SN 1987A is the only supernova visible to the naked eye in the past 400 years and the most studied supernova in history. This event was a nuclear collapse supernova, meaning that the compressed remains of its core formed either a neutron star or a black hole. Evidence for such compact objects has long been sought, and while indirect evidence for the existence of neutron stars has been found before, most likely the effects of high-energy emissions from young neutron stars have not been detected. This is the first time I have done so.

SN 1987A was first observed on February 23, 1987 at the edge of the Large Magellanic Cloud, about 163,000 light-years away.

This was the first supernova to be observed with the naked eye since Johannes Kepler witnessed one more than 400 years ago.

About two hours before the first visible light observation of SN 1987A, three observatories around the world detected a burst of neutrinos that lasted just a few seconds.

The two different types of observations were associated with the same supernova event and provided important evidence that informs theories about how nuclear collapse supernovae occur.

This theory included the expectation that supernovae of this type would form neutron stars or black holes.

Since then, astronomers have been searching for evidence of these compact objects at the center of expanding debris.

Indirect evidence for the presence of neutron stars at the center of remnants has been discovered in recent years, with observations of much older supernova remnants such as the Crab Nebula showing that neutron stars have been found in many supernova remnants. has been confirmed.

However, until now no direct evidence of neutron star formation in the aftermath of SN 1987A has been observed.

“Theoretical models of SN 1987A suggest that the 10-second burst of neutrinos observed just before the supernova explosion led to the formation of a neutron star or black hole,” said lead author of the study. said Claes Fransson, an astronomer at Stockholm University.

“However, no convincing signs of such a newborn object due to a supernova explosion have been observed.”

“With this observatory, we found direct evidence of ejection caused by a newborn compact object, likely a neutron star.”

In the study, Dr. Franson et al. mm and NIR spec Instruments on NASA/ESA/CSA's James Webb Space Telescope observed SN 1987A at infrared wavelengths, showing that a heavy mass whose outer electrons have been stripped (i.e., atoms have become ionized) near where the star exploded occurred. They found evidence of argon and sulfur atoms. .

They modeled a variety of scenarios in which these atoms could be driven solely by ultraviolet or They discovered that it could have been ionized only by the wind. (Pulsar wind nebula).

If the former scenario were true, the neutron star's surface would be about 1 million degrees Celsius, cooling from about 100 billion degrees Celsius at the moment it formed at its collapse center more than 30 years ago.

Professor Mike Barlow of University College London said: “The detection of strong ionizing argon and sulfur emission lines from the very center of the nebula surrounding SN1987A using Webb's MIRI and NIRSpec spectrometers suggests a central source of ionizing radiation. This is direct evidence of the existence of .

“Our data can only match neutron stars as the power source of ionizing radiation.”

“This radiation is not only emitted from the multi-million-degree surface of a hot neutron star, but also from the pulsar winds that may be produced when a neutron star spins rapidly, dragging charged particles around it. It can also be emitted from nebulae.”

“The mystery surrounding whether neutron stars are hidden in dust has been going on for more than 30 years, so we are very happy to have solved it.”

“Supernovae are the main source of the chemical elements that make life possible, so we want to accurately derive the supernova model.”

“No other object like the neutron star SN 1987A is so close to us and formed so recently. The surrounding material is expanding, so we'll see more of it over time. It will be.”

“It was clear that there had to be a high-energy radiation source at the center of the SN 1987A debris to produce the ions observed in the ejecta,” Dr. Franson said.

“The paper discusses a variety of possibilities, but we found that only a few scenarios are likely, and all of them involve newly formed neutron stars.”

of paper Published in the February 22, 2024 edition of the Journal science.

_____

C. Franson other. 2024. Emission lines from ionizing radiation from a compact object in the remains of supernova 1987A. science 383 (6685): 898-903; doi: 10.1126/science.adj5796