Dimension of stars

Measuring the dimension of stars is a difficult task. Just calculate the diameter of the sun is relatively simple, but all the other stars, even in large telescopes are visible as points.

Measuring the dimension of stars is a difficult task

Despite this, scientists have found a way to measure the dimension of stars. This can be done, for example, by measuring the time of passage of a dark companion in a darkened variable star in front of a bright component and knowing the orbital velocity of the satellite. Such a method allows to calculate the dimensions of the two components. However, the distance to the majority of stars in varying degrees of inaccurate, which affects the determination of their dimension. Some big stars have long atmosphere and opaque dust drives.

Dimensions of stars can be determined by the following methods: Observations moon star eclipses can determine the angular dimension, and knowing the distance to the star, it is possible to determine its true linear dimensions; dimensions can be measured directly on a special device - an optical interferometer; dimensions can be calculated theoretically on the basis of estimates of the total luminosity and star temperature.

Dimensions of stars in most cases concluded between the value of the Earth's diameter and the size of planetary orbits. In rare cases, these dimensions are more than 2000 times greater than the diameter of the sun. The current division of stars into classes, which are both so-called luminosity classes, distinguish:

  1. Supergiants
  2. Bright giants
  3. Giants
  4. Subgiants
  5. Dwarfs

To determine the mass of the stars is also not easy. Reliable results are obtained by using Kepler's third law, especially in the study of the orbits of binary stars. The differences of the masses is not as great as those found dimensions of stars; they lie in the range from 0,05 to 50 solar masses (of course, there may be more of a star with a smaller mass, yet to be discovered).