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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Astronomers Discover a Mysterious Star That Flashes Every 20 Minutes. But What is it?

A radio map of the Milky Way showing the location of the new transient. Credit: Dr Natasha Hurley-Walker (ICRAR/Curtin) and the GLEAM Team

Just 4,000 light-years from Earth is a strange, star-sized object. It’s been observed by radio telescopes, but astronomers aren’t sure what it is. They call it a long period transient.

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Neutron Stars Have Mountains, They’re Just a Fraction of a Millimeter High

The universe has some very extreme places in it – and there are few places more extreme than the surface of a neutron star.  These ultradense objects form after a supergiant star collapses into a sphere about 10 kilometers (6 miles) in diameter.  Their surface is extreme because of the gravity, which is about a billion times stronger than Earth. However, that gravity also forces the stellar remnant to be extraordinarily flat.  Just how flat is the outcome of a new set of theoretical research by PhD student Fabian Gittins from the University of Southampton. 

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A Nearby White Dwarf Might be About to Collapse Into a Neutron Star

Credit: Giuseppe Parisi

About 97% of all stars in our Universe are destined to end their lives as white dwarf stars, which represents the final stage in their evolution. Like neutron stars, white dwarfs form after stars have exhausted their nuclear fuel and undergo gravitational collapse, shedding their outer layers to become super-compact stellar remnants. This will be the fate of our Sun billions of years from now, which will swell up to become a red giant before losing its outer layers.

Unlike neutron stars, which result from more massive stars, white dwarfs were once about eight times the mass of our Sun or lighter. For scientists, the density and gravitational force of these objects is an opportunity to study the laws of physics under some of the most extreme conditions imaginable. According to new research led by researchers from Caltech, one such object has been found that is both the smallest and most massive white dwarf ever seen.

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A new way to see Inside Neutron Stars

The song of a binary tells us about neutron stars. Credit: University of Bath

Imagine trying to study an object light-years away that is less than 20 kilometers in diameter. The object is so dense that it’s made of material that can’t exist naturally on Earth. This is the challenge astronomers face when studying neutron stars, so they have to devise ingenious ways to do it. Recently a team figured out how to study them by using the power of resonance.

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Astronomers think they’ve seen a magnetar form for the first time; the collision of two neutron stars

Artist view of a kilonova producing a magnetar. Credit: NASA, ESA, and D. Player (STScI)

A magnetar is a neutron star with a magnetic field thousands of times more powerful than those of typical neutron stars. Their fields are so strong that they can generate powerful, short-duration events such as soft gamma repeaters and fast radio bursts. While we have learned quite a bit about magnetars in recent years, we still don’t understand how neutron stars can form such intense magnetic fields. But that could soon change thanks to a new study.

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