Rare Appearance of Two Novas at Once Illuminates the Southern Sky. Here’s How to Get a Chance to See It
The “new stars” are best seen from the Southern Hemisphere, but people have spotted them from the United States by looking near the southern horizon
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The Southern Hemisphere skies have two “new stars” visible to the naked eye. Though they appear as points of light like any other star, each one was caused by a stellar explosion called a nova. They flashed into the night sky within about one week of each other and will be visible for a limited time.
The rare multiple nova event started on June 12, when astronomers spotted the first nova, known as V462 Lupi, in the Lupus constellation. They found it with a sky survey telescope, but its brightness later became visible to the naked eye, reports Spaceweather.com. While a single nova is enough to get sky-watchers excited, on June 25, astronomers identified another one, called V572 Velorum, in the constellation Vela.
About 46 novas per year explode in the Milky Way—but since many are very far away, spotting one with the naked eye in the night sky is uncommon. Naked-eye nova events usually happen once every couple of years, as Juan Luna, an astronomer at the National University of Hurlingham in Argentina, tells Science News’ McKenzie Prillaman.
At first, experts thought this double nova was unprecedented in written history. But Botswana-based astronomer Stephen James O’Meara uncovered a similar event seven years ago, when two novas reached brightness visible to the naked eye on March 22, 2018, as he tells EarthSky’s Marcy Curran.
Novas occur when two stars revolving around each other, called a binary system, create a thermonuclear explosion. The system consists of one star and a white dwarf, which is the leftover core of a dead star. The reaction begins to form when the white dwarf’s gravity pulls hydrogen-rich matter from its stellar companion. After a large amount gathers around the white dwarf, it leads to a fusion reaction and nuclear explosion, with its brightness reaching, on average, 200,000 times brighter than the sun.
Need to know: What’s the difference between a nova and supernova?
Even though novas are exceptionally bright, supernovas are brighter—reaching billions of times brighter than the sun at their peak. When a nova is over, the star system returns to normal, but a supernova tears the star apart.Sometimes, the nova can become bright enough for us to see from Earth, appearing like a new star in the sky that can last for days, weeks or months. After the explosion, the energy is so great that it pushes the two-star system apart. Eventually, gravity will pull them back together again, and the celestial dance of the white dwarf collecting energy from its companion star will start over. Typically, an explosion will occur again in approximately 1,000 to 10,000 years, possibly even longer.
The dual novas are visible in the night sky for a limited time. It’s hard to predict when the stellar pair will stop shining. Science News wrote on July 1 that the dual novas may still be seen in the sky for another four to five nights. “The sooner one gets out there to look, the better,” O’Meara tells the publication.
Both novas are better seen from the Southern Hemisphere. But onlookers in the northern United States have spotted V462 Lupi—it’s best to look just after sunset toward the southern horizon, reports Harry Baker for Live Science. In southern parts of the continent, such as Mexico, Texas and California, observers might be able to glimpse V572 Velorum.
Although both novas are past their peak luminosity, they remain visible in the night sky. Its color can be described as a warm yellow, while some images captured it with a red hue. Amateur astronomer Bob King writes for Sky &Telescope that this is due to the star system’s cooling.
Even as these novas burn brightly, astronomers are keeping their eyes on the sky for another explosion: a recurrent nova, which is due to happen soon. While it’s not a double nova event, astronomers are gearing up to see the “Blaze Star,” or T Coronae Borealis (T CrB), explode. The last time T CrB was seen was in 1946. This specific recurrent nova has been on track to explode approximately every 80 years, and ever since it dropped in brightness in March 2023, experts have been predicting that its next blast is imminent.
