The mystery of the famous supernova explosion: Astronomers finally see the true face of the mysterious celestial body 170,000 light-years away

The evolution and fate of stars are closely related to their mass. The mass of stars is generally measured by the mass of the sun, which is about 2*10^30kg. The modern standard model of the universe believes that supernovae will occur in the late stages of the evolution of medium and large stars, eventually leaving a dense celestial body in the core.

Stars with the mass of the sun are only considered small stars in the universe. They will not explode as a supernova at the end of their evolution, and their cores will collapse into white dwarfs. Stars with a mass of more than 8 times that of the sun will explode as a supernova when they die. Stars with a mass of less than 30 times that of the sun may leave a neutron star in their core after a supernova explosion; and stars with a mass of more than 30 times that of the sun may leave a black hole.

White dwarfs, neutron stars, and black holes are all highly dense celestial bodies, and each is smaller and more massive than the other, so the density is also getting higher and higher. A white dwarf is only the size of the Earth, but its mass is 0.5 to 1.4 times that of the Sun, and its density can reach 1 to 10 tons per cubic centimeter; a neutron star has a diameter of only 10 to 30 kilometers, and its density is as high as 100 million to 1 billion tons per cubic centimeter; the core of a black hole is an infinitely small singularity, so its density is infinitely large, and the mass of a newly generated seed black hole is about 3 to 10 times that of the Sun.

At first, these were theoretical conjectures based on gravitational field theory. With the improvement of space observation, it was discovered that white dwarfs, neutron stars, black holes and other strange celestial bodies really exist in the universe, and more and more of them are discovered. They are ubiquitous celestial bodies. But there is no evidence that these celestial bodies really appeared after supernova explosions.

Recently, the most powerful Webb telescope to date and its predecessor, the Hubble telescope, have solved the mystery of the core of this most famous supernova in history by observing supernova 1987A and combining the observation photos and data, confirming that there is indeed a neutron star at its center.

Supernova 1987A is an explosion that occurred in the center of the Large Magellanic Cloud, a satellite galaxy of the Milky Way, about 160,000 light-years away. In other words, the light from the supernova explosion traveled for 160,000 years before reaching Earth in February 1987 and being captured by telescopes.

This is the closest and brightest supernova observed by humans since 1604. For 37 years, scientists have been studying this supernova, but they cannot figure out whether there is a dense celestial body in the core. According to the observed neutrino waves, it may have produced a neutron star with a diameter of about 20 kilometers, but it is difficult to draw a reliable conclusion based on these clues alone, and various possibilities have been under discussion.

The most powerful space telescope to date, James Webb, was launched in 2021, greatly improving human observation methods. New discoveries in the deep space continue to surprise people and add chips to the study of the 1987A supernova. The Webb telescope can observe electromagnetic waves in different bands and has a higher resolution than its predecessors. In July 2022, the Webb telescope observed 1987A for 9 hours and made a breakthrough discovery.

Observations by the Webb telescope discovered that the core of supernova 1987A has ionized argon and sulfur gases. These gases can only be triggered by neutron stars and are evidence that these atoms were ionized by neutron star radiation. They can therefore be regarded as the "fingerprint" of the existence of neutron stars. It can be determined that this is the strongest evidence to date that there is a neutron star at the core of supernova 1987A.

Neutron stars are so small that they are only equivalent to a small city on Earth, and are just a speck of dust in space. The closest neutron stars discovered so far are hundreds of light years away from Earth, so they have not been directly observed so far. However, squid neutron stars have their own unique characteristics, especially their powerful electromagnetic radiation that sweeps across space like a lighthouse. When it sweeps past the Earth, it will be captured by radio telescopes, and thousands of neutron stars have been discovered.

After a supernova explodes, the core is obscured by dust, so it is difficult to see the core with ordinary telescopes. The infrared band observations of the Webb telescope can penetrate the fog and see the truth, thus solving the mystery of scientists' observations for decades. Patrick Kavanagh, an astrophysicist at Maynooth University in Ireland, said: "This is what we have been looking for since the explosion, and now we have found it."

The research was published in the world-renowned journal Science. Josefin Larsson, an astrophysicist at the KTH Royal Institute of Technology in Stockholm and a member of the research team, said: "The data quality is very high, much better than I expected." Another astrophysicist, Mikako Matsuura, said: "JWST (Webb Telescope) is really an amazing telescope that can provide such discoveries."

The significance of this discovery is very significant. It proves that true scientific theories can stand the test of practice and time. The vast universe and the vast starry sky contain countless wonders and secrets. Scientific theories also predict many things that have not yet been confirmed, such as white holes, wormholes, etc.

Of course, the evidence of this discovery is still indirect, and no telescope has seen the true appearance of the neutron star at the core of 1987A so far. But as the supernova continues to expand, the dust blocking the core will become thinner and thinner and dissipate. Scientists are sure that the neutron star at the core will eventually be exposed, and more and more clues will be obtained from observations. Let us look forward to it.

Thanks for reading, and welcome to discuss.

This is an original article from Space-Time Communication. Please respect the author’s copyright. Thank you for your understanding and cooperation.

Reference link: https://www.nature.com/articles/d41586-024-00528-4?utm_source=Live+Audience&utm_campaign=d9ad4e8e7d-briefing-dy-20240226&utm_medium=email&utm_term=0_b27a691814-d9ad4e8e7d-51426400