Title: Week 6 At Play in the Cosmos Assignment
Course: ASTRON103: The Evolving Universe: Stars, Galaxies, and Cosmology (001) DHH SU18 > Section: Week 6

Spectral Classification

This week, you're going to use Exploration Mode* in At Play in the Cosmos to classify the spectra of selected stars. First, read the background info; then, undertake the tasks listed. Unlike previous weeks, your progress won't automatically be transmitted to the game servers (and thence to my grade book); instead, you'll have to make a file submission, as described below in the write-up section.

* Exploration Mode can be found at the bottom of the mission list in the main menu.

Background

At Play in the Cosmos provides a Spectrum Analyzer tool for classifying the spectra of the various objects we encounter in the game. The tool works by comparing an object's spectrum against a database of spectra for known objects; by finding a match, the object can be classified.

For the most part, the Spectrum Analyzer tool works fine; however, in some instances it can go a little awry:

- sometimes, the spectrum of the object appears incorrect. For instance, the Spectrum Analyzer shows a star as having an emission spectrum (bright lines against a dark background), whereas in fact stars should exhibit absorption spectra (dark lines against a bright background).
- sometimes, the database of spectra for known objects is incorrect. For instance, a set of emission spectra can be shown even though the object has an absorption spectrum.

Tasks

In Exploration Mode, find one star of each spectral type O-B-A-F-G-K-M. During this process (which will involve running the Spectrum Analyzer tool on a number of stars), you'll likely encounter some of the problems outlined above; please be sure to note these in your write up.

For each star,

- determine whether it is a main-sequence star or a giant/supergiant;
- state what nuclear fuel it is currently "burning", and where in the star this burning is taking place
- for the main-sequence stars, predict how the star will likely end its life

Write-Up

Your final write-up should be as long as necessary (but typically 1 page or less), providing your answers to the questions given above. You don't have to show your working, but if you do it's easier to award partial credit for incorrect answers. Your write-up should be uploaded as a Microsoft Word (.doc, .docx) or Portable Document Format (.pdf) file.