What does the spectral lines tell us about stars?
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.
Do stars have emission lines?
These peaks are called “emission lines,” because the cloud emits light. Emission lines also depend on the temperature of a star; they only appear if a star is at the right temperature.
What type of spectra do stars produce?
Stars have absorption line spectra. We can think of stars as a hot continuum source with a “cool” atmosphere of absorbing gas. The wavelengths that get absorbed depend on the chemical make up of the gas in the stellar atmosphere.
What are hydrogen lines in stars?
Hydrogen Lines: The Balmer Thermometer One of the best examples of this temperature sensitivity comes by comparing the Balmer lines, which are emission lines produced by neutral hydrogen atoms. The strength of these lines in the spectrum of a star is an excellent indication of the temperature of that star.
Do stars have atmospheres?
The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone.
Which type of stars have molecular lines?
A dominant characteristic of spectral class A stars is the presence of strong hydrogen lines, but ionized helium lines are only present in the class O stars….
| Spectral Classification Sequence | K |
|---|---|
| Neutral metals, molecular bands begin to appear | |
| 3500 – 5000 | |
| Aldebaran, Arcturus |
Why are spectral lines useful in classifying stars?
Classification of Stellar Spectra. Astronomers use the patterns of lines observed in stellar spectra to sort stars into a spectral class. Because a star’s temperature determines which absorption lines are present in its spectrum, these spectral classes are a measure of its surface temperature.
What produces 21cm emission lines?
The hydrogen line, 21-centimeter line, or H I line is the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. This electromagnetic radiation has a precise frequency of 1420405751.
What causes 21cm emission?
21-centimetre radiation, electromagnetic radiation of radio wavelength emitted by cold, neutral, interstellar hydrogen atoms. The hydrogen atom is composed of a positively charged particle, the proton, and a negatively charged particle, the electron. These particles have some intrinsic angular momentum called spin.