The Neutron Star That Thinks It’s a Black Hole

Artist's impression of the blazing eruption of the neutron star Swift J1858 compared to the black hole GRS 1915+105. Credit: Gabriel Pérez Díaz (IAC)
Artist's impression of the blazing eruption of the neutron star Swift J1858 compared to the black hole GRS 1915+105. Credit: Gabriel Pérez Díaz (IAC)

Black holes and neutron stars are among the odder denizens of the cosmic zoo. They’re both dense collections of matter and, except for supermassive black holes, are the end states of massive stars. Fundamentally, they’re two different types of objects that are detectable via the activity in the accretion disks that form around them. Astronomers recently observed an object that acted like a black hole but turned out to be a neutron star. The clues lay in the accretion disk surrounding it.

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Astronomers Go Hunting for Mysterious Q-balls

A false-color image of the Smith Cloud made with data from the Green Bank Telescope (GBT). New analysis indicates that it is wrapped in a dark matter halo. Credit: NRAO/AUI/NSF

Our universe may feature large, macroscopic clumps of dark matter, known as q-balls. These q-balls would be absolutely invisible, but they may reveal their presence through tiny magnifications of starlight.

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Some Elements Arrived on Earth by Surfing Supernova Shock Waves

Neutron-neutron star mergers are one way that heavy radioactive isotopes of elements found on Earth could be created. Courtesy ESO.
Neutron-neutron star mergers are one way that heavy radioactive isotopes of elements found on Earth could be created. Courtesy ESO.

When stars die, they spread the elements they’ve created in their cores out to space. But, other objects and processes in space also create elements. Eventually, that “star stuff” scatters across the galaxy in giant debris clouds. Later on—sometimes millions of years later—it settles onto planets. What’s the missing link between element creation and deposition on some distant world?

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Magnetars are Extreme in Every Way, Even Their Volcanoes

Artist rendition of a magnetar eruption. These could be source of fast radio bursts. (Credit: NASA Goddard Space Flight Center)
Artist rendition of a magnetar eruption. These could be source of fast radio bursts. (Credit: NASA Goddard Space Flight Center)

In a recent study published in Nature Astronomy, an international team of researchers led by NASA and The George Washington University examined data from an October 2020 detection of what’s known as a “large spin-down glitch event”, also known as an “anti-glitch”, from a type of neutron star known as a magnetar called SGR 1935+2154 and located approximately 30,000 light-years from Earth, with SGR standing for soft gamma repeaters. Such events occur when the magnetar experiences a sudden decrease in its rotation rate, which in this case was followed by three types of radio bursts known as extragalactic fast radio bursts (FRBs) and then pulsed radio emissions for one month straight after the initial rotation rate decrease.

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Astronomers use Earthquakes to Understand Glitches on Neutron Stars

Simulation of a possible quadrupole magnetic field configuration for a pulsar with hot spots in only the southern hemisphere. Credits: NASA's Goddard Space Flight Center

A team of astronomers have used a model of earthquakes to understand glitches in the timing of pulsars. Their results suggest that pulsars may have interiors that are far stranger than can be imagined.

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Colliding Neutron Stars can Generate Long Gamma-ray Bursts

Artist's illustration of a bright gamma-ray burst occurring in a star-forming region and beaming out energy into two narrow, oppositely directed jets. Image Credit: By NASA/Swift/Mary Pat Hrybyk-Keith and John Jones - http://imagine.gsfc.nasa.gov/docs/features/news/10sep08.html [1]Transferred from en.wikipedia to Commons by TheDJ using CommonsHelper., Public Domain, https://commons.wikimedia.org/w/index.php?curid=8807284

Gamma-Ray Bursts (GRBs) are the most energetic recurring events in the Universe. Only the Big Bang was more energetic, and it was a singularity. Astronomers see GRBs in distant Universes, and a lot of research has gone into understanding them and what causes them.

A new paper is upending some of what scientists thought they knew about these extraordinary explosions.

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New Observations Confirm That a Magnetar has a Solid Surface and No Atmosphere

An artist's impression of a magnetar, a highly magnetic, slowly rotating neutron star. Credit: ESO/L. Calçada

Can a star have a solid surface? It might sound counterintuitive. But human intuition is a response to our evolution on Earth, where up is up, down is down, and there are three states of matter. Intuition fails when it confronts the cosmos.

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The Smallest, Lightest Neutron Star Ever Seen Could be a “Strange Star”

The supernova remnant HESS J1731-347 surrounding a small neutron star. Credit: Victor Doroshenko

The life of every star is a fight against gravity. Stars are so massive they risk collapsing under their own weight, but this is balanced by the heat and pressure a star generates through nuclear fusion. Eventually, that comes to an end. The outer layers of a star will be cast off, and the remaining core will become a stellar remnant. Which kind of remnant depends on the mass of the core.

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The Heaviest Neutron Star Ever Seen Got There by Feasting on its Companion

Life’s not too good if you’re the companion of a black widow. Here on Earth, spiders by that name feast on their smaller significant others after mating. Out in space, some weird objects do the same thing to their closeby neighbors. They’re rapidly spinning neutron stars that slowly destroy their companion stars with powerful outflows of high-energy particles. A team at the University of California Berkeley is studying one of these so-called “black widow pulsars”, called PSR J0952-0607. Thanks to its hefty appetite, it shredded and consumed nearly all of its stellar companion. That eating spree made it the heaviest known neutron star to date.

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