Table of Contents
- 1 What determines spectral lines are present?
- 2 What determines the spectra of a star?
- 3 What are the factors that affect the width of a spectral line?
- 4 How are spectral lines formed?
- 5 Does luminosity determine the classification of stars?
- 6 Do stars emit a continuous spectrum?
- 7 How many spectral lines are there?
- 8 What causes the broadening of spectral lines?
- 9 What can spectroscopy tell us about a star?
- 10 What is the significance of a spectral line?
- 11 How do astronomers determine what kind of stuff is in stars?
What determines spectral lines are present?
The presence of spectral lines is explained by quantum mechanics in terms of the energy levels of atoms, ions and molecules. Emission lines occur when the electrons of an excited atom, element or molecule move between energy levels, returning towards the ground state.
What determines the spectra of a star?
The spectrum of a star is composed mainly of thermal radiation that produces a continuous spectrum. The peak emission of their thermal radiation (the continuum peak in the spectrum above) comes at a wavelength determined by the star’s surface temperature — the hotter the star, the bluer the continuum peak.
How do you determine the number of spectral lines emitted?
Therefore, the total no. of spectral lines= 6(6–1)/2 = 15. Therefore, there are 15 spectral lines obtained on spectrograph when an electron jumps from 6th orbit to 1st orbit of hydrogen atom.
What are the factors that affect the width of a spectral line?
Widths of Spectral Lines (continued)
How are spectral lines formed?
Spectral lines are produced by transitions of electrons within atoms or ions. As the electrons move closer to or farther from the nucleus of an atom (or of an ion), energy in the form of light (or other radiation) is emitted or absorbed.…
Why elements produce different numbers of spectral lines?
Each element has its own unique line spectrum and is thus referred to as the “fingerprint” for a particular element. The spectra for each element are unique because each element contains differing numbers of electrons and thus different energy levels.
Does luminosity determine the classification of stars?
The most widely used system of star classification divides stars of a given spectral class into six categories called luminosity classes. These luminosity classes are denoted by Roman numbers as follows: Ia: Brightest supergiants. IV: Subgiants (intermediate between giants and main-sequence stars)
Do stars emit a continuous spectrum?
Because radiation leaving the inner regions of a star forms a continuous spectrum. However different particles in the photosphere absorb particular wavelengths as the radiation passes through it. As a result there are gaps in the spectrum – spectral lines – and the results is an absorption spectrum.
What is the number of spectral lines produced when an electron?
The number of spectral lines that are possible when electrons in the 7th shell in different hydrogen atoms return to the second shell is 15.
How many spectral lines are there?
He found that the four visible spectral lines corresponded to transitions from higher energy levels down to the second energy level (n = 2). This is called the Balmer series.
What causes the broadening of spectral lines?
In atomic physics, Doppler broadening is the broadening of spectral lines due to the Doppler effect caused by a distribution of velocities of atoms or molecules. Different velocities of the emitting particles result in different Doppler shifts, the cumulative effect of which is the line broadening.
Why are some spectral lines thicker?
The higher the temperature of the gas, the wider the distribution of velocities in the gas. Since the spectral line is a combination of all of the emitted radiation, the higher the temperature of the gas, the broader the spectral line emitted from that gas.
What can spectroscopy tell us about a star?
The science of spectroscopy is quite sophisticated. From spectral lines astronomers can determine not only the element, but the temperature and density of that element in the star. The spectral line also can tell us about any magnetic field of the star. The width of the line can tell us how fast the material is moving.
What is the significance of a spectral line?
A spectral line is like a fingerprint that can be used to identify the atoms, elements or molecules present in a star, galaxy or cloud of interstellar gas. If we separate the incoming light from a celestial source using a prism, we will often see a spectrum of colours crossed with discrete lines. Note that spectral lines can also occur in other
What are spectral characteristics of stars?
Spectral characteristics offer a way to classify stars which gives information about temperature in a different way – particular absorption lines can be observed only for a certain range of temperatures because only in that range are the involved atomic energy levels populated. The standard classes are: Temperature O 30,000 – 60,000 K
How do astronomers determine what kind of stuff is in stars?
Thus, astronomers can identify what kinds of stuff are in stars from the lines they find in the star’s spectrum. This type of study is called spectroscopy . The science of spectroscopy is quite sophisticated. From spectral lines astronomers can determine not only the element, but the temperature and density of that element in the star.