Star Regulations with Regulus

In class, as we continued our studies on stars, we learned that naturally there are a plethora of stars that exist in our universe and with each star there are very distinct characteristics and traits that may set them apart from one another. A way that allows scientists to organize all of these different types of stars and not confuse them with other is by using a diagram called the Hertzsprung-Russell diagram. Astronomers use the H-R diagram to study the different properties of stars.

In, “Regulus: Heart of the Lion“, Larry Session reports on the properties of the star, Regulus. Taking into consideration facts like “Regulus pumps out nearly 350 times as much energy as our sun”, its “spectral type B7V”, and has a surface temperature of about 12,000K, we can determine where it lies on an H-R diagram.


This is what an H-R diagram looks like. It splits the categories of stars into four main categories: Main Sequence stars, Red Giants, Supergiants, and White dwarfs.

The H-R diagram organizes stars based on four different measurements/classifications, their luminosity level, surface temperature, spectral type, and absolute magnitude. In the H-R diagram lecture tutorial we completed in class, we found that there was a relationship between spectral types and temperature, and absolute magnitude and luminosity. Stars of the same spectral type have the same temperature and stars with the same absolute magnitude have the same luminosity (energy output).

From what we know about Regulus, we can confirm that it must be a main sequence star. Main sequence stars follow a trend where the higher the temperature, the higher the luminosity. As previously mentioned, its spectral type is B7v and it maintains an average surface temperature of 12,000K, which means it would be located somewhere near star Sirius A on the Main Sequence in the diagram above.

According to the article, “Regulus pumps out 350 times more energy than our sun”. As a main sequence star, the higher the luminosity, the higher the temperature, as well as size. In this picture, you can see Regulus is a lot bigger than our Sun.

I think it was really neat to find out these facts about stars and the different types there are in the universe. Before this conceptual objective, I did have a difficult time keeping star properties straight in my head and how the different relations between luminosity and mass were like. With the H-R diagram, I was able to categorize and recognize the different traits and truly understand the properties of stars. Also, from the article, I was able to learn new facts about the star Regulus which I’ve come to really appreciate since before this conceptual objective as well as before I took astronomy, the only stars are I was aware of was the Sun and the North Star. By reading up more information about Regulus, I’ve expanded my knowledge and the feeling is really satisfying.

The H-R diagram is very important tool astronomers use to not only categorize stars but also use it to track stars’ lifetimes as we learn in a later conceptual objective. For now, it’s essential to understand how to read an H-R diagram as it tells us so many things about stars from just four different properties on the listed graph. It may also assist us in future star findings because by identifying a stars’ traits and placing it on the diagram, it helps to link the new star to stars astronomers has identified with similar traits.


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