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Protostar

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Protostar
The formation of stars begins with the collapse and fragmentation of molecular clouds into very dense clumps. These clumps initially contain ~0.



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A . A is a star in the very earliest stage of development, when interstellar gas is still undergoing gravitational collapse, and nuclear fusion at the core has just begun.

Definition: protostar: Very dense regions (or cores) of molecular clouds where stars are in the process of forming.
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Wikipedia, the free encyclopedia - Cite This Source
A is an object that forms by contraction out of the gas of a giant molecular cloud in the interstellar medium.

Protostar
A protostar is a cloud of hot, dense gas and dust that is gravitationally collapsing to form a star.
Pulsar
A pulsar is a rapidly spinning neutron star that emits energy in pulses.

s and Planets IV (V. Manings Ed.)
April 19, 2005 MAYOR M., QUELOZ D., BEUZIT J.-L., MARIOTTI J.-M., NAEF D., PERRIER C. & SIVAN J.-P.

Protostars
Protostars form when sections of giant molecular clouds start to collapse. Clouds are initially diffuse enough that they do not contract unless something triggers an increase in the density of some regions within a cloud.


A star in its earliest stages of formation.
pulsar
A pulsating radio source thought to be associated with a rapidly rotating neutron star.

protostar
The initial stage of stellar formation. A protostar generates energy but its core is not hot enough to ignite nuclear fusion.


Very dense regions (or cores) of molecular clouds where stars are in the process of forming.

Protostar
A collapsing cloud of gas and dust destined to become a star.
Pulsar ...

: A star in the process of formation which has not yet become hot enough in the core to initiate the process of nuclear fusion (107 K) to halt its gravitational collapse.

PROTOSTAR
A star in the process of being born from an interstellar gas cloud.
PULSAR ...



A is a star that is still forming and nuclear fusion has not yet begun.
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Protostar- a stage in the formation of a star which implies the body is nearly full-size; the star is still within its parent nebula, and does not yet produce energy through nuclear fusion ...

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The contracting cloud heats up due to friction and forms a glowing ; this stage lasts for roughly 50 million years. If there is enough material in the , the gravitational collapse and the heating continue.

Protostars with masses less than roughly 0.08 M⊙ (1.6-1029 kg) never reach temperatures high enough for nuclear fusion of hydrogen to begin. These are known as brown dwarfs.

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protostar Stage in star formation when the interior of a collapsing cloud of gas is sufficiently hot and dense that it becomes opaque to its own radiation, but not hot enough for the onset of nuclear reactions. [More Info: Field Guide] ...


A collection of interstellar gas and dust whose gravitational pull is causing it to collapse on itself and form a star.
Pulsar ...

Protostars often exhibit strong winds. Radio and infrared observations of hydrogen and carbon monoxide molecules, again in the Orion cloud, have revealed gas expanding outward at velocities approaching 100 km/s.

: A forming star, prior to settling down to the main sequence and burning hydrogen in its core.

A protostar will reach a temperature of 2000 to 3000 K, hot enough to glow a dull red with most of its energy in the infrared. The cocoon of gas and dust surrounding them blocks the visible light.

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The initial collapse occurs quickly, over a period of a few years. As the star heats up, pressure builds up following the Perfect Gas Law:
PV = NRT ...

The protostar, embedded within a cloud of gas and dust known as RCM 120, is destined to evolve into one of the biggest and brightest stars in our Galaxy within the next few hundred thousand years.

The , located in the Perseus Spiral Arm of the Milky Way Galaxy, is 300 times the size of the solar system.
NGC 188 (Caldwell 1) ...

The protostar "bits" are all destined to become individual stars of assorted mass. Less massive lumps become low mass stars while massive lumps become high mass stars. As a general rule there are lots of low mass stars for every high mass star.

Many contractions have been observed in isolated gas clouds; that is, where one cloud contracted to form one star.

Each protostar collapses very quickly; its gas falls inward in free fall. A protostar can collapse from a size equal to the outer diameter of the solar system to about 30 times the Sun's size (the size of Mercury's orbit) in about six months.

In some s, contraction remains the only source of energy; these are brown dwarfs, and they die away slowly, over hundreds of billions of years.

This is known as a protostar. At this stage the temperature is still too low for nuclear fusion to happen. If the mass is too low, the failed star ends up as a brown dwarf. Some astronomers consider Jupiter to be a failed star.

The light from a is absorbed by the dust surrounding it, causing the dust to warm up and radiate in the infrared.

T TAURI STAR - Protostar in the late stages of formation, often exhibiting both periodic and random fluctuations in brightness.

See also: See also: Star, Astro, Planet, Solar, Sun

Astronomy  Protoplanet  Protostellar disk

 
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