A new star is about to light up, expected all over the world: it will also be visible to the naked eye


By John

There is great anticipation all over the world for the new light that could light up in the sky at any moment, from now until the end of summer. It belongs to a star that shines periodically again, at intervals of about 80 years. Is called T Coronae Borealisor T CrBis about 3,000 light years away and the last time it shone in the sky was 1946. Before that it appeared in 1866 and there are also very ancient reports.

Unique features of the T Coronae Borealis

Making the event even more particular is the fact that there are only five similar stars in the Milky Way. It is actually a pair of stars, i.e. a binary system. «There are two actors staging the phenomenon: a cold star and a white dwarf», explains astrophysicist Gianluca Masi, scientific director of the Virtual Telescope. “When the matter of the first is transferred to the second, exceptional luminosity occurs, comparable to that of the polar star.” The cold star is a red giant that becomes unstable as its temperature and pressure increase; when this happens, the star begins to expel its external layers and the white dwarf collects that matter on its surface until the latter, heating up, causes a thermonuclear reaction that generates the nova visible from Earth.

Previous events and future prospects

As happened in 1946 and 1866, this time too T Coronae Borealis recorded a rapid reduction in brightness, according to a pattern that seems to repeat what was observed shortly before 1946: a year before the new light shone in the sky, T Coronae Borealis it had suddenly gone dark. A pre-eruption drop in brightness, astronomers had defined it. The same thing happened in 2013: faint light, a phenomenon astronomers called a “pre-eruption dip.” In 2023, T CrB it darkened again, heralding a new light. For this reason, astronomers and amateur astronomers have begun to look for it all over the world, in the region of the sky between the stars Arcturus and Vega. When it shines again you won't need a telescope because T Coronae Borealis will be visible to the naked eye. According to predictions, if the pattern repeats again, the star could occur sometime between now and September 2024.

Importance of the phenomenon

«It is a star that lives in quiescence, but from time to time it displays exceptional brightness», says Masi. It is therefore a variable star. Such stars are generally “faint and distant”, but T Coronae Borealis it will be very close” and “we can't wait to have a complete picture of what is happening”, observes Elizabeth Hays, head of the Astroparticle Physics Laboratory at NASA's Goddard center. It is a so-called 'recurrent nova' and the its light could be visible for a few days, perhaps just over a week, before becoming so weak again as to be invisible for another 80 years or so. «It is a once-in-a-lifetime event – said Rebekah Hounsell of NASA's Goddard Center – which I believe will lead to the birth of many new young astronomers”.