DOL - 11/12 - H-R Diagram

Which stars are hotter, white dwarfs, giants, or supergiants?

Tags

NGSS.HS-ESS1-3

Which stars are brighter, white dwarfs, giants, or supergiants?

Find our sun on the graph.

Which option best describes our sun, compared to other stars?

• Our sun is one of the brightest, hottest stars

• Our sun is of medium brightness and medium temperature, compared to other stars.

• Our sun is one of the least bright and coolest stars.

• Our sun is very bright, but also quite cool.

Tags

NGSS.HS-ESS1-1

The high temperatures inside stars are produced by ​ (a)   reactions inside the core of the star. These reactions convert hydrogen to ​ (b)   .

• nuclear fusion
• helium
• nuclear fission
• iron
• carbon

Tags

NGSS.HS-ESS1-1

NGSS.HS-ESS1-3

NGSS.HS-PS1-8

• For a standard H-R diagram, what are the stars in the lower left region of the diagram?

• Main sequence stars

• Supergiants

• Giants

• White dwarfs

Answer explanation

The white dwarfs are higher in temperature than many stars, but are low in luminosity. Because temperature is represented on the horizontal axis of the H-R diagram and is reversed from the norm, the white dwarfs are in the lower left region of the diagram.

1. Stars on the upper left end of the main sequence differ from those on the lower right end in what way?

• Stars on the upper left end are less massive.

• Stars on the upper left end are more massive.

• Stars on the upper left end tend to be red in color.

• Stars on the upper left end are near the end of their life cycle.

Answer explanation

Stars that are in the upper left end of the main sequence are far more massive than those in the lower right end. They also are blue in color. All stars on the main sequence have yet to enter the final stages of their life cycles.

1. How do white dwarfs compare with supergiants, in terms of temperature and luminosity?

• White dwarfs are cooler and have higher luminosity than supergiants.

• White dwarfs are cooler and have lower luminosity than supergiants.

• • 
    White dwarfs are warmer and have higher luminosity than supergiant

• White dwarfs are warmer and have lower luminosity than supergiants.

Answer explanation

White dwarfs are positioned slightly to the left of the "giant and supergiant" region of the H-R diagram. Because the temperature axis is backwards from the norm, this makes white dwarfs warmer than supergiants. Vertically, white dwarfs are positioned much lower on the H-R diagram than supergiants. This indicates that white dwarfs have a much lower luminosity than supergiants.