Recent observations have revealed a fascinating phenomenon: a star that quietly collapsed into a black hole without the dramatic supernova explosion typically associated with such an event. This discovery challenges our understanding of stellar evolution and opens new avenues for research into the formation of black holes.
The Silent Giant
The star in question, known as N6946-BH1, is located in the Fireworks Galaxy, about 22 million light-years away. In 2009, astronomers noticed that the star began to dim and eventually disappeared from view altogether. Initially, they suspected a supernova, but further observations revealed no signs of an explosion. Instead, the star simply vanished, leaving behind a compact object with a mass of about 20 times that of the Sun.
This observation suggests that N6946-BH1 collapsed directly into a black hole without expelling any material. This process, known as a failed supernova, is thought to be rare and difficult to detect. However, it is possible that many other stars may have undergone this fate without being observed.
Implications for Stellar Evolution
The discovery of N6946-BH1 has significant implications for our understanding of stellar evolution. It suggests that there are multiple pathways by which massive stars can end their lives. Some stars may explode in a supernova, while others may collapse directly into a black hole without any visible outburst.
This finding also has implications for the formation of black holes. It suggests that black holes can form over a wider range of masses than previously thought. This could help to explain the existence of supermassive black holes, which are found at the centers of many galaxies.
Future Research
The discovery of N6946-BH1 opens up new avenues for research into the formation of black holes. Astronomers are now looking for other examples of stars that may have collapsed directly into black holes without a supernova. They are also using computer simulations to study the physics of this process.
The study of silent giants like N6946-BH1 is helping us to better understand the complex and fascinating lives of stars. It is also helping us to unravel the mysteries of black holes, some of the most powerful and enigmatic objects in the universe.

Observations of VFTS 243 provide evidence that black holes can form directly from the collapse of massive stars, without a preceding supernova explosion.

A newly discovered binary star system, combined with cutting-edge models of stellar collapse, has shed light on how stellar-mass black holes form. An international team of researchers from the Max Planck Institute for Astrophysics and the Niels Bohr Institute (NBI) at the University of Copenhagen has found evidence that massive black holes can form without the dramatic supernova explosions traditionally associated with star death. Instead, the energy from the collapse is primarily carried away by lightweight neutrino particles, with minimal asymmetry. This results in only a small “natal kick” for the newly formed black hole.

Black Hole Binary Systems

For years, astronomers have known about binary star systems in the Milky Way where one star is paired with a black hole. “The discovery of black-hole binary VFTS 243 in our neighboring Large Magellanic Cloud was extraordinary, and the system itself is remarkable,” says Alejandro Vigna-Gómez, formerly a postdoctoral researcher at the Niels Bohr Institute (NBI) and now at the Max Planck Institute for Astrophysics (MPA). VFTS 243 consists of a massive star, 25 times the Sun’s mass, paired with a black hole about 10 times the Sun’s mass.

Supernova Explosions and Their Impact

Stars that are several times more massive than the Sun often end their lives in dramatic explosions called supernovae. During these events, the dense metal core of the star collapses, releasing immense energy, mostly in the form of neutrinos. The star’s outer layers are then violently ejected into space at speeds of hundreds to thousands of kilometers per second. This expelled material, which can equal several times the Sun’s mass, creates large-scale asymmetries in the explosion remnants, observable even long after the supernova occurs.

Exploring Black Hole Formation Without Explosions

The recent discovery of “disappearing” stars suggests that a large fraction of collapsing massive stars form black holes without any explosion, which unlike the bright supernovae we cannot observe. However, it is unclear how much mass these stars lose during black hole formation, or how large their natal kicks are. If the massive star directly collapses into a black hole, no baryonic matter is ejected, and energy is predominantly lost via neutrinos. “VFTS 243 has allowed us to test this scenario,” says Vigna-Gómez.

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