Neutron Star

Domain	Definitions
Physics	The imploded core of a massive star produced by a supernova explosion. (typical mass of 1.4 times the mass of the sun, radius of about 5 miles, density of a neutron.) According to astronomer and author Frank Shu, "A sugar cube of neutron-star stuff on Earth would weigh as much as all of humanity!" Neutron stars can be observed as pulsars. (references)
Space	A star (approximately sun-sized or larger), a remnant of a supernova explosion, in which gravity has caused all matter to collapse to a giant nucleus, composed only of neutrons. The collapse is also expected to greatly amplify any magnetic field present in the pre-collapse star, as well as speed up enormously any rate of rotation. It is believed that pulsars, pulsating radio sources with very precise pulsation periods, are neutron stars of radius about 10 km and rotation period about 1 second. Their magnetic axis spins and beams radio waves, in a way similar to the way a lighthouse beams its light. We detect pulsars when the Earth is in one of the directions swept by the beams. (references)
Source: compiled by the editor from various references; see credits.

Specialty Definition: Neutron star

A neutron star is the collapsed remnant of a Type II or Ib supernova. Neutron stars are typically about 20 km in diameter, have greater than 1.4 times the mass of our Sun (otherwise they'd be white dwarfs) and less than about 3 times the mass of our Sun (otherwise they'd be black holes), and spin very rapidly (one revolution can take anything from thirty seconds to a hundredth of a second). Neutron stars are the densest objects known. Due to its small size and high density, a neutron star possesses a surface gravitational field about 2×10¹¹ times that of Earth.

The matter at the surface of a neutron star is composed of ordinary nuclei as well as ionized electrons. Proceeding inward, one encounters nuclei with ever increasing numbers of neutrons; such nuclei would quickly decay on Earth, but are kept stable by tremendous pressures. Proceeding deeper, one comes to a point called neutron drip where free neutrons leak out of nuclei. In this region we have nuclei, free electrons, and free neutrons. The nuclei become smaller and smaller until the core is reached, by definition the point where they disappear altogether. The exact nature of the superdense matter in the core is still not well understood. Some researchers refer to this theoretical substance as neutronium. It could be a superfluid mixture of neutrons with a few protons and electrons, other high energy particles like pions and kaons may be present, and even sub-atomic quark matter is possible. However so far observations have not indicated nor ruled out such exotic states of matter.

Some neutron stars that can be observed:

X-ray burster - a neutron star with a low mass binary companion from which matter is accreted resulting in irregular bursts of energy from the surface of the neutron star.
Pulsar - general term for neutron stars that emit directed pulses of radiation towards us at regular intervals due to their strong magnetic fields.
Magnetar - a type of Soft gamma repeater that has a very, very strong magnetic field

Neutron stars rotate extremely rapidly after their creation due to the conservation of angular momentum; like an ice skater pulling in his arms, the slow rotation of the original star's core speeds up as it shrinks. A newborn neutron star can rotate several times a second; sometimes, when they orbit a companion star and are able to accrete matter from it, they can increase this to several thousand times per second, distorting into an oblate spheroid shape despite their own immense gravity (an equatorial bulge).

Over time, neutron stars slow down because their rotating magnetic fields radiate energy; older neutron stars may take several seconds or minutes for each revolution.

The rate at which a neutron star slows down its rotation is usually constant and very small: the observed rates are between 10^-12 and 10^-19 seconds for each century. In other words, a neutron star now rotating in 1 second will rotate in 1.000000000001 seconds after a century.

Sometimes a neutron star will undergo a glitch: a rapid and unexpected increase of its rotation speed (of the same, extremely small scale as the constant slowing down). Glitches are thought to be the effect of internal re-organizations of the matter composing the neutron star, something similar to starquakes. Such a starquake would register as grade 20 or 25 on the Richter scale.

Neutron stars also have very intense magnetic fields - about 10¹² times stronger than Earth's. Neutron stars may "pulse" due to electrons accelerated near the magnetic poles, which are not aligned with the rotation axis of the star. These electrons travel outward from the neutron star, until they reach the point at which they would be forced to travel faster than the speed of light in order to still co-rotate with the star. At this radius, the electrons must stop, and they release some of their kinetic energy in the form of X-rays and gamma-rays. External viewers see these pulses of radiation whenever the magnetic pole is visible. The pulses come at the same rate as the rotation of the neutron star, and thus, appear periodic. Neutron stars which emit such pulses are called pulsars.

When pulsars were first discovered, they were believed by some to be evidence of extra-terrestrial intelligences. Because of their highly regular pattern of emmisions, they were initially thought to be beacons of some type.

Another class of neutron star, known as the magnetar, exists. These have a magnetic field of above 10¹⁴ gauss, strong enough to wipe a credit card from the distance of the Sun away and strong enough to be fatal from the distance of the moon away. By comparison, Earth's natural magnetic field is .5 gauss, and on Earth a fatal magnetic field is only a theoretical possibility; some of the strongest fields generated are actually used in medical imaging. A small neodymium based rare earth magnet has a field of a few thousand gauss, and most media used for data storage take several hundred gauss to erase.

The processes in a magnetar involve the rotation of the neutron star tangling field lines until they become exceptionally dense, giving rise to a resonant magnetic field.

See also:

Timeline of white dwarfs, neutron stars, and supernovae

Neutron Star was a 1966 Hugo award winning short story by Larry Niven

Synonyms within Context: Neutron Star

Commercial Usage: Neutron Star

Domain	Title
Books	Neutron Star (reference) Neutron star matter : phase transition to a neutron solid? (reference) Physics of Neutron Star Interiors (Lecture Notes in Physics, 578) (reference) The Neutron Star Black Hole Connection (NATO Science Series. Series C, Mathematical and Physical Sciences, V. 567) (reference) Theory of Neutron Star Magnetospheres (Theoretical Astrophysics) (reference) (more book examples)
Source: compiled by the editor from various references; see credits.

Photo Album: Neutron Star

Frequency of Internet Keywords: Neutron Star

Modern Translations: Neutron Star

Language		Translations for "neutron star"; alternative meanings/domain in parentheses.
Dutch		neutronenster. (various references)

German		neutronenstern. (various references)

Japanese Kanji		中性子星 (a neutron star). (various references)

Japanese Katakana		ちゅうせいしせい (a neutron star). (various references)

Pig Latin		eutronnay arstay

Spanish		estrella de neutrones. (various references)
Source: compiled by the editor from various translation references.

Misspellings: Neutron Star

Anagrams: Neutron Star

Scrabble® Enable2K-Verified Anagrams
	Words within the letters "a-e-n-n-o-r-r-s-t-t-u"
	-1 letter: nonstarter.
	-2 letters: turnstone.
	-3 letters: antrorse, entrants, neutrons, outearns, outrates, outstare, resonant, rostrate, taunters, tonneaus, torrents, tortures, unornate, unreason.
	-4 letters: arenous, arouser, atoners, attorns, attunes, entrant, entrust, errants, natrons, natters, natures, neurons, neuston, neutron, nonarts, nonuser, notates, nutates, nutters, outearn, outeats, outrate, outsert, ranters, rattens, ratters, rattons, restart, retorts, returns, roaster, rotates, rotters, rouster, routers, runners, santour, saunter, senator, serrano, snorter, soutane, starter, stature, stentor, stertor, stouten, stouter, stunner, tanners, tannest, taunter, tautens, tenants, tenours, tenutos, tetanus, toaster, tonneau, tonners, tonsure, torrent, torture, tourers, touters, treason, trouser, truants, truster, trustor, turners, turnons, turrets, unstate.
	-5 letters: anenst, antres, arouse, arrest, arseno, astern, astute, atoner, atones, attorn, attune, errant, natron, natter, nature, nestor, neuron, nonart, nonets, nonuse, notate, noters, nurser, nutant, nutate, nutter, oaters, orates, ornate, ottars, otters, ouster, outate, outeat, outers, outran, outsat, outset, ranter, rarest, raster, rasure, raters, ratten, ratter, ratton, reason, reruns, resort, retorn, retort, retros, return, roster, rostra, rotate, rotten, rotter, rottes, rouens, rouser, router, routes, runner, santur, sartor, senora, setout, snarer, snorer, soarer, sonant, sonnet, sorner, sorter, sourer, souter, starer, stater, stator, statue, sterna, stoner, stoure, strunt, suntan, tanner, tarots, tarres, tarter, taster, taters, taunts, tauten, tauter, tenant, tenons, tenors, tenour, tensor, tenuto, terras, teston, tetras, toners, tonner, tonnes, torten, tortes, toters, tourer, touter, treats, tronas, trones, trouts, truant, truest, tuners, turner, turnon, turret, tutors, unrent, unrest, unseat, unsent, untorn, urares, urates, utters.
	Words containing the letters "a-e-n-n-o-r-r-s-t-t-u"
	+2 letters: renaturations.
	+3 letters: macronutrients, pretournaments.
	+4 letters: nonbarbiturates.
	+5 letters: counterarguments, counterirritants, counterreactions, countersignature, neurotransmitter, nonarchitectures.
Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro.

Context	Synonyms within Context (source: adapted from Roget's Thesaurus).
Density	Superdense matter, condensed states of matter; dwarf star, neutron star.
Source: adapted from Roget's Thesaurus.

Thumbnail	Description & Credit
	First direct look, in visible light, at a lone neutron star (RX J185635-3754). (Produced with the Wide-Field Planetary Camera 2, Hubble Space Telescope.).Credit: NASA.
Source: compiled by the editor from various references; see credits.

Expression	Frequency per Day
neutron star	76
density neutron star	4
neutron star star type	3
information neutron star	3
black hole neutron star	2
Source: compiled by the editor from various references; see credits.

Neutron Star

Definition: Neutron Star

Neutron Star

Noun

Specialty Definitions: Neutron Star

Physics

Space

Specialty Definition: Neutron star

Some neutron stars that can be observed:

Synonyms within Context: Neutron Star

Density

Crosswords: Neutron Star

Commercial Usage: Neutron Star

Books

Photo Album: Neutron Star

Frequency of Internet Keywords: Neutron Star

neutron star

density neutron star

neutron star star type

information neutron star

black hole neutron star

Modern Translations: Neutron Star

Dutch

German

Japanese Kanji

Japanese Katakana

Pig Latin

Spanish

Misspellings: Neutron Star

Misspellings

Anagrams: Neutron Star

Scrabble® Enable2K-Verified Anagrams

Alternative Orthography: Neutron Star

4E 65 75 74 72 6F 6E 53 74 61 72

01001110 01100101 01110101 01110100 01110010 01101111 01101110 00100000 01010011 01110100 01100001 01110010

&#78 &#101 &#117 &#116 &#114 &#111 &#110 &#32 &#83 &#116 &#97 &#114

004E 0065 0075 0074 0072 006F 006E 0053 0074 0061 0072

48718786848180253866784

INDEX

Misspellings
	"Neutron Star" is suggested in spellcheckers for the following: nuetron star. (additional references)
Source: compiled by the editor, based on several corpora (additional references).