Astronomy 200/210
Lab Project #2 - Stellar Classification


The purpose of this project is to give you experience in interpreting stellar spectra and to better understand the stellar spectral classification system. In preparation for this project you are encouraged to review the following lectures:

Stellar Spectra

Stellar Classification

How to Use the Applet Spectral Analysis

In class we will look at the applet Spectral Analysis and how you are expected to use it. You may find the following videos helpful to refresh your memory on how to use the applet and interpret spectra.


Video 1: Quick overview of the applet
 Video 2: Identifying spectral lines - part 1
 Video 3: Identifying spectral lines - part 2

What to Do...

Load the applet (this link will open in a separate window) and analyze each of the 15 spectra. On the answer form (see below) identify the spectral types. Included in the spectra are all of the 7 major classes (O,B,A,F,G,K,M) as well as:

  1. The Wolf-Rayet star WR 136 - this is the left-over inner part of a highly evolved star and has a surface temperature of about 70 000 K! It shows very strong emission lines of Hydrogen, Helium and Oxygen with other elements also in emission.
  2. The symbiotic star CH Cygni - this is a cool M giant star that shows some strong Hydrogen emission lines due to its interaction with a White Dwarf companion star.
  3. The star Sheliak - this is a hot star that shows both emission and absorption lines.
  4. The star gamma Cassiopeia - an extremely hot star (about 30 000 K) with very strong Hydrogen emission lines and very few if any absorption lines.

Due Date:

The lab is due 1 week from today - NO EXTENSIONS