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After stellar ignition, the star becomes relatively stable. All the energy in a star is made in its centre (its core), by a process called nuclear fusion. The star releases the energy as heat and light. This is what makes a star shine. The outward force generated by the fusion process is balanced by the inward pull of the star's gravity. It is ...
- What Is A Stellar Spectrum?
- Surface Temperature
- Chemical Composition
- Motion of The Star
- Density
Stars emit radiation which includes visible light (400-700 nm). For example, the Sun emits white light that can be captured and observed on a spectrometer. Instead of seeing a continuous spectrum, the stellar spectra of the Sun contain absent wavelengths (absorption lines) within the spectrum. This is referred to as the absorption spectrumor stella...
The spectra of stars consist of a wide range of wavelengths. Each wavelength of radiation has a different intensity. The peak wavelengthrefers to the wavelength with the highest intensity. We can use this information to compare the relative surface temperature between stars. Wien’s displacement lawquantitatively describes this relationship: Stars w...
When light is emitted by the star, some of its energy absorbed by atoms in the outer layers of its atmosphere. This occurs when the energy matches exactly the excitation energy of electrons in the ground state of these elements. The absorption spectral lines represent the energy that has been absorbed by these electrons. Stars are composed of diffe...
Doppler’s Effect
1. The wavelength or frequency of a wave is influenced by the wave’s relatively velocity to the observer. 2. If the emitter or source of wave is moving towards the observer, the resultant wave has shorter wavelength and greater frequency. 3. If the emitter or source of wave is moving away from the observe, the resultant wave has longer wavelength and lower frequency. Review Doppler's Effect here Translational Velocity The following three spectra are for a hydrogen atom. The movement of stars,...
Width of absorption spectral lines also reveal information about the density of stars. Density and pressure, at the surface of a star can also broaden spectral lines, but the intensity varies across the line in different way from the effect of rotation. In higher density stars, the increased gas pressure produces more rapid collision between atoms....
Stars form in large clouds of gas and dust called molecular clouds. Molecular clouds range from 1,000 to 10 million times the mass of the Sun and can span as much as hundreds of light-years. Molecular clouds are cold which causes gas to clump, creating high-density pockets. Some of these clumps can collide with each other or collect more matter ...
The Milky Way galaxy is about 100,000 light years across, and we are seeing the closest stars: most visible to the naked-eye stars are within 4,000 light years. The average lifetime of a star depends on how big it is: the brightest, most massive stars last for about 10 million years; stars like our sun can burn for about 10 billion years, and the dimmest, reddest stars can shine for about 100 ...
Jul 31, 2020 · Earth is fortunate to be orbiting a star that is fairly constant in its light production. The amount of light energy reaching Earth from the Sun has varied by much less than 1 percent over the ...
Variable Stars. The breakthrough in measuring distances to remote parts of our Galaxy, and to other galaxies as well, came from the study of variable star s. Most stars are constant in their luminosity, at least to within a percent or two. Like the Sun, they generate a steady flow of energy from their interiors.
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Sep 23, 2021 · Stars. A star is a sphere of gas held together by its own gravity. The closest star to Earth is our very own Sun, so we have an example nearby that astronomers can study in detail. The lessons we learn about the Sun can be applied to other stars. Tell me more about the Sun; A star's life is a constant struggle against the force of gravity.
