JWST Solves Decades-Old Mystery of Nearby Supernova

JWST resolves the old mystery of Decades of Supernova nearby

By Jonathan O’Callaghan Edited by Lee Billings

Almost forty years ago, residents of the earth were treated to a rare cosmic view: an explosive star in our sky which was visible to the naked eye. Called Supernova 1987a (SN 1987a), it was the event closest to the last four centuries. Since astronomers have sought to observe the stellar rest they have known must hide near the center of the supernova, wrapped in an expanding nebula of radioactive ashes and incandescent gas. Now, thanks to the power of the James Webb space telescope (JWST), a team of scientists has finally discovered this elusive career, confirming suspicions that the explosion has created an extremely dense neutron star rather than a black hole suspended by the light star.

The Discovery, published Thursday in ScienceUsed the unprecedented infrared capacities of JWST to unravel the veil surrounding SN 1987a, which allows it to be seen under a new literal light. Looking in the hearts of debris left by the disappearance of the star, the astronomers led by the Frasson Claes of the University of Stockholm in Sweden, indices of Argon and Sulfur Ionized-that is to say evidence of elements which were so shocked by an external force that their electrons had been stripped. These energized elements should not exist so close to “Ground Zero” of SN 1987A – unless they have been formed from intense ultraviolet and radiographic bombing of a nearby neutron star. A black hole fueling radiation explosions could also explain the result, but more than three decades of observations have failed to reveal other signs of such a thing in SN 1987a, which makes the result of JWST almost waterproof evidence of the existence of the neutron star.

“It’s very exciting,” said astrophysicist Mikako Matsuura of the University of Cardiff in Wales, who was not involved in the study and previously suggested in 2019 that a neutron star would be found in this supernova. “This is probably the strongest proof of the presence of a neutron star in Supernova 1987a.”

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SN 1987a exploded on February 23, 1987, in the Grand Cloud Magellanic, a dwarf satellite galaxy of the Milky Way which is around 160,000 light years from the earth. No supernova had been seen so close to our planet from the Kepler supernova in 1604, when a star exploded in our galaxy at a distance of around 20,000 light years. Although the SN 1987a was initially discovered via its sudden clarification in the sky, the first sign of the Supernova was proved from a Rafale of Neutrinos which washed the earth a few hours before the flash of light. Registered in neutrinos observatories dispersed on the planet, this burst was indicative of the formation of a neutron star somewhere in the dispersed remains of the star. The case for a neutron star grew up while a more in -depth analysis revealed that the ancestor of SN 1987a had probably been a supergiant blue star about 18 times the mass of our sun – Heavy but still too light to easily form a black hole.

The supernovae occur in two main ways: the first is when a star siphons too much material from a smaller and explodes – this results in an IA type supernova such as the Kepler Supernova. The other type of supernova – a type II supernova like SN 1987a – occurs when a very massive star which was prevented from collapsing under its own weight by the external pressure of the light which explodes of its depths suddenly lacking in fuel in its heart. Without excess stars light to support it, the outer layers of the star fall inwards, then bounce back to explode outwards, sending shock waves corrugating in the surrounding material. This process can quickly emit more light than the value of an entire stars galaxy and crushes the solar mass nucleus in an ultraded sphere the size of a city – a neutron star. In cases where the initial star was particularly heavy – 20 or more solar masses – the neutron star which results in heavier then collapses in a black hole.

Having a neutron star so relatively nearby is scientifically fascinating, explains Joanne Pledger of the University of the Central Lancashire in England, which was not involved in the study. “Physics is different on a neutron star,” she says, noting that the extreme gravitational fields of these objects tighten their entrails to create states of exotic matter and considerably deform the surrounding fabric of space-time. “If we can detect neutron stars, in particular close neutron stars that we can very well study, then we can start understanding the laws of physics in the fields that we simply cannot recreate in the laboratory.”

Although the astronomers already suspected the 1987A SN had not left a black hole, they wanted to be sure. Frasson and his colleagues saw the distinctive signs of the Argon and ionized sulfur near the center of the Supernova in July 2022, when JWST began its scientific operations for the first time. “”[SN 1987A] was one of the first objects observed, ”explains Frasson, with JWST studying the consequences of the supernova for about 10 hours.

“The only energy source capable of producing these [signs] is a neutron star, ”explains the co-author of the Patrick Kavanagh study of Maynooth University in Ireland. For a black hole to do the same, it should be delightful from the material from a source – such as another star – for which there is no evidence. “We are convinced that we have evaluated all the different possibilities”. Kavanagh.

Carefully analyzes the light emitted by the ionized material shows that the neutron star is not exactly in the middle of SN 1987a; He is rather slightly compensated because he received a “kick” from the supernova. As the star exploded, all the minor imbalances have changed more effusion material on one side or another, causing a decline in the neutron star in the opposite direction as a tight egg of a ball. The observations suggest that the neutron star moves slightly to us, after having traveled around 500 billion kilometers from the site of its cataclysmic birth. “The speed of the kick is approximately 400 kilometers per second,” says Kavanagh – without quite fast for us here on earth but still slow glacial against the immensities of light years.

What is not clear is whether the rest of SN 1987a just A neutron star. Instead, it could be a pulsar – a neutron star turning so quickly that it pulls energy streams from its posts that sweep a skiing strip like the beams of a cosmic lighthouse. “If there is a pulsar, the beam is not pointed out to us, so we cannot detect it,” explains Yvette Cendes of the Center for Astrophysics | Harvard & Smithsonian, who was not involved in the study. But there could be another way to discover it. In the scenario of standard neutron star, the pure heat of the rest stellar is so intense that it forms an ionized silicon tag which is dispersed further in the expansion cloud. In the pulsar model – where emissions are not dominated by heat but rather by winds of electrons and other particles which shock the most internal debris – ionized silicon should be rarer. So, if silicon can be identified and mapped around SN 1987a, “we can discern between the two,” explains Kavanagh. Unpublished JWST monitoring observations that were taken by the team in the fall of 2023 and earlier this week may contain this response.

These observations provide new information on the first moments after a type II supernova. “We have never seen the formation of a neutron star before,” explains Frasson. Now that we have, additional studies of this cosmically young object with JWST and other telescopes should allow astronomers to learn much more about these confusing stellar events. “Until we saw a supernova in our own galaxy, it is the best studied that we are going to have,” explains Cendes.