Featured Resources
Classroom-Ready Activities
Science Olympiad Webinar
Science Olympiad JS9 Guide
Space Math @ NASA
NSO Tests 2024
- BirdSO In-Person Invitational
- DSM Astro Invitational
- UTexas Astro Invitational
- UTexas RFTS Invitational
Informal Education
Interactive Games
Space Scoop
STOP for Science
Chandra Podcasts
Printable Materials
Resource Request
Educators' Comments
Evaluation Form
Links & Resources
Education Collaborations
Passport to Knowledge
Space Place
Web Shortcuts
Chandra Blog
RSS Feed
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
Variable Stars

Stars appear to shine with a constant light; however, thousands of stars vary in brightness. The brightness that a star appears to have (apparent magnitude) from our perspective here on Earth depends upon its distance from Earth and its actual intrinsic brightness (absolute magnitude.) The behavior of stars that vary in magnitude (brightness) - known as variable stars - can be studied by measuring their changes in brightness over time and plotting the changes on a graph called a light curve. Amateur astronomers around the world observe variable stars and assist professional astronomers by sending their data to variable star organizations, such as the American Association of Variable Star Observers (AAVSO) in Cambridge, Massachusetts. The behavior of some variable stars can be observed with the unaided eye or binoculars. Measuring and recording the changes in apparent magnitude and drawing the resulting light curves will allow you to begin to unravel the stories of the often turbulent and always exciting lives of variable stars. The collection and study of variable star data requires the ability to estimate the apparent magnitudes of stars. The two activities that follow will assist you in acquiring the skill of estimating the magnitudes of variable stars.

The two activities, Stellar Heartbeats and A Variable Star in Cygnus, have been adapted from the "Variable Star Astronomy, Variable Stars in Math, Science, and Computer Education" curriculum project developed and published by the American Association of Variable Star Observers (AAVSO.)

Activity #1: Stellar Heartbeats html | pdf | ppt
Activity #2: A Variable Star in Cygnus html | pdf | ppt
Alignment of Performance Task with National Stardards: html | pdf

Useful Resources:

Please Note: Flash movies require the free Flash plug-in from Macromedia. PDF files require Adobe Acrobat Reader, also a free plug-in. See our Download Center for help.