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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A new Record for the Strongest Magnetic Field Seen in the Universe: 1.6 Billion Tesla

A massive flare ejected from a magnetar.

A team of astronomers using the Chinese Insight-HXMT x-ray telescope have made a direct measurement of the strongest magnetic field in the known universe. The magnetic field belongs to a magnetar currently in the process of cannibalizing an orbiting companion.

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The Case is Building That Colliding Neutron Stars Create Magnetars

Magnetars are some of the most fascinating astronomical objects. One teaspoon of the stuff they are made out of would weigh almost one billion tons, and they have magnetic fields that are hundreds of millions of times more powerful than any magnetic that exists today on Earth. But we don’t know much about how they form. A new paper points to one possible source – mergers of neutron stars.

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A Rare Repeating Fast Radio Burst Gives Astronomers a Chance to Study These Mysterious Objects

Fast Radio Bursts (FRBs) are among the most mysterious astronomical phenomena facing astronomers today. While hundreds of bursts have been detected since the first-ever recorded detection of an FRB in 2007 – the Lorimer Burst – astronomers are still unsure what causes them. Even more mysterious, some have occasionally been found to be repeating in nature, which has fueled speculation that they may not be natural in origin (i.e., possible alien transmissions?). Astronomers are naturally very excited whenever a repeating FRB is found, as it gives them the chance to examine them closer.

In a recent survey, an international team of scientists used three major telescopes worldwide to study a repeating FRB (known as FRB 190520) that was first observed in 2019. According to their observations, this particular FRB is not just a repeating source from a compact object but a persistent one that emits low-level bursts of radio waves between larger ones. These findings raise new questions about the nature of these mysterious objects and how they can be used as tools to probe the space between stars and galaxies.

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A Pulsar has Been Found Turning so Slowly Astronomers Didn't Even Think it was Possible: Once Every 76 Seconds

Astronomy is progressing rapidly these days, thanks in part to how advances in one area can contribute to progress in another. For instance, improved optics, instruments, and data processing methods have allowed astronomers to push the boundaries of optical and infrared to gravitational wave (GW) astronomy. Radio astronomy is also advancing considerably thanks to arrays like the MeerKAT radio telescope in South Africa, which will join with observatories in Australia in the near future to create the Square Kilometer Array (SKA).

In particular, radio astronomers are using next-generation instruments to study phenomena like Fast Radio Bursts (FRBs) and neutron stars. Recently, an international team of scientists led by the University of Manchester discovered a strange radio-emitting neutron star with a powerful magnetic field (a “magnetar”) and an extremely slow rotational period of 76 seconds. This discovery could have significant implications for radio astronomy and hints at a possible connection between different types of neutron stars and FRBs.

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Pulsars Could Explain the Excess of Gamma Radiation Coming from the Center of the Milky Way

A gamma-ray view of the sky centered on the core of the Milky Way Galaxy. Could strange spinning neutron stars explain an excess of gamma-radiation emanating from the Milky Way's core region? That's one possibility astronomers are discussing. Courtesy NASA/DOE/Fermi LAT Collaboration
A gamma-ray view of the sky centered on the core of the Milky Way Galaxy. Could strange spinning neutron stars explain a mysterious excess of gamma radiation emanating from the core region? That’s one possibility astronomers are discussing. Courtesy NASA/DOE/Fermi LAT Collaboration

Ever hear of the Galactic Center GeV Excess? No, it’s not a cosmic rock band, although that’s a great name for one. Actually, it’s what astronomers call a super-high rate of gamma-ray radiation coming from the heart of our Milky Way Galaxy. Since this Galactic Center Excess was first detected in 2009, people thought it might be a signature of dark matter annihilating itself in mass quantities. But, as with any unexplained phenomenon in space, others disagreed. It could also have something to do with Sagittarius A*, the galaxy core’s own supermassive black hole. Or, it might be some other kind of strange burst event. Now, an astronomer at the Australian National University suggests that rapidly spinning neutron stars may be the culprits behind this high-energy galactic mystery.

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The Expanding Debris Cloud From the Kilonova Tells the Story of What Happens When Neutron Stars Collide

This artist’s conception illustrates the aftermath of a "kilonova," a powerful event that happens when two neutron stars merge. The object is called GW170817 and is the only cosmic event where both gravitational waves and electromagnetic radiation were detected. Image Credit: X-ray: NASA/CXC/Northwestern Univ./A. Hajela et al.; Illustration: NASA/CXC/M.Weiss

When two neutron stars collide, it creates a kilonova. The event causes both gravitational waves and emissions of electromagnetic energy. In 2017 the LIGO-Virgo gravitational-wave observatories detected a merger of two neutron stars about 130 million light-years away in the galaxy NGC 4993. The merger is called GW170817, and it remains the only cosmic event observed in both gravitational waves and electromagnetic radiation.

Astronomers have watched the expanding debris cloud from the kilonova for years. A clearer picture of what happens in the aftermath is emerging.

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