Which of the following statements is true about Barnard's Star?
**You should know about where the Sun is located on the HR Diagram to answer this question. If you do not know where the Sun is located, scroll up to the colored diagram and you will see where the Sun is located.
Stars can be classified by their temperature and luminosity. When stars are classified by these two properties, other properties become evident. For instance, hotter stars are blue in color while cooler stars are red in color.
A diagram, known as a Hertzsprung Russell Diagram (HR Diagram), classifies stars based on their luminosity and temperature.
When stars are classified by temperature, they end up also being classified by color.
When stars are classified by luminosity, they end up also being classified by size. The bigger the star, the brighter the star.
Stars do not have to be hot to be bright.
An HR Diagram is not a graph. Look at the HR Diagram below. What do you see that tells you this is not a graph?
Look at the temperatures at the top of the diagram. The temperatures listed are not separated by the same temperature interval. They are also increasing from right to left. That means the hottest stars are on the left.
HR Diagrams are not standardized, but they are all read the same way. Take a look at the key below on the right. This key helps you to be able to read any HR Diagram you come across.
Notice that the hottest stars are actually blue. The coolest stars are red. Average stars, like our Sun, are yellow.
The hottest stars are on the left of the diagram, the coolest stars are on the right of the diagram.
The most luminous stars are located toward the top of the diagram. Luminous stars can be either hot or cool. Luminosity has to do with the size of the star. The bigger the star, the brighter the star.
Small stars can be hot. Look at the stars at the bottom of the diagram, the White Dwarfs. The White Dwarfs are small stars, so they are not bright, but they are hot.
Use the HR Diagram key above to help you answer the question below.
Two stars are identified on the Hertzsprung-Russell diagram below. Based on this diagram, how do the temperature and luminosity of Star 1 and Star 2 compare?
Star 1 is hotter and brighter than Star 2. Star 2 is has similar characteristics to our Sun, our Sun would be slightly cooler than Star 2.
This HR Diagram has no temperatures listed. You can still read it, you just need your handy dandy key to the right.
Which Spectral Class are the coolest brightest stars in?
Handy dandy HR Diagram key
Using the key, you know cool stars are on the right side of the diagram, and bright stars are at the top of the diagram. You do not need to know what a Spectral Class is to answer this question. Locate the area where the cool bright stars are, and then follow that down to Spectral Class M.
When You Have Completed the Question Below, Click Next
Which of the following statements is true about Barnard's Star?
**You should know about where the Sun is located on the HR Diagram to answer this question. If you do not know where the Sun is located, scroll up to the colored diagram and you will see where the Sun is located.
Barnard's Star is hotter than the Sun, and not as bright.
Barnard's Star is hotter and brighter than the Sun.
Barnard's Star is cooler than the Sun, and not as bright.
Barnard's Star is the same temperature and brightness as the Sun.