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Why would two stars have different sizes and tempertes but same luminosity?
Wiki User
∙ 13y ago
The luminosity depends on what stage of its life cycle the star is in. Also, the apparent luminosity depends on the distance from earth.
Wiki User
∙ 13y ago
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What is anH-R diagram?
That's short for Hertzsprung-Russel diagram. It is a diagram in which the total luminosity versus color (and therefore temperature) of many stars is plotted.
When and why is scientific notation used?
Scientific notation is used in numbers that are very large, or small- also if they include many zeroes. For example, they are used to show atomic values of distances/sizes of celestial beings. (the sun, stars, etc) Or, an electron's weight.
How do you measure a stars radius?
Calculating a star's radius is a somewhat lengthy process. You have to put together many tools that you have developed in various SkyServer projects. Even the largest star is so far away that it appears as a single point from the surface of the Earth - its radius cannot be measured directly. Fortunately, understanding a star's luminosity provides you with the tools necessary to calculate its radius from easily measured quantities. A star's luminosity, or total power given off, is related to two of its properties: its temperature and surface area. If two stars have the same surface area, the hotter one will give off more radiation. If two stars have the same temperature, the one with more surface area will give off more radiation. The surface area of a star is directly related to the square of its radius (assuming a spherical star). The luminosity of a star is given by the equation L = 4pR2s T4, Where L is the luminosity in Watts, R is the radius in meters, s is the Stefan-Boltzmann constant (5.67 x 10-8 Wm-2K-4), and T is the star's surface temperature in Kelvin. The temperature of a star is related to its b-v magnitude. for b-v value go to link The calculation is actually somewhat easier if we try to find the ratio of another star's radius to that of our Sun. Let Ls be the luminosity of the Sun, L be the luminosity of another star, Ts be the temperature of the Sun, T be the temperature of the other star, Rs be the radius of the Sun, and R be the radius of the other star. We can then write the ratio of their luminosities as L/Ls = (4pR2sT4)/(4pRs2sTs4) = (R/Rs)2(T/Ts)4 Solving for the ratio R/Rs yields R/Rs = (Ts/T)2(L/Ls)1/2 The temperatures can be found approximately from the table above by looking at the B-V values. To find the ratio L/Ls, we can use the absolute magnitudes of the stars. The magnitude scale is a logarithmic scale. For every decrease in brightness of 1 magnitude, the star is 2.51 times as bright. Therefore, L/Ls can be found from the equation L/Ls = 2.51Dm, where Dm = ms - m Let's look at the star Sirius. It has visual magnitude of -1.44, B-V of .009, and a parallax of 379.21 milli arc seconds. Finding its distance from its parallax yields d = 1/p = 1/.37921 = 2.63 parsecs. Its absolute magnitude is M = m - 5 log d + 5 = -1.44 - 5 log (2.63) + 5 = 1.46 We know the temperature of the Sun is 5800K. From the chart, the temperature of Sirius is about 9500K. Our Sun has an absolute magnitude of 4.83. The difference in magnitude is 3.37. Putting everything together yields R/Rs = (5800/9500)2(2.5123.37)1/2 = 1.76 Sirius has a radius approximately 1.76 times that of our Sun!
Is the number of stars finite or infinite?
The number of stars is finite.
What did the Sumerians use to develop their calendar?
the shape of the stars the shape of the stars
How are stars classifieds?
Stars are classified by their color, temperatures, sizes, and brightness, it could also be by composition and radiation.Scientists classify stars by color, luminosity, and temperature.
Are The most common type of stars are low luminosity stars?
Yes. Around 76% of the stars are low luminosity stars.
What is a sentence with luminosity?
The stars in the night sky shine with a remarkable luminosity.
Do all star have the same light? why or why not?
No. Stars of different sizes and composition have different luminosity (light) levels. A very big star will most likely be blue and shines very brightly, while small stars like white dwarf stars emit very white light, but are mostly very dim.
How do you determine a stars luminosity?
To determine a star's luminosity is from size and temperature.
What are the kind of stars according to their size?
Stars come in different shapes, sizes, colors. This is due to the amount of spectra and temperature in each for classifying stars.Astronomers often use the Hertzsprung-Russell (H-R) Diagram plots stars color, temperature, luminosity, spectral type, and even evolutionary type.
What are different sizes or stars?
dwarf stars,giant stars,main sequence stars
If a star is blue is its luminosity high or low?
Blue stars are very hot stars and so usually have high luminosity.
Why are most visual binary stars of low luminosity?
If the binary stars were of too high luminosity it would be impossible to distinguish the two through vision alone. Therefore most visual binary stars are of low luminosity.
What process of losing their outer layer causes stars to lose?
luminosity or brightness
What does a stars luminosity measure?
Luminosity is the total amount of energy emitted by a star per second.
What is the stars intrinsic brightness called?
Luminosity.
