Spectral lines are
often used to identify atoms and molecules
. These “fingerprints” can be compared to the previously collected “fingerprints” of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible.
What do spectral lines tell us?
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. We can learn about winds in stars from this.
What are two important things that we can learn from spectral lines?
Two very important things we can learn from spectral lines is
the chemical composition of objects in space and their motions
.
Why are spectral lines produced?
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 are absorption lines useful?
Astronomers use this fingerprint (which spans the entire spectrum)
to determine the composition of distant stars
(which are essentially balls of burning gas) as well as the atmosphere of stars and planets (that absorb light passing through their atmospheres).
Which element has the most spectral lines?
Mercury
: the strongest line, at 546 nm, gives mercury a greenish color. Fig. 2. When heated in a electric discharge tube, each element produces a unique pattern of spectral `lines’.
What is the cause of 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.
What is spectral analysis used for?
Spectral analysis provides
a means of measuring the strength of periodic (sinusoidal) components of a signal at different frequencies
. The Fourier transform takes an input function in time or space and transforms it into a complex function in frequency that gives the amplitude and phase of the input function.
Why are spectral lines like fingerprints?
Enough electrons jumping between any two given energy levels of a given element will result in a spectral emission or absorption line at a characteristic wavelength. Spectral lines are
used to identify the element
and thus, it is called fingerprint of elements.
How do astronomers learn about stars?
Astronomers learn about stars primarily
by analyzing the light the stars emit
. … It separates light into different colors, or wave legnths. Light passing through a spectrograph turns the light into a spectrum.
How many spectral lines are there?
The electron energy level diagram for the hydrogen atom. 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.
Why are spectral lines not sharp?
Real spectral lines are broadened because: –
Energy levels are not infinitely sharp
. – Atoms are moving relative to observer. energy E of levels with finite lifetimes. Determines the natural width of a line (generally very small).
How many spectral lines are produced?
Hence the final answer is
three spectral lines
lie in the visible region for the hydrogen atom when electrons jump from n2=5 to n1=1 in the visible region.
What causes absorption lines?
Absorption lines occur when
an atom, element or molecule absorbs a photon with an energy equal to the difference between two energy levels
. This causes an electron to be promoted into a higher energy level, and the atom, element or molecule is said to be in an excited state.
What are the factors affecting intensity of spectral lines?
- Amount of sample. The intensity of lines on the spectrum will be affected by the amount of sample which light passes through. …
- Population of energy states. …
- Spectroscopic selection rules.
What can absorption lines tell us?
As photons fly through the outermost layers of the stellar atmosphere, however, they may be absorbed by atoms or ions in those outer layers. The absorption lines produced by these outermost layers of the star tell us a lot about
the chemical compositition, temperature, and other features of the star
.
