stellar diameter
Quick Summary
Stellar diameter, or radius, refers to the physical size of a star. This can be measured directly for bright, large stars using techniques like interference of light or speckle interferometry. For stars in binary systems, analyzing light curves during eclipses can reveal their dimensions.1
The Sun serves as a benchmark, with a radius of approximately 700,000 km. Stars vary greatly in size:2
* Dwarf stars are comparable to the Sun.2
* Giant stars are much larger, with radii tens of times that of the Sun.23
* Supergiant stars can have radii hundreds of times larger than the Sun.23
* White dwarf stars are exceptionally small, with radii comparable to Earth.23
A star's radius can also be calculated if its absolute magnitude and temperature are known, as temperature indicates energy emission per unit area, and luminosity provides total power output.1
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astronomyMeasuring observable stellar properties…several methods for measuring a star’s diameter. From the brightness and distance, the luminosity (L) can be calculated, and, from observations of the brightness at different wavelengths, the temperature (T) can be calculated. Because the radiation from many stars can be well approximated by a Planck blackbody spectrum (see Planck’s…
Read More…several methods for measuring a star’s diameter. From the brightness and distance, the luminosity (L) can be calculated, and, from observations of the brightness at different wavelengths, the temperature (T) can be calculated. Because the radiation from many stars can be well approximated by a Planck blackbody spectrum (see Planck’s…
Read More
starStellar radiiAngular sizes of bright red giant and supergiant stars were first measured directly during the 1920s, using the principle of interference of light. Only bright stars with large angular size can be measured by this method. Provided the distance to the star is…
Read MoreAngular sizes of bright red giant and supergiant stars were first measured directly during the 1920s, using the principle of interference of light. Only bright stars with large angular size can be measured by this method. Provided the distance to the star is…
Read More