How a star's mass decides its life

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   Star card with two branching paths split at about 8 Sun masses. A star of 1 Sun mass runs out of hydrogen in its core. Which path does it follow, by Ari's reading?

   • Red giant → planetary nebula → white dwarf
   • Back to a protostar
   • Straight to a black hole
   • Red supergiant → supernova → neutron star
2. 2.

   White dwarf below about 8 Suns; neutron star about 8 to 20; black hole about 20 or more. A star of 15 Sun masses runs out of fuel. Which ending fits it, by Bo's reading (NASA)?

   • It fades with no change
   • A supernova, leaving a neutron star
   • A planetary nebula and a white dwarf
   • A black hole with no supernova
3. 3.

   Star card with two branching paths split at about 8 Sun masses (sources give 7 to 10). Which stars end their lives as supernovas, by Kira's reading?

   • The smallest, dimmest stars
   • Stars below 1 Sun mass
   • Stars of any mass, the Sun included
   • Stars above about 8 Sun masses
4. 4.

   NASA says a supernova from a star of about 8 to 20 Sun masses leaves a city-sized, superdense remnant. What is it, by Luz's reading?

   • A white dwarf
   • A neutron star
   • A black hole that pulls in the whole galaxy
   • A red giant
5. 5.

   Drawing of a dark circle outlined by a thin ring of light. Which description of a black hole matches NASA's, by Milo's reading?

   • A remnant whose gravity is so strong that light cannot escape
   • A hole torn in space that pulls in everything in the galaxy
   • A star that stopped shining and became a white dwarf
   • A dark, cold planet
6. 6.

   “Three stage cards, shuffled:” Which order begins a star's life, by Noah's reading (NASA)?

   • Cloud of gas and dust → protostar → main sequence
   • Supernova → protostar → main sequence
   • Protostar → cloud → main sequence
   • Main sequence → protostar → cloud
7. 7.

   Star card cutaway of a protostar with its core marked. When does a protostar become a main-sequence star, by Pia's reading (NASA)?

   • When it first glows from shrinking
   • When its core is hot and dense enough to fuse hydrogen
   • When it explodes
   • When it becomes a red giant
8. 8.

   Which of these stars stays on the main sequence longest, by Tala's reading?

   • Each lasts the same time
   • A 20-Sun-mass star
   • A 0.5-Sun-mass star
   • A 5-Sun-mass star
9. 9.

   Why do massive stars have short lives, by Zee's reading (NASA)?

   • They explode while still protostars
   • They have less fuel to start with
   • They use their fuel far faster
   • They use fuel more slowly
10. 10.

    NASA says some massive stars live a few million years, while the Sun gets about 10 billion. Which statement fits, by Esme's reading?

    • Mass has no effect on life span
    • Heavier stars live longer
    • The Sun will live a few million years before it fades
    • Heavier stars have shorter main-sequence lives