The star system, about 3,000 light-years away, is expected to erupt as a recurring nova and brighten from an invisible object to a prominent star within hours. June 25 has been suggested as one possible date – but researchers stress that this is only a statistical prediction, and the eruption could occur earlier or later.
Astronomers and amateur observers await the eruption of T Coronae Borealis, a star system also known as the "Flame Star" and located in the constellation Coronae. If the eruption occurs, a seemingly new point of light will appear in the night sky and will be visible without a telescope for several days.
Despite headlines suggesting the event could happen as early as this week, there is currently no confirmed report of the start of the eruption. Attention is drawn to June 25, 2026, because it is one of four dates calculated by astronomer Jean Schneider of the Paris Observatory. This is not a date set following the detection of an immediate sign of an eruption, but an extrapolation based on the dates of previous eruptions and the system’s orbital cycle, which is about 228 days long. Two previous dates on the list – March and November 2025 – have already passed without an eruption, and the next date after them is February 8, 2027. Schneider himself warned that there is no proven physical model behind the calculation and that it should be treated with caution.
A white dwarf that "steals" material from a red dwarf
T Coronae Borealis is not a single star but a binary system. One of its components is a red giant – a star that has swelled up in the late stages of its life – and the other is a white dwarf, a small, dense remnant of a sun-like star. The white dwarf's gravity pulls gas, mostly hydrogen, away from the red giant. The material forms an accretion disk and eventually accumulates on the white dwarf's surface.
When the pressure and temperature in the hydrogen layer increase sufficiently, a rapid thermonuclear fusion reaction begins. The explosion throws some of the accumulated material into space and greatly increases the brightness of the system. Unlike a supernova, the white dwarf is not destroyed, so the process may repeat after a new layer of material has accumulated on it. (NASA Science)
This is why the event is called Nova returnsThe system's last well-documented outbursts occurred in 1866 and 1946, about 80 years apart. There are also historical accounts that may describe earlier outbursts, including a description from 1217 of a faint star that brightened briefly.
From a pale star to a visible object
In its normal state, T Coronae Borealis has an apparent magnitude of about 10, making it invisible to the naked eye. During an outburst, it may reach magnitude 2 or 3 – similar to the brightness of the North Star and prominent enough to be seen from urban areas, although dark skies will enhance the view. On the astronomical magnitude scale, a lower number indicates a brighter object. (Space)
The peak may occur within hours, after which the system is expected to fade rapidly. According to NASA, it may remain visible to the naked eye for a little less than a week, after which it can be continued to be observed with binoculars or a telescope. Because the bright phase is short, professional and amateur astronomers regularly monitor the region in the hope of detecting the beginning of the increase in brightness. (NASA)
How to find it from Israel
The Coronae Borealis group is also visible from Israel during the summer months. Its shape is a small arc or semicircle of stars, and it is located between the Hercules and Ursa Major groups. A convenient way to find the area is to identify the bright stars Vega and Arcturus and look for the arc of the Coronae Borealis between them. Before the eruption, strong binoculars or a telescope are needed to see T Coronae Borealis itself; after the eruption, a prominent point of light will appear where there is usually no visible star. (NASA)
The event is also expected to be important scientifically. Modern gamma-ray telescopes, X-ray observatories, and satellites were not available for the 1946 outburst. This time, observations are planned at a range of wavelengths, from radio and visible light to X-ray and gamma rays, to track the evolution of the shock wave, the ejected material, and its interaction with the red giant's stellar wind. (NASA)
Questions and Answers
Will a new star really appear in the sky this week?
Not necessarily. June 25, 2026, has been suggested as a possible date for an eruption, but this is not a certain prediction. The eruption could occur this week, in a few months, or even later. Astronomers continue to monitor the system.
What is T Coronae Borealis?
This is a binary system located about 3,000 light-years away, in the constellation Coronae. It consists of a red giant and a white dwarf that are attracting material from the neighboring star.
Why is it called a "new star"?
When the flare begins, an object that is normally invisible to the naked eye brightens rapidly and appears as a new point of light in the sky. In fact, it is not a new star but an existing star system whose brightness increases greatly for a short time.
What causes an outbreak?
Gas from the red giant accumulates on the surface of the white dwarf. When the pressure and temperature in the accretion layer become high enough, a sudden thermonuclear reaction begins, greatly increasing the brightness of the system.
Is this a supernova?
No. In a nova, the white dwarf survives the explosion, so the process can repeat in the future. In a supernova, a much more destructive event occurs, in which a star explodes or the white dwarf is destroyed.
Why is the outbreak considered rare?
The last recorded eruptions of T Coronae Borealis occurred in 1866 and 1946. This means that most people will only get one chance in their lifetime to see the system in an eruptive state.
How bright will it be?
At the peak of the eruption, it may reach magnitude 2 or 3, meaning it will be similar in brightness to the brightest stars in the night sky. Under suitable conditions, it will be visible to the naked eye.
How long will it be possible to see her?
The system may remain visible to the naked eye for several days, then gradually fade. It will be possible to observe it for a longer period of time with binoculars or a telescope.
Will it be possible to see the outbreak from Israel?
Yes. The Northern Crown constellation is visible from Israel on summer nights. It is located between the constellations Hercules and Ursa Major and appears as a small bow of stars.
Is the eruption dangerous to the Earth?
No. The system is about 3,000 light-years away, and the eruption is not expected to affect Earth. It is an observational and scientific event only.
Why are astronomers interested in the event?
This will be the first outburst of the system in an era when it can be monitored by space and ground-based telescopes in radio, visible, ultraviolet, X-ray, and gamma-ray spectra. The data could help understand how material accumulates on white dwarfs and how novae develop.
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