Stars Elements and Their Spectral Fingerprint HertzsprungRussell Diagram

Stars, Elements and Their Spectral Fingerprint

Hertzsprung-Russell Diagram

Hertzsprung-Russell Diagram © National Schools' Observatory : 2004 - 2016

Hertzsprung-Russell Diagram • How to read the diagram – Luminosity = Magnitude = brightness (y-axis) – Surface Temperature (x-axis) – Hottest and brightest are towards the top left – Cooler and dimmer towards the bottom right

Hertzsprung-Russell Diagram Questions 1. What color are cooler stars? 2. What color are hot stars? 3. What category of star is our sun?

Electromagnetic spectrum • Stars emit all forms of electromagnetic energy. • We can only see a very small part of it = visible light = colors. © 2015 Pro. Documentary

Short wavelength Long wavelength

Visible light questions: 1. What colors are on the visible light spectrum? 2. What units are the wavelengths of light measured in? 3. What is the range of wavelengths of visible light? 4. Which color has the longest wavelength? 5. Which color has the shortest wavelength?

Each element, when illuminated, gives off a unique set of spectral lines called a “spectral fingerprint”.

1. Hydrogen Purple: 410 Violet: 434 Blue: 486 Red: 656

2. Helium 667 587 501 492 471 447 402

Questions: 1. What is a spectral fingerprint? 2. How does it help us understand stars?

Reminder On the Color the Spectrum Activity—don’t forget to do the back!!