Astronomers are closely monitoring the binary star system T Coronae Borealis (T CrB), anticipating a rare nova eruption that could become visible from Earth as early as 2025. Based on changes in brightness, scientists believe the anticipated explosion may happen at any moment.
T CrB, located about 3,000 light-years away in the constellation Corona Borealis, consists of a red giant and a white dwarf that orbit each other with a period of about 228 days. The system is classified as a recurrent nova, known for its periodic brightening, with documented eruptions occurring approximately every 80 years. The last documented brightening of T CrB occurred in 1946, with previous eruptions recorded in 1787 and 1866.
"Detailed observations of the star have revealed variations that suggest the imminent arrival of this long-awaited explosion," said astronomer Franck Marchis from the SETI Institute and Unistellar co-founder, according to IFLScience. Medieval archives also mention an explosion of T CrB dating from 1217, although the information is less precise.
Researchers have proposed probable dates for the next nova events of T CrB: March 27, 2025; November 10, 2025; June 25, 2026; and February 8, 2027. However, these dates are not certain due to the unpredictable nature of stellar explosions. "When you look more closely at the data of the past outbursts, you find that the time intervals of the successive events are an integer multiple of the orbital period," said astronomer Jean Schneider, according to IFLScience.
A nova occurs when a white dwarf star accumulates material from its companion red giant, leading to a thermonuclear explosion that makes the system so bright it becomes visible to the naked eye. Over time, the white dwarf in T CrB accumulates material from the red giant, leading to periodic nova explosions. Experts indicate that this is not a supernova in the classical sense—a star that collapses and dies—but a surface eruption generated by the accumulation of hydrogen in the white dwarf. Novae are not to be confused with supernovae; in a supernova, the star explodes, destroying the original star.
When the explosion of T CrB occurs, its brightness will increase about 1,500 times, making it comparable to the star Polaris, and will remain visible to the naked eye for several days before fading.
The exact timing of the explosion is an open question, and the thermonuclear reaction that causes the explosion is a complex phenomenon still poorly understood. While some astronomical events, like solar eclipses, can be predicted with remarkable accuracy, recurrent novae often escape any attempt at prediction. "The explosion might even extend into 2027," noted researchers, emphasizing the difficulty in forecasting such stellar phenomena.
Observations by professional astronomers and citizen scientists today might help predict future eruptions of T CrB and possibly many other recurring novae. Understanding the cycles of these novae could help predict not only the explosions of T CrB but also other similar systems in our galaxy. The study of these recurrent novae is crucial for scientists to better understand the physical processes at work in these binary systems. Monitoring novae enriches our understanding of the dynamics of dying stars and the mechanisms governing binary star systems.
Observers should look towards the constellation Corona Borealis in the eastern sky to locate T CrB when it erupts. It is positioned over the northeastern horizon at midnight and can be observed earlier in the second half of the year. The explosion will be visible from the northern hemisphere, with better observation conditions in clear skies and away from light pollution.
"It will give young people the opportunity to directly observe the universe, formulate their own questions, and collect data on their own. It will be a source of inspiration for the scientists of tomorrow," concluded Rebekah Hounsell from NASA's Goddard Space Flight Center.
The article was written with the assistance of a news analysis system.