The Hertzsprung Russell Diagram, Essay Example

Topic Statement

Describe the Hertzsprung-Russell diagram. Where on an H-R diagram does a star spend most of its life?

The Hertzsprung Russell Diagram

The Hertzsprung Russell Diagram is one of the most well-known diagrams in astronomy. Its graph plots the absolute magnitude against the star’s place on the color spectrum. The diagram ranges from the high temperatures of the bluish white stars to the low temperatures of the red stars (UOregon.edu, 2009). The vertical position on the diagram represents luminosity or the absolute magnitude of the star; the horizontal position indicates the temperature of the star’s surface area (Ibid).

Luminosity Classes

There are five major subdivisions within the category of star luminosity.

Supergiants

The super giant classification of luminosity are the very large and most luminous stars in the final stage of their lives (Utah.edu, 2009). Stars in this classification are very rare and include Betelgeuse and Rigel (Ibid).

Bright Giants

Bright giants are stars with a luminosity level between supergiants and normal giants, including Sargas (AtlasOftheUniverse.com, 2010).

Normal Giants

Stars in the category of ‘normal giants’ are low-mass stars that have amassed to the size of a giant (AtlasOftheUniverse.com, 2010). One example of a normal giant is Arcturus.

Subgiants

Stars classified as ‘subgiants’ are in an advanced evolutionary stage toward become a giant (AtlasOftheUniverse.com, 2010). This category contains Alnair, as one example.

Dwarfs

Finally, stars that are categorized as dwarfs are hydrogen-combusting. This is the category in which stars spend the majority of their lives (AtlasOftheUniverse.com, 2010). These stars include the Sun and Sirius (Ibid).

References

“The Hertzsprung Russell Diagram”. (2010). Retrieved on November 4, 2010 from AtlasOfTheUniverse.com: http://www.atlasoftheuniverse.com/hr.html

“Hertzsprung-Russell Diagram”. (2009). Retrieved on November 4, 2010 from UOregon.edu: http://zebu.uoregon.edu/~soper/Stars/hrdiagram.html

“Hertzsprung-Russell Diagram”. (2009). Retrieved on November 4, 2010 from Utah.edu: http://sunshine.chpc.utah.edu/labs/star_life/hr_diagram.html