Ultra-bright X-ray source awakens near a galaxy not so far away

A new ultra-bright source of X-rays has awakened in between our galactic neighbors the Magellanic Clouds, after a 26-year slumber. This is the second-closest such object known to date, with a brightness greater than a million ...

Astronomers capture a pulsar 'powering up'

A Monash-University-led collaboration has, for the first time, observed the full, 12-day process of material spiraling into a distant neutron star, triggering an X-ray outburst thousands of times brighter than our Sun.

Researchers discover a new type of matter inside neutron stars

A Finnish research group has found strong evidence for the presence of exotic quark matter inside the cores of the largest neutron stars in existence. They reached this conclusion by combining recent results from theoretical ...

Zooming in on the origins of fast radio bursts

Astronomers have peered into the home galaxies of fast radio bursts, ruling out supermassive black holes as a cause and bringing us a step closer to understanding the origins of these mysterious signals from outer space.

A single proton can make a world of difference

Scientists from the RIKEN Nishina Center for Accelerator-Based Science and collaborators have shown that knocking out a single proton from a fluorine nucleus—transforming it into a neutron-rich isotope of oxygen—can have ...

New infrared telescope to spot cosmic hidden treasures

A new infrared telescope, to be designed and built by astronomers at the Australian National University (ANU), will monitor the entire southern sky in search of new cosmic events as they take place.

Scientists puzzle over massive star system

Earlier this year, an international team of scientists announced the second detection of a gravitational-wave signal from the collision of two neutron stars. The event, called GW190425, is puzzling: The combined mass of the ...

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Neutron star

A neutron star is a type of remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and roughly the same mass as protons. Neutron stars are very hot and are supported against further collapse because of the Pauli exclusion principle. This principle states that no two neutrons (or any other fermionic particle) can occupy the same quantum state simultaneously.

A typical neutron star has a mass between 1.35 and about 2.1 solar masses, with a corresponding radius of about 12 km if the Akmal-Pandharipande-Ravenhall (APR) Equation of state (EOS) is used. In contrast, the Sun's radius is about 60,000 times that. Neutron stars have overall densities predicted by the APR EOS of 3.7 to 5.9 × 1017 kg/m³ (2.6 to 4.1 × 1014 times Solar density), which compares with the approximate density of an atomic nucleus of 3 × 1017 kg/m³. The neutron star's density varies from below 1 × 109 kg/m³ in the crust increasing with depth to above 6 or 8 × 1017 kg/m³ deeper inside.. This is approximately the weight of the entire human population condensed into the size of a sugar cube.

In general, compact stars of less than 1.44 solar masses, the Chandrasekhar limit, are white dwarfs; above 2 to 3 solar masses (the Tolman-Oppenheimer-Volkoff limit), a quark star might be created, however this is uncertain. Gravitational collapse will always occur on any star over 5 solar masses, inevitably producing a black hole.

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