A Stellar Investigation


What to do? Use the star information table below and spreadsheet software to answer the questions at the bottom of the page.


Background Information

For thousands of years humans have been amazed by the heavens. They have studied the skies and observed the movements of stars and constellations throughout time. The unchanging patterns seen in the constellations have provided motivation for the creation of countless myths, stories and legends. Infact, the zodiac names still in use today were originally provided by our ancient ancestors! There is no doubt to the majestic nature and beauty  that the stars and planets display in the heavens. As mankind has studied the stars through time, they have developed a number systems for naming and describing stars. Magnitude is once such system that is used to describe the brightness of a star. The magnitude scale was developed by an ancient Greek Astronomer by the name of Hipparchus around 150 B.C. The brightest stars were given a magnitude value of 1 while the dimmest stars were given a magnitude value of 6. A star with a magnitude of 1 appears 100 times brighter from earth than a star with an magnitude of 6. Today two scales of magnitude are used, they are apparent magnitude and absolute magnitude. How bright a star appears from earth is called its apparent magnitude. While absolute magnitude describes how bright a star would appear from a set distance of aproximately 32 light years. The absolute magnitude extends from -8 (extremely bright) to + 16 (extrmely dim). 

Common name Constellation Scientific name Distance in light years Absolute magnitude Apparent magnitude
Achernar Eridanus Alpha Eri 69 -1.3 0.46
Aldebran Taurus Alpha Tau 60 0.85 -0.3
Aquila Alpha Aq 1 16 2.6 0.77
Antares Scorpius Alpha Sco 520 -5.2 0.96
Arcturus Bootes Alpha Boo 34 0.2 -0.04
Betelgeuse Orion Alpha Ori 1400 -7.2 0.5
Canopus Carina Alpha Car 74 -2.5 0.72
Auriga Alpha Aur 41 0.4 0.08
Castor Gemini Alpha Gem 49 0.5 1.57
Deneb Cygnus Alpha Cyg 1500 -7.2 1.25
Pollux Gemini Beta Gem 40 0.7 1.14
Procyon Canis minor Alpha Cmi 11.4 2.6 0.38
Regulus Leo Alpha Leo 69 -0.3 1.35
Rigel Orion Beta Ori 1400 -8.1 0.12
      4.8 -26.72
Sirius Alpha Cma Canis Major 8.6 1.4 -1.46
Spica Virgo Alpha Vir 220 0.98 -3.2
Vega Lyra Alpha Lyr 25 0.6 0.03




1. Using the data in the table, make a column graph of the distance to each star (from earth) in light years.


2. Make a line graph showing the absolute magnitude and apparent magnitude for each star.


3. Make a line graph showing both the distance to each star in light years and the apparent magnitude of each star.


4. Identify the brightest star.


5. Identify the dimmest star.


6. Research using the internet and explain the difference between apparent and absolute magnitude?


7. Explain the Sun having an apparent magnitude of -26.72, but its absolute magnitude is 4.8.


8. Explain what a lower magnitude value means?


9. Write a paragraph to explains each graph (you can do this in a suitable space below each graph).


10. Examine your graphs. Are the dimmest stars closer or further away from the Earth?





STAR GRAPHS.xlsx28.43 KB