The radius of a star that has a surface temperature of 28,575 K and is 10000 times brighter than the sun is ____ Rsun.
Answers
Answer:
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. The table below can help you find the temperature of the star based on its b-v magnitude.