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Which star has a radius of 10 km?
That's the approximate radius of a neutron star, a.k.a. a pulsar.
What is the surface area of a star?
Roughly 12.57 times the square of its radius.
What is a hypergiant's radius?
A red hypergiant star could have a radius of up to 2000 solar radii or more, where one solar radius is the radius of our sun. If at the centre of our solarsystem, a hypergiant could extend out as far as Jupiter or more.
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!
What are the angles of a regular 4 pointed star?
As far as I know, there is no "regular" 4 pointed star. However, if you have a 4 pointed star, you can draw a circle through it's inner points and a second circle around its outer points. If we say that the inner circle has radius "r" and the outer circle has radius "R", that the angle, "a", of the star's points are: a = atan(2r / (R√2 - r) If the outer circle is twice as big as the inner circle, this becomes: a = atan(2r / (2r√2 - r) = atan(2 / (2√2-1) = 47.5°
In what unit do I measure the radius of a star?
You can use kilometers. Or you can compare it to the radius of our Sun, and say, for example, "This star has 600 times the diameter [or radius] of our Sun."
Which star has a radius of 10 km?
That's the approximate radius of a neutron star, a.k.a. a pulsar.
Temperature and radius of merak star?
the distances of the merak star
What kind of star is hot and has a very small radius?
north star
What is the radius of the star Rigel?
Rigel has a radius of about 78 solar radii or 0.363 AU.
Why does the luminosity of the star depend on both its radius and its temperature?
The bigger the star's radius, the greater its surface area which emits the light. The bigger the temperature, the more luminous is the light the star is emitting.
What is the area of a star?
It's (4 pi) times (the star's radius)2.
How big is barnards star?
It has a radius of between 0.15 and 0.20 that of our Sun. The Sun has a radius of about 696,000 km, so Barnard's Star has a radius of between 104,400 km and 139,200. Average about 121,800 km
How wide is alnitak?
Alnitak is a multiple star: Alnitak Aa has a radius which is 20 time the sun's radius.
How much bigger is Pistol Star than the Sun?
Its radius is estimated to be about 300 times the radius of the Sun.
What is the radius of a red giant star?
A red giant can have a radius of 50 million to 500 million kilometres.
How can solar radii be used to describe the sizes of star including the subgroups of white dwarf giants and supergiants?
A star's radius is the distance from it centre to its visible surface. The bigger the star, the larger the radius. The radius is not the best means of comparing stars, it is perhaps better to compare stars by their mass.
