White Dwarfs and Giants
It's the main sequence because on the H-R diagram most of the stars fall on or near this line.
Most of the stars in the universe are found on the main sequence. Stars fall off the main sequence when they begin to die.
Some examples of star types that are not part of the Main Sequence are:Red Giants, Blue Giants, Brown Dwarfs, and White Dwarfs.When stars are plotted on a chart that compares their Temperature (color) to their Brightness (Luminosity), most of them fall into a diagonal line across the chart.That chart is known as a Hertzsprung-Russell diagram and the diagonal line on it is called the Main Sequence of stars.Stars on the Main Sequence fit this pattern because they are in balance between collapse and expansion. Their gravity that is trying to collapse them is in balance with their nuclear fusion that is trying to expand them.A difference to notice between Main Sequence stars and other stars is:Main Sequence stars are dimmer if they are cooler and brighter if they are hotter.Giant stars are brighter whether they are hot or cool.Dwarf stars are dimmer whether they are hot or cool.
That they all fall on the main sequence.
In the early 20th century, Danish astrophysicist Ejnar Hertzsprung and American astrophysicist Henry Norris Russell independently developed a graph now known as the Hertzsprung-Russell (H-R) diagram, which plots absolute brightness against spectral type. In this diagram, the brightest stars lie near the top of the diagram and the hottest stars lie to the left. On the H-R diagram, most of the stars, including the Sun, fall along a diagonal line that goes from the upper left to the lower right of the diagram. This line called the main sequence.The great majority of stars neighboring the Sun fall on the lower part of the H-R diagram's main sequence, and relatively few lie on the portion of the main sequence above the Sun. This means that most of the Sun's neighboring stars are both cooler and fainter (in absolute magnitude) than the Sun. A smaller population of brighter but cooler stars known as supergiants occupies the uppermost region of the diagram. Some stars, which are difficult to discover because they are so intrinsically faint, lie near the bottom of the H-R diagram. These faint stars are called white dwarfs.
It's the main sequence because on the H-R diagram most of the stars fall on or near this line.
The main sequence is a line on a Hertzsprung-Russell diagram, on which every star is placed on a graph of absolute magnitude against surface temperature. Each star produces a dot on the diagram, and all the main sequence stars fall roughly on a straight line. On the main sequence the hot bright stars are on the top left and the cooler dimmer red stars are on the lower right. The Sun is just above halfway up.
Most of the stars in the universe are found on the main sequence. Stars fall off the main sequence when they begin to die.
Some examples of star types that are not part of the Main Sequence are:Red Giants, Blue Giants, Brown Dwarfs, and White Dwarfs.When stars are plotted on a chart that compares their Temperature (color) to their Brightness (Luminosity), most of them fall into a diagonal line across the chart.That chart is known as a Hertzsprung-Russell diagram and the diagonal line on it is called the Main Sequence of stars.Stars on the Main Sequence fit this pattern because they are in balance between collapse and expansion. Their gravity that is trying to collapse them is in balance with their nuclear fusion that is trying to expand them.A difference to notice between Main Sequence stars and other stars is:Main Sequence stars are dimmer if they are cooler and brighter if they are hotter.Giant stars are brighter whether they are hot or cool.Dwarf stars are dimmer whether they are hot or cool.
That they all fall on the main sequence.
In the early 20th century, Danish astrophysicist Ejnar Hertzsprung and American astrophysicist Henry Norris Russell independently developed a graph now known as the Hertzsprung-Russell (H-R) diagram, which plots absolute brightness against spectral type. In this diagram, the brightest stars lie near the top of the diagram and the hottest stars lie to the left. On the H-R diagram, most of the stars, including the Sun, fall along a diagonal line that goes from the upper left to the lower right of the diagram. This line called the main sequence.The great majority of stars neighboring the Sun fall on the lower part of the H-R diagram's main sequence, and relatively few lie on the portion of the main sequence above the Sun. This means that most of the Sun's neighboring stars are both cooler and fainter (in absolute magnitude) than the Sun. A smaller population of brighter but cooler stars known as supergiants occupies the uppermost region of the diagram. Some stars, which are difficult to discover because they are so intrinsically faint, lie near the bottom of the H-R diagram. These faint stars are called white dwarfs.
T Tauri stars are pre-Main Sequence stars which are large but not as hot as O and B Main Sequence stars. They mainly fall in the categories of F, G, K or M, and they are not yet on the Main Sequence because they are still accreting mass and are still very young and unstable.
The five primary types of stars are the red dwarf star, yellow star, blue giant star, giant star, and super giant star. The billions of stars in the universe fall under one of these classifications.
In astronomy the term main sequence is understood to apply to stellar evolution; since black holes are not themselves considered stars so much as "stellar remnants" they would not fall on this sequence. It would be appropriate to say they are most commonly created at the end of life (once the fuel is exhausted) of a larger star and thus would be more likely to pertain to the most massive stars of the upper main sequence.
The Hertzsprung-Russell diagram is a scatter graph of known stars. It shows the absolute magnitudes (actual brightness at a set distance) versus the spectral type or classification (which is effectively what their temperature is). Stars, when plotted onto this graph, tend to fall into set patterns. The position of a star within a pattern (or sequence) can give further information, such as how old the star is.
Stars Don't Fall was created in 2005.
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