Question

part 2: analyzing the h - r diagram in the essrt

1. open your earth and space science reference tables to page 4 (h - r diagram).
2. highlight the major regions labeled on the diagram: main sequence, giants, supergiants, and white dwarfs. what do you notice about the relative size of each region on the diagram?

• question: what do you notice about the relative size of each region on the diagram?

1. using a red colored pencil, trace the path of the \main sequence.\

• question: how does luminosity change as you move upward along the main sequence?

1. find the arrow along the y - axis towards increasing mass.

• trace this arrow in red. write beside it: \stars increase in mass and luminosity.\
• question: why do you think stars increase in luminosity as their mass increases?

1. using a blue colored pencil, lightly shade the area labeled \white dwarfs.\

• trace the outline of this region in blue.
• question: what does the location of the white dwarfs region on the diagram suggest about their temperature and luminosity?

1. identify the region labeled \giants\ and use a yellow colored pencil to highlight it.

• write a note next to this region that says, \giants form when low - mass stars expand after the main sequence.\
• question: based on the position of giants on the diagram, are they hotter or cooler than main sequence stars? explain your answer.

1. locate the \supergiants\ region and shade it orange.

• question: how do the luminosity and temperature of supergiants compare to those of giants?
• add a note beside this region indicating that \supergiants are evolved high - mass stars that will eventually explode as supernovae.\

Explanation:

1. The relative size of regions on the H - R diagram can vary, with the Main Sequence often being a relatively large and well - defined region compared to the others.
2. As you move upward along the Main Sequence, luminosity increases. This is because more massive stars in the Main Sequence have stronger gravitational compression, leading to higher core temperatures and more nuclear fusion, thus greater luminosity.
3. Stars increase in luminosity as mass increases because more massive stars have more material for nuclear reactions and higher core pressures and temperatures, which drive more intense fusion and higher luminosity.
4. The White Dwarfs region is located in the lower left of the H - R diagram, indicating relatively high temperature and low luminosity. High temperature because they are the remnants of stars that have exhausted nuclear fuel but are still hot, and low luminosity due to their small size.
5. Giants are cooler than main - sequence stars. On the H - R diagram, they are located to the right of the Main Sequence, which corresponds to lower surface temperatures for a given luminosity.
6. Supergiants are more luminous and generally cooler than giants. They are highly luminous due to their large size and are cooler because their large surface area spreads out the energy, resulting in a lower surface temperature compared to some smaller but more compact stars.

Answer:

1. The Main Sequence is often relatively large; other regions vary in size.
2. Luminosity increases.
3. More mass leads to more intense fusion.
4. High temperature, low luminosity.
5. Cooler. They are to the right of the Main Sequence.
6. More luminous and generally cooler.