Download Section 8.1 Answer Key

Section 8.1 Check and Reflect Answers
1. (a) A constellation is a group of stars that, from Earth, forms a recognizable pattern.
(b) There are 88 official constellations.
2. A protostar is a star during its earliest stage of formation.
3. Nuclear fusion must occur inside a forming star. Then the energy from the nuclear
fusion needs to reach the star’s outside before it can “switch on” and create its own
light.
4. The mass of newly formed stars determines how the star will evolve.
5. Most stars in the universe are red dwarfs.
6. Stars are plotted by their surface temperature, their luminosity or brightness, and
their colour.
7. It revealed main sequence stars, which are those stars in the stable part of their life
cycle. It also revealed that those stars outside the main sequence are nearing the end
of their life cycle.
It also revealed that the bluest/whitest stars were the hottest, while the reddest stars
were the coolest. It revealed further that the largest ones were the brightest, while the
smallest ones were the dimmest.
8. (a) Antares is cooler.
(b) It is about 100 times more luminous.
Polaris = 10000 while Procyon A = 100, therefore 10000/100 = 100X more
luminous
(c) It will not be in the main sequence anymore  turns into a black dwarf.
10.Starting at the Big Dipper, look south to find Polaris (in Ursa Minor/Little Dipper.
11.(b), (a), (c), (d)
12.(a) Blue stars are brighter than red stars.
(b) Blue stars are hotter than red stars.
13.Sirius B will turn into a red giant, then a white dwarf, then a black dwarf if it is indeed
a medium mass star.
14.Various answers! 