What is a star?

Question

Hi, I thought a star was simply a sun like ours that has orbiting planets and moons but I'm now not sure, am i right?
Thanks

Answer 1

star (stär) KEY

NOUN:


A self-luminous celestial body consisting of a mass of gas held together by its own gravity in which the energy generated by nuclear reactions in the interior is balanced by the outflow of energy to the surface, and the inward-directed gravitational forces are balanced by the outward-directed gas and radiation pressures.
Any of the celestial bodies visible at night from Earth as relatively stationary, usually twinkling points of light.
Something regarded as resembling such a celestial body.
A graphic design having five or more radiating points, often used as a symbol of rank or merit.

An artistic performer or athlete whose leading role or superior performance is acknowledged.
One who is highly celebrated in a field or profession.

An asterisk (*).
The star key on a telephone: For customer service, press star.
A white spot on the forehead of a horse.
A planet or constellation of the zodiac believed in astrology to influence personal destiny.
stars The future; destiny. Often used with the.
ADJECTIVE:

Outstanding or famous, especially in performing something: a star researcher; a star figure skater.
Of or relating to a star or stars.
VERB:
starred , star·ring , stars
VERB:
tr.

Answer 2

A star is a massive, luminous ball of plasma. Stars group together to form galaxies, and they dominate the visible universe. The nearest star is the Sun, which is the source of most of the energy on Earth, including daylight. Other stars are visible in the night sky, when they are not outshone by the Sun. A star shines because nuclear fusion in its core releases energy which traverses the star's interior and then radiates into outer space. Without stars, life on Earth and most atomic elements would not exist.

Astronomers can determine the mass, age, chemical composition and many other properties of a star by observing its spectrum, luminosity and motion through space. The total mass of a star is the principal determinant in its evolution and eventual fate. Other characteristics of a star that are determined by its evolutionary history include the diameter, rotation, movement and temperature. A plot of the temperature of many stars against their luminosities, known as a Hertzsprung-Russell diagram (H-R diagram), allows the current age and evolutionary state of a particular star to be determined.

A star begins as a collapsing cloud of material that is composed primarily of hydrogen along with some helium and heavier trace elements. Once the stellar core is sufficiently dense, some of the hydrogen is steadily converted into helium through the process of nuclear fusion. The remainder of the star's interior carries energy away from the core through a combination of radiation and convective processes. These processes keep the star from collapsing upon itself and the energy generates a stellar wind at the surface and radiation into outer space.

Once the hydrogen fuel at the core is exhausted, a star of at least 0.4 times the mass of the Sun expands to become a red giant, fusing heavier elements at the core, or in shells around the core. It then evolves into a degenerate form, recycling a portion of the matter into the interstellar environment where it will form a new generation of stars with a higher proportion of heavy elements.

Binary and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution.

Answer 3

The sun is a star. Not all (or many) stars are like the sun. Some are bigger. Some are smaller. Some are hotter. Some are cooler. Some are less dense. Some are more dense.

I don't know what the astronomical definition is, but I would say that a star is a chunk of matter that is emitting, did emit, or is capable of emitting energy as a result of nuclear fusion.

Answer 4

A star is a massive, luminous ball of plasma. Stars group together to form galaxies, and they dominate the visible universe. The nearest star is the Sun, which is the source of most of the energy on Earth, including daylight. Other stars are visible in the night sky, when they are not outshone by the Sun. A star shines because nuclear fusion in its core releases energy which traverses the star's interior and then radiates into outer space. Without stars, life on Earth and most atomic elements would not exist.

Astronomers can determine the mass, age, chemical composition and many other properties of a star by observing its spectrum, luminosity and motion through space. The total mass of a star is the principal determinant in its evolution and eventual fate. Other characteristics of a star that are determined by its evolutionary history include the diameter, rotation, movement and temperature. A plot of the temperature of many stars against their luminosities, known as a Hertzsprung-Russell diagram (H-R diagram), allows the current age and evolutionary state of a particular star to be determined.

A star begins as a collapsing cloud of material that is composed primarily of hydrogen along with some helium and heavier trace elements. Once the stellar core is sufficiently dense, some of the hydrogen is steadily converted into helium through the process of nuclear fusion. The remainder of the star's interior carries energy away from the core through a combination of radiation and convective processes. These processes keep the star from collapsing upon itself and the energy generates a stellar wind at the surface and radiation into outer space.[1]

Once the hydrogen fuel at the core is exhausted, a star of at least 0.4 times the mass of the Sun[2] expands to become a red giant, fusing heavier elements at the core, or in shells around the core. It then evolves into a degenerate form, recycling a portion of the matter into the interstellar environment where it will form a new generation of stars with a higher proportion of heavy elements.[3]

Binary and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution.

You could get more information from the link below...

Answer 5

A star is a massive, luminous ball of plasma. Stars group together to form galaxies, and they dominate the visible universe. The nearest star is the Sun, which is the source of most of the energy on Earth, including daylight. Other stars are visible in the night sky, when they are not outshone by the Sun. A star shines because nuclear fusion in its core releases energy which traverses the star's interior and then radiates into outer space. Without stars, life on Earth and most atomic elements would not exist.

Answer 6

a star, in it's literal sense, is a sun. but the stars we see in the sky at night are a number of things. from planets, to asteroids, to other galaxies entirely. there are also things like novas, super novas, quazars, nebulas, just to name a few things that are seen as "stars" with the naked eye.

Answer 7

Yes you are right but the guy above me is wrong in saying that they are sun's I think thats the name we give to our star not all stars

when i said guy above me I mean the first answer

Answer 8

It is a sun. It may not be exactly like ours, and may not have planets orbiting, but yes, it is a sun.

Answer 9

Star
A self-luminous body that during its life generates (or will generate) energy and support by thermonuclear fusion.

Answer 10

Everything you could possibly want to know about stars; from definition, to formation, to death...

http://en.wikipedia.org/wiki/Star