Neutron Stars Archives

July 28, 2022July 28, 2022 by Matt Williams

A Black Hole can Tear a Neutron Star Apart in Less Than 2 Seconds

Numerical simulation of a black hole-neutron star merger. Credit and ©: K. Hayashi (Kyoto University)

Almost seven years ago (September 14th, 2015), researchers at the Laser Interferometer Gravitational-wave Observatory (LIGO) detected gravitational waves (GWs) for the first time. Their results were shared with the world six months later and earned the discovery team the Noble Prize in Physics the following year. Since then, a total of 90 signals have been observed that were created by binary systems of two black holes, two neutron stars, or one of each. This latter scenario presents some very interesting opportunities for astronomers.

If a merger involves a black hole and neutron star, the event will produce GWs and a serious light display! Using data collected from the three black hole-neutron star mergers we’ve detected so far, a team of astrophysicists from Japan and Germany was able to model the complete process of the collision of a black hole with a neutron star, which included everything from the final orbits of the binary to the merger and post-merger phase. Their results could help inform future surveys that are sensitive enough to study mergers and GW events in much greater detail.

June 17, 2022June 17, 2022 by Matt Williams

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.

June 2, 2022June 2, 2022 by Matt Williams

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.

March 11, 2022March 11, 2022 by Brian Koberlein

Neutron Stars Could be the Best way to Measure Dark Energy

An artistic rendering of two neutron stars merging. Credit: NSF/LIGO/Sonoma State/A. Simonnet

Dark energy is central to our modern theory of cosmology. We know the universe is expanding at an ever-increasing rate, and the clearest explanation is that some kind of energy is driving it. Since this energy doesn’t emit light, we call it dark energy. But simply giving dark energy a name doesn’t mean we fully understand it. We can see what dark energy does, but its fundamental nature is perhaps the biggest scientific mystery we have.

December 14, 2021December 14, 2021 by Matt Williams

Twin Stars Prove Einstein at Least 99.99% Right

Artistic impression of the Double Pulsar system, where two active pulsars orbit each other in just 147 min. The orbital motion of these extremely dense neutrons star causes a number of relativistic effects, including the creation of ripples in spacetime known as gravitational waves. The gravitational waves carry away energy from the systems which shrinks by about 7mm per days as a result. The corresponding measurement agrees with the prediction of general relativity within 0.013%. The picture at high resolution and two alternative versions (1b, 1c) are accessible in the left column. [less] © Michael Kramer/MPIfR

More than a hundred years have passed since Einstein formalized his theory of General Relativity (GR), the geometric theory of gravitation that revolutionized our understanding of the Universe. And yet, astronomers are still subjecting it to rigorous tests, hoping to find deviations from this established theory. The reason is simple: any indication of physics beyond GR would open new windows onto the Universe and help resolve some of the deepest mysteries about the cosmos.

One of the most rigorous tests ever was recently conducted by an international team of astronomers led by Michael Kramer of the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, Germany. Using seven radio telescopes from across the world, Kramer and his colleagues observed a unique pair of pulsars for 16 years. In the process, they observed effects predicted by GR for the first time, and with an accuracy of at least 99.99%!

December 10, 2021December 10, 2021 by Nancy Atkinson

NASA Launches a New X-ray Observatory

A SpaceX Falcon 9 rocket launches with NASA’s Imaging X-ray Polarimetry Explorer (IXPE) spacecraft onboard from Launch Complex 39A, Thursday, Dec. 9, 2021, at NASA’s Kennedy Space Center in Florida. The IXPE spacecraft is the first satellite dedicated to measuring the polarization of X-rays from a variety of cosmic sources, such as black holes and neutron stars. Launch occurred at 1 a.m. EST. Credits: NASA/Joel Kowsky

A new mission has launched to study some the most intriguing secrets of the universe. No, not THAT spacecraft (JWST is scheduled for launch on December 22). Another new and exciting mission is called Imaging X-ray Polarimetry Explorer (IXPE) and it will allow scientists to explore the hidden details of some of the most extreme and high-energy objects in the cosmos, such as black holes, neutron stars, pulsars and dozens of other objects.

July 22, 2021July 22, 2021 by Andy Tomaswick

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.

July 12, 2021July 12, 2021 by Matt Williams

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

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.

July 1, 2021July 1, 2021 by Brian Koberlein

Astronomers Detected a Black Hole-Neutron Star Merger, and Then Another Just 10 Days Later

An artistic image inspired by a black hole-neutron star merger event. Credit: Carl Knox, OzGrav/Swinburne

The interior of a neutron star is perhaps the strangest state of matter in the universe. The material is squeezed so tightly that atoms collapse into a sea of nuclear material. We still aren’t sure whether nucleons maintain their integrity in this state, or whether they dissolve into quark matter. To really understand neutron star matter we need to pull it apart to see how it works and to do that takes a black hole. This is why astronomers are excited about the recent discovery of not one, but two mergers between a neutron star and a black hole.

May 12, 2021May 10, 2021 by Paul M. Sutter

How Squeezable are Neutron Stars?

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

Two neutron stars. One is 50% more massive than the other, yet they are almost exactly the same size. The results have big implications for understanding what neutron stars are really made of.