What can spectra tell us about temperature?
Stars are too far away (and too hot!) for a human to touch, yet we can measure their temperatures. Spectra make this possible! Let’s investigate how.Stars Part 1: Spectra
Spectrum Tool.
- Use the Select star dropdown menu to view the spectrum of each star: the Sun, an M star, and a B star.
Spectrum Notebook. For each spectrum, complete the steps below to fill in the Table in your Notebook.
- At what wavelength does the star emit the most light?
Hint 1: Where is the y-value roughly the highest?
Hint 2: Adjust the wavelength stretch as needed, so you can see all the available data. Under normalize data, select all or none
- What is the energy associated with the wavelength that emits the most light?
Hint: Use the units dropdown to select electron volts, then use the vertical measuring tool to determine the energy.
- Based on the brightness of light across the visible part of the spectrum, what color would you expect this type of star to appear?
Hint: For the M star and B stars, under normalize data, select visible.
Simulation. If you would like a refresher on how light colors mix, double-click the "RGB Bulbs" to launch the PhET Color Mixing simulation at the bottom of the page.
Note: The simulation is not a perfect proxy for what you would see in real life, because it does not include all colors that exist in the visible spectrum. You can still approximate the colors you would see by adjusting the percentages for R, G, and B to roughly match the brightness of the light (shown on the y-axis) for each band of color in the spectrum.
Brightness 