In the vast theater of the universe, some stars capture our imagination more than others. Among these is Polaris, the “North Star,” Sirius, the brightest star in the sky; Betelgeuse, a red giant in Orion; and T Coronae Borealis, the “Blaze Star.” What’s that? You’re not familiar with T Coronae Borealis? This celestial body is a recurrent nova, a rare type of stellar system characterized by dramatic, periodic explosions. In 2024, T CrB is set to dazzle once again, showcasing the ever-evolving cosmos.
T Coronae Borealis is not new to the astronomical scene. It is located about 3000 light years from Earth, nestled within the constellation Corona Borealis. This constellation is recognizable by its small, semi-circular pattern of stars that resembles a crown. T CrB is located at the bottom left of the semi-circular pattern. It has had recorded explosions in 1866 and 1946. The 1946 event, in particular, allowed astronomers to observe the nova becoming significantly brighter, making it easily visible to the naked eye and momentarily one of the brighter stars in the sky. Astronomers anticipate that T CrB will erupt again before September 2024, adding to the excitement and providing opportunities for observation and study.
A recurrent nova consists of a binary star system featuring a white dwarf and a red giant locked in a gravitational embrace. A white dwarf is the small, dense leftover core after a star has used up most of its nuclear fuel and shed its outer layers. A red giant is a star in a later stage of life that has swelled in size and cooled, typically after exhausting the hydrogen in its core. In a recurrent nova system, the white dwarf accumulates material from its larger companion. This material builds up on the white dwarf until it ignites in a spectacular thermonuclear explosion, dramatically increasing the system’s brightness. This cycle of accumulation and explosion repeats periodically as the white dwarf continues to draw in and detonate material from the red giant.
T CrB, under normal conditions, is quite faint and usually not visible without a telescope. However, during a nova explosion, it becomes dramatically brighter, shining as brightly as Polaris, the North Star. This sudden increase makes T CrB easily visible to the naked eye. After the explosion, its brightness gradually fades over several weeks or months, returning to its original, less conspicuous state.
Despite the explosive nature of a nova, T Coronae Borealis poses no threat to our planet. The vast distance, 113 light-years, ensures that any radiation or material ejected from the nova is inconsequential by the time it reaches Earth. Instead, these events give us a front-row seat to some of the universe’s most spectacular phenomena.
To view T Coronae Borealis, start by using the star map above. This map illustrates the position of Corona Borealis in the night sky as observed from north Alabama. You may need to make slight adjustments north or south based on your exact viewing location, but it should be pretty close. Begin by facing east and then hold the map in front of you, rotating it so that the “Face East” label is at the bottom. Now, look up from the horizon the degrees indicated on the map to locate Corona Borealis. The map specifically marks where Corona Borealis will be positioned at 9:00 PM on the first day of each month from June through October. You’ll need to make adjustments depending on the date you are viewing. If you’re in a city with bright lights, like my experience in south Huntsville, you might find it challenging to spot the constellation due to the bright city lights washing it out. If you’re in a similar urban area, you might need to find a darker location outside the city to get a better view of the constellation.
In the interim, T Coronae Borealis will continue its cosmic dance, gathering mass until the conditions are ripe for another brilliant display. For those of us on Earth, it’s a reminder of the dynamic and vibrant universe we inhabit—a universe where even stars can put on a recurring show. So, keep watching the skies; the next chapter in the story of T CrB could unfold sooner than we think!