Late in the 19th century, Harvard astronomer Edward Pickering wanted to sort and catalog the thousands of star spectra that had been collected by the Harvard Observatory. He hired several women to do the work, paying them 25 cents a day. The most prominent of these women was Annie Jump Cannon, who devised a classification system still used today.
Watch the video to learn more about Jump Cannon's work and how star spectra is used to classify stars.
Question 2
2.
Question: How are stars classified?
Use the elements you determined in Star 1's spectrum to classify it.
Hint: Look at the color of the star in the gizmo to help narrow down the possibilities so you know which spectra to test. For example, if a star appears white, look for whether the spectral lines match Class A or Class F.
Color: __________
Surface temperature (K): __________
Class: __________
Question 3
3.
Question 4
4.
Use the elements you determined in Star 2's spectrum to classify it.
Color: __________
Surface temperature (K): __________
Class: __________
Question 5
5.
Question 6
6.
Use the elements you determined in Star 4's spectrum to classify it.
Color: __________
Surface temperature (K): __________
Class: __________
Question 7
7.
Question 8
8.
A star's color is determined by its __________
What color stars are the hottest? __________
What color stars are the coolest? __________
What color stars have a medium temperature? __________
When light goes through a prism, it separates into many colors. This band of colors is called a spectrum. A rainbow is an example of a spectrum: red, orange, yellow, green, blue, violet.
The interior of a star produces a continuous spectrum of light, like a rainbow. Cooler gases in the outer layers of the star absorb certain wavelengths of light, causing dark lines to appear in the spectrum.
The resulting absorption spectrum can tell astronomers a great deal about the star. It's like a finger print or bar code that tells information about the star's color, composition, and surface temperature.
Look at Star 1's absorption spectrum:
How many lines do you see in the spectrum? __________
Compare the neutralHydrogen spectrum (bottom) to the Star spectrum (top). Do some of the lines on the two spectra match up? __________
Compare the neutral Helium spectrum (bottom) to the Star spectrum. Do some lines match? __________
Based on this information, does Star 1 contain neutral hydrogen and helium? __________
Consider the following spectra, with Star 2's on top and the element's spectra underneath.
Neutralized magnesium
Neutralized calcium
Neutralized sodium
Neutralized iron
Neutralized magnesium
Which elements have contributed to the spectrum of Star 2?
neutralized sodium
neutralized magnesium
neutralized calcium
neutralized iron
Consider the following spectra, with Star 2's on top and the element's spectra underneath.
Neutralized hydrogen
Ionized hydrogen
Ionized sodium
Ionized calcium
Which elements have contributed to the spectrum of Star 4?