what is the general relationship between temperature and star brightness? | Yahoo Answers
Astronomers (professional or amateur) can measure a star's brightness (the This is the relationship between luminosity (L), radius(R) and temperature (T): L. The mass and luminosity of a star also relate to its color. More massive stars are hotter and bluer, while less massive stars are cooler and have. According to Hubble, the color of stars can tell us whether the stars are receding from us and the speed of their acceleration. Now I read an.
While the sun will spend about 10 billion years on the main sequence, a star 10 times as massive will stick around for only 20 million years. A red dwarfwhich is half as massive as the sun, can last 80 to billion years, which is far longer than the universe's age of This long lifetime is one reason red dwarfs are considered to be good sources for planets hosting lifebecause they are stable for such a long time.
Though they look serene and silent from our vantage on Earth, stars are actually roiling balls of violent plasma.Astronomy - Ch. 17: The Nature of Stars (17 of 37) Wien's Law, Star's Color and Temperature
Test your stellar smarts with this quiz. Test Your Stellar Smarts Though they look serene and silent from our vantage on Earth, stars are actually roiling balls of violent plasma. Modern instruments have improved measurements of brightness, making them more precise. In the early 20th century, astronomers realized that the mass of a star is related to its luminosityor how much light it produces. These are both related to the stellar temperature. Stars 10 times as massive as the sun shine more than a thousand times as much.
The mass and luminosity of a star also relate to its color. More massive stars are hotter and bluer, while less massive stars are cooler and have a reddish appearance. The sun falls in between the spectrum, given it a more yellowish appearance.
Most stars lie on a line known as the "main sequence," which runs from the top left where hot stars are brighter to the bottom right where cool stars tend to be dimmer.
Constructing the Hertzsprung-Russell Diagram Hubble site ] When the stars go out Eventually, a main sequence star burns through the hydrogen in its core, reaching the end of its life cycle.
At this point, it leaves the main sequence. In the late 19th century, Harvard astronomers developed a system to classify stars not according to color, but by the strength by which hydrogen gas absorbed light at particular wavelengths. The star classes were labeled A to N in order of decreasing hydrogen absorption strength. This is the Harvard spectral classification, which is still used today. So what does this have to do with star color?
New e-Book gives you the best articles from the first three years of One-Minute Astronomer.
Characteristics of a Star | Sciencing
Tips, tales, and tours of the solar system and deep sky. Ideal for experienced and armchair stargazers. Absolute magnitude is simply a measure of how bright a star would appear if 10 parsecs distant and thus allows stars to be simply compared.
Just to confuse things, the lower or more negative the magnitude, the brighter the star.
In main-sequence stars, what is is the relationship between brightness and temperature?
Note how the temperature scale is reversed on the horizontal axis. Also take care if using magnitude to work upwards to negative values. The effective temperature of a star is plotted on the horizontal axis of an H-R diagram. One quirk here is that the temperature is plotted in reverse order, with high temperature around 30, - 40, K on the left and the cooler temperature around 2, K on the right.
Classifying Stars - the Hertzsprung-Russell Diagram
In practice astronomers actually measure a quantity called colour index that is simply the difference in the magnitude of a star when measured through two different coloured filters. Stars with a negative colour index are bluish whilst cooler orange or red stars have a positive colour index. The third possible scale for the horizontal axis is a star's spectral class. By splitting the light from a star through a spectrograph its spectrum can be recorded and analysed. Stars of similar size, temperature, composition and other properties have similar spectra and are classified into the same spectral class.
Our Sun is a G-class star. By comparing the spectra of an unknown star with spectra of selected standard reference stars a wealth of information, including its colour or effective temperature can be determined. If we now plot a Hertzsprung-Russell diagram for a few thousand nearest or brightest stars we see the following: Each dot represents a star.