A cosmic explosion will create a bright new star in the sky

This summer, a cosmic explosion is expected to create a new star that will be visible to the naked eye in the night sky. This phenomenon, known as a nova, will occur when the binary star system T Corona Borealis (T CrB) undergoes a sudden burst of light. Currently only observable with a telescope, the explosion will transform T CrB from a dim object to a bright dot visible overhead.

Novae eruptions occur in binary star systems, where two stars orbit each other. In the case of T Corona Borealis, the system consists of a large, dim star known as a red giant, and a smaller but denser star called a white dwarf. The white dwarf is the remnants of a star similar to our sun, with its dense nature resulting in strong gravity that enables it to consume material from its companion star.
According to Mark Hollands, an astronomer from the University of Warwick in the U.K., the ultra-dense white dwarf can acquire material from its companion star through a process called accretion. This leads to the accumulation of a layer of hydrogen on the white dwarf’s surface. When enough material has accumulated, the layer reaches a critical temperature and ignites hydrogen fusion. This triggers a powerful nuclear detonation that expels gas from the white dwarf’s surface, forming a hot luminous shell. As a result, the system becomes significantly brighter, creating a phenomenon known as a nova.

Unlike typical nova explosions, which occur only once and are difficult to predict, this particular system erupts repeatedly at intervals of approximately 80 years. Astronomers have already observed fluctuations in the system’s brightness, indicating that a nova event is expected to take place in the coming months. Once the eruption occurs, it will be easily visible in the sky.
Hollands suggests that the best course of action at present is to become acquainted with the section of the sky encompassing the constellation Corona Borealis, utilizing a star chart or a phone app. Once you become familiar with the stars visible in this region, you will truly appreciate the significance when an additional celestial body appears in the constellation in the coming months. The nova will be observable to the naked eye for a few nights and will achieve a comparable brightness to the other stars in the Corona Borealis constellation. However, even if you miss this initial opportunity, the nova will still be visible for a few weeks with the aid of a good pair of binoculars.