The James Webb Space Telescope detects violent collisions between neutron stars

Using the James Webb Space Telescope (JWST), astronomers have traced an incredibly bright gamma-ray burst (GRB) back to its source, a violent collision between two neutron stars.

The ring on her finger likely contains atoms forged in neutron star collisions like this one, also known as “kilonova.” This is because, in addition to detonating long-lived GRBs, kilonovas are believed to be the sites where the universe’s heaviest elements, which cannot be synthesized in the nuclear furnaces at the heart of stars, are forged.

These elements are theorized to be created by a mechanism called “neutron capture” or r-process, which allows atomic nuclei to capture neutrons, creating new, heavier elements, including gold, platinum, and uranium. The r-process can proceed only under extreme and violent conditions, such as those found around colliding neutron stars.

Related: Surprise! The colliding neutron stars create perfectly spherical “kilonova” explosions

This is the first time JWST has been used to detect emissions from such an event, and the powerful space telescope was also able to detect the signature of heavy elements forged in the explosive event. In particular, the team saw evidence of the heavy element tellurium and the creation of the lanthanides, a group of 15 metals heavier than lead.

“These observations demonstrate that nucleosynthesis in GRBs can create r-process elements over a broad atomic mass range and play a central role in the nucleosynthesis of heavy elements throughout the universe,” the team wrote in a paper detailing their findings. discoveries.

The GRB followed to its kilonova source by the team led by Andrew Levan, a professor at Radboud University in the Netherlands, is also extraordinary in its own right. Designated GRB 230307A, it was initially detected by NASA’s Fermi Gamma-ray Space Telescope on March 7, 2023, and is the second-brightest GRB ever seen.

The GRB lasted about 34 seconds and was spotted by many other telescopes, which is what allowed it to be triangulated to its source by astronomers. Team member Brian Metzger, of Columbia University, discussed the result in a series of tweets Thursday (July 6).

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“In Andrew Levan’s work, we detected kilonova emission (for the first time!) with JWST, after a GRB,” Metzger wrote. “Perhaps in the biggest twist: the GRB, the second-brightest of all time, lasted for half a minute, or a ‘long’ second flash accompanied by r-process production. Probably a neutron star merger, but which challenges our ideas about how long the central engine should ‘throw'”.

JWST observed the kilonova twice, first at 29 days after the GRB and then again at 61 days after the radiation outburst, with the rapid fade in brightness and blue-to-red transition between these observations suggesting its nature of kilonovas.

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The team identified several bright galaxies in the kilonova’s vicinity that could be the site of this neutron star collision and, thus, the source of GRB 230307A. They prefer the brightest of these galaxies, which are about 8.3 million light-years from Earth and offset from the GRB’s source by about 130,000 light-years.

The kilonova could also have been detected in another type of emission other than light. Colliding neutron stars cause the very fabric of spacetime to “sound” in the form of gravitational waves. These ripples can be detected here on Earth by detectors like the Laser Interferometer Gravitational-Wave Observatory, but LIGO was not active when GRB 230307A ignited. The facility was in the midst of a three-year shutdown at the time, receiving updates to make it more responsive, only coming back online in May 2023.

It is still early days for the team’s discovery, which is currently undergoing peer review before publication in a journal. A first version of the paper, which may be subject to revision, is published on the arXiv research repository.