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The relationship is represented by the equation: = where L ⊙ and M ⊙ are the luminosity and mass of the Sun and 1 < a < 6. [2] The value a = 3.5 is commonly used for main-sequence stars. [ 3 ] This equation and the usual value of a = 3.5 only applies to main-sequence stars with masses 2 M ⊙ < M < 55 M ⊙ and does not apply to red giants ...
Mass-to-light ratios in application can be used to gain insight into the dark matter content and dust extinction in a galaxy. [4] Historically, rotation curves for spiral galaxies have been used to study galaxies, but mass-to-light ratios prove more accurate as a method of measuring mass. [5]
A preliminary description of the three areas of this diagram was made in 2003 by Eric F. Bell et al. from the COMBO-17 survey [1] that clarified the bimodal distribution of red and blue galaxies as seen in the analysis of Sloan Digital Sky Survey data [2] and even in de Vaucouleurs's 1961 analyses of galaxy morphology. [3]
Henrietta Swan Leavitt (/ ˈ l ɛ v ɪ t /; July 4, 1868 – December 12, 1921) was an American astronomer. [2] [1] [3] Her discovery of how to effectively measure vast distances to remote galaxies led to a shift in the scale and understanding of the scale and the nature of the universe. [4]
The Tully–Fisher relation for spiral and lenticular galaxies. In astronomy, the Tully–Fisher relation (TFR) is a widely verified empirical relationship between the mass or intrinsic luminosity of a spiral galaxy and its asymptotic rotation velocity or emission line width. Since the observed brightness of a galaxy is distance-dependent, the ...
For example, the initial mass of a star is the primary factor of determining its colour, luminosity, radius, radiation spectrum, and quantity of materials and energy it emitted into interstellar space during its lifetime. [1] At low masses, the IMF sets the Milky Way Galaxy mass budget and the
The Sun is found on the main sequence at luminosity 1 (absolute magnitude 4.8) and B−V color index 0.66 (temperature 5780 K, spectral type G2V). The Hertzsprung–Russell diagram (abbreviated as H–R diagram , HR diagram or HRD ) is a scatter plot of stars showing the relationship between the stars' absolute magnitudes or luminosities and ...
The best-fit value of n correlates with galaxy size and luminosity, such that bigger and brighter galaxies tend to be fit with larger n. [ 5 ] [ 6 ] Setting n = 4 gives the de Vaucouleurs profile : I ( R ) ∝ e − b R 1 / 4 {\displaystyle I(R)\propto e^{-bR^{1/4}}} which is a rough approximation of ordinary elliptical galaxies .