Classroom Questions

Questions for “Strange but true: White dwarfs shrink as they gain mass”

planetary nebula NGC 2440

White dwarfs, like the one inside NGC 2440, the planetary nebula pictured here, have a strange property. The more mass these super-dense stars gain, the smaller they get.

K. Noll/STScI, ESA, NASA

By Science News Explores

To accompany “Strange but true: White dwarfs shrink as they gain mass”

SCIENCE

Before Reading:

1. Describe what you know about the life cycle of a star: how it comes into being, burns brightly and then dies. You can learn more in our Explainer: Stars and their families.

2. Many stars are described as “dwarfs.” Why might that be an odd term for a star?

During Reading:

1.  What are white dwarfs?

2.  What was the odd trend noted in white dwarfs that gain more mass?

3.  Did this observation surprise astronomers? Explain your answer.

4.  What are supernovas and how do these appear to relate to white dwarfs?

5.  Why has measuring the mass of a solo white dwarf been tricky?

6.  Consider a white dwarf with slightly more mass than our sun’s. How will its size compare to Earth’s size?

After Reading:

1.  Read about the life cycle of stars. Is it likely our sun will ever become a white dwarf? Are white dwarfs even common?

2. What did you find most surprising in this story? If you could move a telescope to point anywhere in the sky, what would you most like to observe with it? Explain why.