The amount of time a star spends in its main sequence is determined mainly by its mass. A more massive star uses up its fuel faster, so it has a shorter life (and passes less time on the main sequence).
There are quite a few factors that affect the spectrum of a star. The two primary factors, however, are the temperature of the star, and the composition of the star.
A star made up of different amounts of various elements will show a different spectrum.
A star with a different temperature dictates how those elements will be shown in the spectra. This is very important, as stars at certain temperatures can actually "hide" some elements entirely.
Take hydrogen for example. If a star is to cold, the hydrogen atoms don't interact with the light much, and produce a weak spectrum. To hot, and the atoms are ionized (the electrons stripped from the nucleus) and are completely unable to absorb or emit light. Thus they do not contribute the spectrum at all. The are there, but "hidden".
From the spectrum you can also determine many other traits about the star. You can determine pressure, rotation, and radial motion and a few other traits as well.
The color of a star depends on the heat being released.
Red is cold if by cold you mean~5,400-6,300 degrees Fahrenheit but still, cold for a star.
Next is orange, 6300-9000 degrees Fahrenheit.
Next is yellow 9000-10800 degrees Fahrenheit.
Next is white 10800-13500 degrees Fahrenheit.
Next is blue-white 13500-20000 degrees Fahrenheit.
Next is blue (type b) 20800-45000 degrees Fahrenheit.
Next blue (type o) 45000-75000 degrees Fahrenheit.
A star's color is based on its temperature. Temperature is based on density and how much fuel is left in the star. This is determined by how old the star is and how large it is, but all of this just changes the temperature. So, a star's color is based on temperature.
There are several factors, including where the stalker sets them on fire, amount of beauty products the star is wearing, and how much of the star's body is silicone, but the main factor is how long the paparazzi snap photos before they decide to put the star out.
If a star is known to lie on the main sequence, measurement of its spectral type allows its luminosity to be estimated and its distance to be measured. This method of distance determination, which is valid for stars up to several thousand parsecs from Earth, is called spectroscopic parallax. A star's luminosity class allows astronomers to distinguish main-sequence stars from giants and supergiants of the same spectral type.
Yes, there is a way to determine its structure just by observing the light emitted from it. Not only this but they can even determine if it is moving towards us or moving away. This is called the 'Doppler effect'. Back to the structure, when you observe the star there are little 'holes' in the spectrum of the light emitted. Each chemical element 'consumes' a part from the hole light-spectrum. What is left is a black hole(not to be confused with the the term 'Black Hole') in the spectra and it means that certain element is present in the structure of the star.
Basically, the mass. The more massive the star, the shorter its lifetime.
A stars color reveals its surface temperature. x
The lifetime of a star depends, to a great extent, on its mass. More massive stars use up their fuel, and then die, much more quickly than smaller (less massive) stars.
main sequence
Barnard's star is a red dwarf, M-type main sequence star.
The Sun is a yellow main sequence star of type G2 V.
Main sequence stars
Earth's star is what we call the Sun, and it is a main-sequence star with a G2 spectrum and an absolute magnitude of +4.7.
main sequence star
a main sequence star
it is a main sequence star
it is a white main sequence star
it is a white main sequence star
A Main Sequence star.
A Main Sequence star.
main sequence
Barnard's star is a red dwarf, M-type main sequence star.
The largest main sequence stars are blue.
Menkalinan is a white main-sequence star in the shoulder of Auriga.
The sun is a G-type main sequence star.