946, and astronomers believe that this will show up in the sky again between this point and September this year. 

What you need to know

Astronomer and meteorologist Edmund Rosales told PhilSTAR L!fe that nova explosions happen when stars reach their “old age.”  

“Nauubos na ang helium and hydrogen gas niya, forming more heavier elements like carbon and iron. Nagiging unstable na ito until it explodes,” he explained.

“Supernova, which means new star, is the stage where a star explodes upon its end point. Ito ang general term kapag sumabog ang star. Kapag bright ito, tinatawag rin na supernova pero kapag hindi gaanong bright, nova lang,” he continued, adding that supernova is much brighter than brightest visible planets from the Earth like Venus and Jupiter. 

He said that since the "Blaze Star" only comes from a nova outburst, it may be visible to the naked eye. However, it won't be very noticeable since it will not be as bright as a supernova. 

“Para lang may bagong star tayo na makikita sa constellation ng Corona Borealis, a constellation that is visible in our night sky facing north direction,” he told L!fe, noting that it will not be as “dramatic” as it was from hundreds of years ago since our night sky is now affected by light pollution.   

According to Rosales, it's impossible to determine the exact date of its visibility in the sky.

“I just want to make it clear na lahat ng nakikita natin sa space are actually their image in the past depending on their distance to us,” he said. 

“Supernova and nova may last for several months kaya pwede ito makita sa naked eye. If this happens, ibig sabihin nito, kapag nakita nating sumabog na siya sa space, ang makikita natin sa Earth was many years ago na. Hindi ito real time 'pag nakita natin sa Earth. Sa sobrang layo niya, it takes many years for its light to travel in space bago umabot ito at makita sa Earth,” he explained. 

Rosales added that the said explosion may have already happened, and that we are just waiting when it will appear in today’s time. 

“Kapag nakita ito from this point on until September, that means many years na ito nangyari at ngayon lang umabot dito sa atin,” he said.