Mysterious eruption found on star could help explain fast radio bursts
(ORDO NEWS) — One of the most interesting stars in the Milky Way is still generating more interest than it needs to.
In October 2020, SGR 1935+2154 is the magnetar responsible for transmitting radio signals. before being discovered in our home galaxy, has suddenly slowed down.
Scientists now believe that the slowdown in rotation may be evidence of a volcanic eruption on its surface, spewing matter into space, which has changed the environment of the star enough to slow the planet’s rotation by a minute.
This discovery may shed light on the mystery of fast radio bursts – how these super-dense dead stars can spew powerful staccato radio bursts for millions of light-years.
“People have speculated that neutron stars might have volcanoes on their surface,” says astrophysicist Matthew Baring of Rice University in Houston, Texas.
“Our results indicate that this could be the case, and that in this case the rupture most likely occurred at the ar magnetic pole of the star.”
SGR 1935+2154 burst onto the world stage – literally – in May 2020, when astronomers discovered that it was emitting a short but powerful radio flare.
The reason this was interesting was that we had previously only detected flashes like this in other galaxies.
These flares, which occur in the radio range, have a duration of only a millisecond and radiate as much energy during this time as 500 million Suns.
And most of them flared up one day, unexpectedly, and since then no one noticed them.
Due to the distance and unpredictability of these fast radio bursts, it is very difficult to know more about these fast radio bursts.
Astronomers have been able to trace some of them back to the galaxies that emitted them, but figuring out the mechanism or mechanisms behind them has been much more difficult.
SGR 1935+2154 was a breakthrough: now, finally, we could trace a fast radio burst to a specific object.
SGR 1935+2154 is a type of neutron star known as a magnetar.
Neutron stars are already extreme: the ultra-dense cores of massive stars that have gone supernova, tearing off their outer material, while the remaining heart of the star collapses under gravity into a sphere packing a mass of about 2.4 Suns about 20 kilometers in diameter ( 12 miles).
Add in an insanely powerful magnetic field, about 1,000 times more powerful than a typical neutron star and a quadrillion times more powerful than Earth‘s, and you have a magnetar.
Astronomers have speculated that the outward pull of this magnetic field against the inward gravity pressure could cause the magnetar to occasionally break apart, p causing flares and fast radio bursts.
But more information was needed, so SGR 1935+2154 remained under close surveillance. Then, in October 2020, it was caught again, emitting millisecond radio signals.
And now a research team led by astrophysicist George Younes of George Washington University has discovered that just a few days before this activity, he did something really strange: he suddenly slowed down.
Sometimes neutron stars suddenly changed their rotation speed. This is called a glitch and is a poorly understood phenomenon.
The failure of a neutron star is usually a sudden acceleration in the rate of rotation. Slowdown, sometimes referred to as anti-glitch, is much less common.
Only three anti-glitches have been found, including SGR 1935+2154. And if the glitch can be explained by changes within the star, then the anti-glitch cannot.
So the researchers set out to find out what could have caused it and what the role, if any, of the anti-glitch is. Gluck may have played a role in the generation of radio burst activity detected a few days later.
If internal changes could not be the cause of the slowdown, the researchers turned to external explanations.
They built a model based on a volcanic rupture on the surface of a magnetar that ejects a wind of particles into space around the star, postulating that the rarity of both events anti-glitch and radioactivity means that their temporal proximity implies a relationship.
“What makes the October 2020 event unique is that just a few days after the anti-glitch, there was a fast radio burst from the magnetar, as well as the inclusion of a pulsed, ephemeral radio emission shortly after,” says Baring.
“We saw only a few short-term pulsed radio emissions. gnetars, and this is the first time we’ve seen a magnetar radio-on almost at the same time as the anti-glitch.”
And, according to their model, a gap near the stellar pole could create a wind that interacts with the magnetar’s magnetic field, slowing the star’s rotation rate and changing the geometry of the magnetic field in such a way as to improve conditions for radio emission.
Powerful, the team found that a massive wind blowing for just a few hours from a volcano-like location could create the conditions necessary for slowing down and subsequent radioactive activity.
“The interpretation of the wind provides a way to understand why the radio emission is turned on,” says Baring.
“It gives a new understanding that we didn’t have before.”
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