Search results
Results from the WOW.Com Content Network
The effective temperature of the Sun (5778 kelvins) is the temperature a black body of the same size must have to yield the same total emissive power.. The effective temperature of a star is the temperature of a black body with the same luminosity per surface area (F Bol) as the star and is defined according to the Stefan–Boltzmann law F Bol = σT eff 4.
1 Calculation of equilibrium temperature. ... temperature is a theoretical temperature that ... written in terms of the temperature and radius of the star:
The temperature of stars other than the Sun can be approximated using a similar means by treating the emitted energy as a black body radiation. [28] So: L = 4 π R 2 σ T 4 {\displaystyle L=4\pi R^{2}\sigma T^{4}} where L is the luminosity , σ is the Stefan–Boltzmann constant, R is the stellar radius and T is the effective temperature .
In principle, the temperature of a star can be calculated directly from the B−V index, and there are several formulae to make this connection. [6] A good approximation can be obtained by considering stars as black bodies, using Ballesteros' formula [7] (also implemented in the PyAstronomy package for Python): [8]
From this measurement and the apparent magnitudes of both stars, the luminosities can be found, and by using the mass–luminosity relationship, the masses of each star. These masses are used to re-calculate the separation distance, and the process is repeated. The process is iterated many times, and accuracies as high as 5% can be achieved. [8]
Blacksmiths work iron when it is hot enough to emit plainly visible thermal radiation. The color of a star is determined by its temperature, according to Wien's law. In the constellation of Orion, one can compare Betelgeuse (T ≈ 3800 K, upper left), Rigel (T = 12100 K, bottom right), Bellatrix (T = 22000 K, upper right), and Mintaka (T = 31800 K, rightmost of the 3 "belt stars" in the middle).
Evolution of the solar luminosity, radius and effective temperature compared to the present-day Sun. After Ribas (2010) [1] The solar luminosity (L ☉) is a unit of radiant flux (power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun.
where G is the gravitational constant, M is the mass of the star, R is the radius of the star, and L is the star's luminosity. As an example, the Sun 's thermal time scale is approximately 15.7 million years.