Skywatchers around the world should gear up for an incredible celestial event, as the binary star system T Corona (T CrB) is expected to experience a magnificent nova explosion sometime between now and September. This explosion could occur at any moment.
This remarkable outburst will change T CrB from an unseen star to one as bright as Polaris.
Novae like the one predicted for T CrB happen in binary star systems where a white dwarf orbits closely with a companion star.
“A nova is a binary system in which two stars orbit close to each other.”Dr. Darren Baskill, an Astronomy lecturer at the University of Sussex, tells BBC Science Focus, “About half of the stars in the night sky are double star systems.”
These should not be confused with supernovae, the dramatic explosions that occur when a massive star dies and can illuminate an entire galaxy momentarily.
White dwarfs accumulate material from their companion stars through a process called accretion. When this material reaches a critical temperature, it triggers powerful hydrogen fusion reactions.
The outcome? A nuclear explosion that ejects gas from the white dwarf, significantly increasing the system’s brightness.
“This sudden onset of nuclear fusion causes the surface gas layer to become even hotter, triggering more nuclear reactions and leading to a brightening of the star – a nova explosion,” Baskill explained.
While most novae are unpredictable and observed only once, T CrB is a recurrent nova that erupts roughly every 80 years. If you miss it this time, you’ll have to wait until around the year 2100!
T CrB is the closest star system to Earth, about 3,000 light years away, and is bright enough to be seen with the naked eye even in areas with moderate light pollution.
The nova explosion of T CrB is so distant from Earth that it has just reached us. Since then, there have been over 35-40 similar explosions, and the light signals from each one are yet to reach us.
Previous eruptions of T CrB were recorded in 1866 and 1946, with a noticeable brightness decrease before the latter eruption. A similar decline was noted earlier this year, hinting at a potential new explosion.
“Amateur astronomers around the world have observed slight brightness changes in this star every three to four months,” Baskill noted. “In 1945, when this happened, the gas on the white dwarf’s surface exploded dramatically within a year, causing a nova. Is it possible that the same scenario could repeat soon?”
How to witness a nova explosion
Although T CrB is currently too dim to be seen without help, a nova eruption would be visible without any special equipment. Amateur telescopes can observe T CrB before the eruption.
To prepare, stargazers should study Corona Borealis using a star chart or a smartphone app.
This preparation will enhance the spectacle when a nova suddenly emerges and brightens a familiar constellation.
Dr. Mark HollandsResearchers from the University of Warwick advise: “The nova will be visible to the naked eye for a few nights, reaching a brightness similar to other stars in Corona Borealis. If you miss that window, it should be visible for several weeks with binoculars.”
Though our Sun will become a white dwarf in billions of years, it will not undergo a nova explosion due to the lack of a companion star.
Don’t miss this once-in-a-lifetime astronomical event and seize the rare chance to witness a nova explosion bright enough to see without a telescope.
About the experts
Darren Baskill is an Outreach Officer and Lecturer at the University of Sussex. She previously taught at the Royal Observatory, Greenwich, where she founded the observatory’s annual ‘Astronomy Photographer of the Year’ competition.
Mark Hollands is a Postdoctoral Research Fellow at the University of Warwick, focusing on white dwarfs. His work appears in journals like Natural Astronomy, Monthly Bulletin of the Royal Astronomical Society, and he has spoken at conferences worldwide.
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Source: www.sciencefocus.com
