Galaxy UGC 5460 in Ursa Major was host to the supernova SN 2022esa (Credit : ESA/Hubble & NASA)
Have you ever wondered what happens when a massive star dies? Most of us picture a spectacular explosion—a brilliant farewell lighting up the cosmos. But astronomers thought the universe's biggest stars had other plans. They believed these giants would simply vanish, collapsing into black holes without so much as a whisper.
Then came SN 2022esa.
Welcome to FreeAstroScience, where we break down the universe's greatest mysteries in plain language. Today, we're exploring a supernova that broke all the rules—a cosmic rebel that refused to die quietly. This discovery is rewriting textbooks and changing how we think about the birth of black holes. Grab your coffee, settle in, and let's journey together through one of the most exciting astronomical finds of our time.
What Did Astronomers Believe About Massive Star Deaths?
For decades, we had a neat story about stellar death. Small and medium stars die in slow, beautiful ways—shedding their outer layers like cosmic butterflies emerging from cocoons. The biggest stars? We thought they went out with a bang, creating supernovae visible across galaxies.
But here's where it got strange. When a star exceeds roughly 30 times the mass of our Sun, astronomers expected something different. These behemoths were supposed to skip the fireworks entirely. The thinking went like this: the star's gravity becomes so overwhelming that nothing can stop the collapse. No explosion. No light show. Just a quiet implosion into a black hole—a gravitational point of no return from which not even light can escape.
Think of it like a building demolition. Normal demolitions are loud, dusty affairs with debris flying everywhere. But imagine a building so heavy it just... sinks into the ground silently. That's what we expected from the most massive stars.
This assumption shaped how we understood black hole formation for years. If true, it meant the universe's most extreme objects were born in darkness, hiding their origins from our telescopes forever.
How Did SN 2022esa Change Everything?
On March 12, 2022, the Asteroid Terrestrial-impact Last Alert System (ATLAS) spotted something unusual in galaxy 2MFGC 13525 . At first, nobody realized they were looking at a cosmic rebel. The initial classification pegged it as a different type of supernova entirely .
But a team of researchers at Kyoto University, led by Keiichi Maeda, took a closer look . What they found defied expectations.
SN 2022esa wasn't just any stellar explosion. It came from an extremely massive and luminous star—the type that should have collapsed silently into a black hole. Instead, this star went out in a blaze of glory, announcing its transformation with a brilliant supernova visible across cosmic distances .
The team used two powerful telescopes to crack the case. The 3.8-meter Seimei telescope in Okayama, Japan, provided quick classification and early observations . Meanwhile, the legendary Subaru telescope in Hawaii delivered high-sensitivity data even when the supernova had faded to less than one percent of its peak brightness .
"The fates of massive stars, the birth of a black hole, or even a black hole binary, are very important questions in astronomy. Our study provides a new direction to understand the whole evolutional history of massive stars toward the formation of black hole binaries."
— Keiichi Maeda, Lead Author
The supernova belongs to a rare class called Type Ic-CSM . These explosions show late-time narrow emission lines from elements formed deep in a massive star's core—things like oxygen and magnesium that only exist in the hearts of stellar giants .
Why Does This Supernova Pulse Like a Cosmic Clock?
Here's where the story takes an even stranger turn. When scientists analyzed the light curve—basically a record of how bright the supernova appeared over time—they discovered something astonishing.
SN 2022esa pulsed with a stable period of about 32 days .
Imagine a heartbeat in space. This supernova didn't just shine steadily; it brightened and dimmed in a regular rhythm, like cosmic breathing. The periodicity held remarkably stable across multiple observation cycles using different instruments and filters .
| Observation Band | Measured Period (days) | Uncertainty (days) |
|---|---|---|
| ATLAS o-band | 31.8 | ± 2.8 |
| ZTF r-band | 32.0 | ± 2.1 |
| ZTF g-band | 31.0 | ± 2.2 |
This kind of clockwork regularity in a supernova is incredibly rare. Before SN 2022esa, only one other supernova—SN 2022jli—had shown clear periodic modulation in its light curve . And the two events have notable differences: SN 2022jli had a shorter 12.4-day period with an asymmetric rise pattern, while SN 2022esa shows a longer period with more symmetric variations .
What causes this cosmic pulsing? The researchers traced it back to what happened before the explosion.
What's the Connection to Binary Star Systems?
The regular pulsing pointed to something profound. A single star, exploding alone, shouldn't produce such rhythmic variations. The clockwork precision required a partner .
The progenitor of SN 2022esa wasn't a lonely giant. It was locked in a gravitational dance with a companion .
The team identified the doomed star as a Wolf-Rayet star—a type of massive star that has shed its outer hydrogen and helium layers through fierce stellar winds . These are the hot, exposed cores of what were once even larger stars, burning through their fuel at staggering rates.
But what about the companion? The scientists propose two possibilities :
Option 1: A Wolf-Rayet Binary Two massive Wolf-Rayet stars orbiting each other in an eccentric (stretched ellipse) orbit. Each time they approached their closest point, gravitational interactions triggered mass ejections from the doomed star.
Option 2: A Wolf-Rayet and Black Hole Binary The companion might already have been a black hole—the remnant of an even earlier stellar death. Its gravity would periodically strip material from the Wolf-Rayet star.
| Property | Value/Description |
|---|---|
| Progenitor Type | Massive Wolf-Rayet (WR) star |
| Estimated Progenitor Mass | ~50 solar masses |
| Pre-SN Binary Orbital Period | ~1 year |
| Binary Separation | ~500 solar radii |
| Total Radiated Energy | ≥ 3 × 1050 erg |
| Host Galaxy Metallicity | ~0.4–0.5 solar |
The binary orbit wasn't circular but highly eccentric—think of a comet's elongated path around the Sun . Every time the two stars swung close together (roughly once per year before the explosion), the interaction triggered eruptions. These periodic mass ejections created shells of material surrounding the doomed star .
When the star finally exploded, the blast wave slammed into these shells. Each shell collision produced a pulse of brightness—the cosmic heartbeat we see in the light curve .
The researchers even detected hints that the period might be slowly increasing over the 200 days of observation . This makes sense: as the supernova shock wave expands and slows down, it takes longer to reach each successive shell of ejected material.
How Does This Relate to Gravitational Waves?
Here's why astronomers are so excited. The fate of the SN 2022esa system leads to one destination: a binary black hole .
If the companion was another Wolf-Rayet star, it too will eventually explode and collapse. Two black holes will remain, spiraling ever closer together over millions or billions of years.
If the companion was already a black hole, the process is even simpler. The newly formed black hole from SN 2022esa joins its partner immediately.
Either way, we're watching the birth of a gravitational wave source .
Observatories like LIGO detect gravitational waves—ripples in spacetime itself—when two black holes finally merge . These detections have opened an entirely new window on the universe since the first observation in 2015. But we've always faced a mystery: how do binary black holes form in the first place?
SN 2022esa gives us a direct glimpse into one formation channel. We're literally watching a binary black hole system being born .
When binary black holes eventually merge, they create ripples in spacetime detectable by LIGO and similar observatories. Understanding how these binaries form helps scientists interpret gravitational wave signals and trace the evolutionary history of the universe's most massive objects .
Why Does This Discovery Matter for Science?
SN 2022esa isn't just a pretty light show. It's reshaping several fields of astronomy at once.
Challenging Black Hole Formation Models
The old assumption—that the most massive stars form black holes silently—needs revision. At least some of these stellar giants announce their transformation with spectacular supernovae . This means black holes born from massive stars might leave observable signatures, opening new ways to study their formation.
Revealing Binary Star Evolution
The periodic mass loss before the explosion tells us about the final years of massive binary systems . The eccentric orbit avoided the usual circularization that happens when stars interact strongly. This suggests the progenitor lost its outer layers through powerful stellar winds rather than mass transfer to its companion.
Connecting Different Types of Supernovae
The research paper notes that SN 2022esa shares characteristics with several other unusual supernovae :
- SN 2018ibb: A candidate pair-instability supernova (the death of an extremely massive star over 100 solar masses)
- SN 2022jli: The first supernova showing clear periodic light curve modulation
- Other Type Ic-CSM supernovae: A growing class of explosions showing interaction with oxygen-rich material
These connections suggest that what we've called different types of supernovae might actually represent a spectrum of related phenomena. Binary interactions seem to play a key role across many of them .
Expanding Multi-Messenger Astronomy
The combination of optical observations (light), infrared detections (heat), and radio signals paints a complete picture . The radio emission properties (~10²⁸ erg/s/Hz at about 1.5 years) match what we see in other strongly interacting supernovae. Infrared excess in late phases suggests dusty environments—either pre-existing dust around the star or new dust forming in the explosion's aftermath .
Final Thoughts: Light Born from Darkness
We started with a simple question: what happens when the universe's biggest stars die? The old answer—silence, darkness, and immediate black hole formation—turns out to be incomplete.
SN 2022esa shows us that even stars destined to become black holes can leave with a bang. They can pulse with regular rhythms, betraying hidden companions. They can shed material in periodic eruptions for years before the final collapse. And they can create the very binary black hole systems that will someday merge and shake spacetime itself.
There's something poetic about this discovery. Stars born in brilliance, spending their lives illuminating the cosmos, were thought to end in darkness. Now we know that at least some of them refuse to go quietly. They shine one last time—bright enough to be seen across the universe, leaving a legacy written in light.
The research team combined the best of modern astronomy to crack this case. The Seimei telescope's quick response caught early details. The Subaru telescope's sensitivity revealed faint late-time emissions. Public survey data from ATLAS and ZTF filled in the gaps. Together, they transformed a mysterious flash of light into a story about stellar evolution, binary dynamics, and the birth of black holes.
As lead author Keiichi Maeda noted, understanding these events gives us new direction for tracing how massive stars evolve toward forming black hole binaries. Each new discovery adds another piece to the cosmic puzzle.
At FreeAstroScience.com, we believe knowledge should never be locked away behind complexity. The universe speaks in the language of light, gravity, and matter—and with patience, anyone can learn to listen.
Never turn off your mind. Keep it active at all times. As the saying goes, the sleep of reason breeds monsters. Stay curious, keep questioning, and remember: the cosmos is always ready to surprise us.
Come back soon for more journeys through the universe's greatest mysteries.
Sources
Thompson, M. "A Supernova That Shouldn't Exist." Universe Today, January 14, 2026.
Maeda, K., et al. "Peculiar SN Ic 2022esa: An explosion of a massive Wolf–Rayet star in a binary as a precursor to a BH–BH binary?" Publications of the Astronomical Society of Japan, December 30, 2025. https://doi.org/10.1093/pasj/psaf140
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