Hi Dgruss23

Thank you for the well thought out response.

I looked up the Original Russell’s plot, (I think we have the same resource (An Introduction to Modern Astrophysics by Bradley W. Carroll and Dale A Ostlie). You are right, there is an N classification.

This graph illustrates my problem with how Astronomers graph stuff. The average layman looking at the x-axis of the graph sees a series of letters that are not even in alphabetical order. I know that this is the result of historical sorting and cataloging of stars, but it makes it very hard for the layman to know what the heck is going on. It is like the scribes of Egypt writing in a language only they could know; it helped keep them in charge.

I have no complaint with Russell’s work, it represents a wonderful way to visualize that the stars are, for the most part, starting to conform to a kind of order. My complaint is that the theoreticians seem to drop the ball and let the existing order last. If you do have the mentioned reference, you will note that Figure 8.12 which is supposed to be the “theorist’s Hertzsprung-Russell diagram” is drawn with Temperature (not wave length) as decreasing as one moves along the x axis. This adherence to historical observation can lead to confusion. (This is particularly true when it comes to the proper description of the rate by which the universe is observed to be expanding.)

Again thank you for the well thought out response. I hope you are not too offended by my complaint about astronomers graphing techniques. But honestly, if you were drawing the graph to explain the relationships to someone else, wouldn’t you draw it differently? Increased temperature results in increase luminosity, a nice direct correlation. It then makes the exception for red giant stars more understandable.

Again, thanks

Snowflake.