Million of years ago, before land connected Earth’s North and South American continents, about 21 million light years away an aged and bloated star gave up the ghost in dramatic fashion, dying in a cataclysmic supernova explosion.
On Friday, May 19, the light from that massive explosion finally reached the telescope of Japanese amateur astronomer Koichi Itagaki, who alerted the larger astronomical community: The supernova is now officially named SN2023ixf.
”Those photons that left that exploding star 20 million years ago have just now washed upon our shores from this long, long voyage through the cosmos,” says Grant Tremblay, an astrophysicist at the Harvard and Smithsonian Institute Center for Astrophysics, who has been actively spreading the word of the supernova on social media. “It’s happening now, in that we’re watching this thing finally explode, but the star has been dead for 20 million years.”
SN2023ixf is the closest supernova of its kind to Earth to pop off in five years, and the second closest in the past decade, according to NASA. That makes SN2023ixf a rare opportunity for astronomers to study the fiery death of a star. While too faint to be seen by the naked eye, the supernova should be visible to modest hobbyist telescopes, according to Tremblay.
Because the supernova will fade rapidly, stargazers have to seize the opportunity to observe it, including at multiple wavelengths.“The whole global community has rallied, from community astronomers to big multibillion-dollar space telescopes,” Tremblay says.
How to spot supernova SN2023ixf
SN2023ixf exploded in M101, also known as the Pinwheel galaxy, which is located in the night sky near the constellation Ursa Major. M101 is a bright spiral galaxy that lies face-on from the perspective of Earth and is a member of the Messier catalog of celestial objects, making it a common target for backyard astronomers. A 4.5-inch telescope should be sufficient to view the supernova, which will appear as a bright point of light, according to Sky and Telescope. You can find M101 by first finding Mizar, the star at the bend in Ursa Major’s tail, and following the five stars that lead away from it. Or, to be more precise, you want to point your telescope at a right ascension of 14:03:38.580 and a declination of +54:18:42.10.
Alternatively, the Virtual Telescope Project, a worldwide network of quality amateur telescopes, will livestream an observation of the supernova beginning at 6:30 p.m. Eastern on May 26.
“M101 is imaged by human beings every single night, all around the world, from hobbyists to all sky observatories like [The Sloan Digital Sky Survey], and so it was inevitable that this thing would be found eventually. But I just loved that Itagaki found yet another supernova,” Tremblay says. Itagaki is not a professional scientist, but he is the co-author of more than a dozen scientific papers based on his supernova observations. Tremblay says Itagaki has a “legendary” ability to spot supernovas, and he’s collecting these “discoveries like Thanos and infinity stones.” Itagaki’s findings include the 2018 supernova SN 2018zd, which proved to be an entirely new type of supernova in the universe.
Catching the bright burst of SN2023ixf on May 19, Itagki submitted his discovery to the International Astronomical Union’s transient name server website. From there, professional astronomers picked up the call, and within a few days, researchers began pointing major ground and space telescopes at the supernova, including the Hubble and James Webb Space Telescopes and the Chandra X-ray observatory.
All those telescopes will be measuring SN2023ixf’s light curve, “meaning the brightening and fading of this target in multiple wavelengths,” Tremblay says, on the spectrum from X-rays to optical light to infrared.
Lessons from an exploded sun
Those observations will help scientists characterize the star that exploded to create SN2023ixf, and more precisely define the type of supernova it is. Astronomers can already tell that SN2023ixf is a Type II, or “core collapse” supernova. This occurs when a massive star exhausts its nuclear fuel. The nuclear fusion reactions in its core can no longer push outward against the force of the star’s own gravity. The star’s core collapses in on itself, and then explodes outward in less than a second.
“This shock wave propagates outward, and it plows up gas in the ambient surroundings that can light up in all different wavelengths,” Tremblay says. Studying how that afterglow evolves over time will tell scientists about the mass and make up of the late star.
And the makeup of the star is connected to life on Earth—and life anywhere else in the cosmos, if it exists. Stars increase chemical complexity throughout their life cycles: They formed from primordial hydrogen after the Big Bang, fusing it first into helium and then into heavier elements right up to iron. When those stars die in supernovas, the intense heat and pressure form all of the known elements heavier than iron, and seed them throughout the cosmos, providing the raw material for rocky planets and life itself. “The story of life in the universe can be reduced, in many ways, to the story of increasing complexity,” Tremblay says.
The explosion of SN2023ixf is literally shedding light on the process that brought human beings into existence. Though the supernova will rapidly fade, it will remain an object of study for years to come, according to Tremblay. In the meantime, he says, the worldwide excitement around the supernova “is a beautiful illustration of the fact that the global public so effortlessly shares in our wonderment of the cosmos. An exploding star in a distant galaxy just lights up people’s hearts.”