Stellar Evolution 2021

The most important property that determines the evolution of a star is its ________________.

• temperature

• composition

• mass

• location

For a star like the Sun, the gravitational collapse of the interstellar cloud lasted for about ______________ and stopped with the ignition of the fusion reaction.

• 50–100 billion years

• 5–10 billion years

• 1 billion years

• 100 million years

• 1–10 million years

____ is the most significant force that determines the evolution of stars.

• Temperature

• Luminosity

• Energy

• Gravity

Why does a high-mass star evolve differently from a low-mass star?

• It can fuse additional elements because its core can get hotter.

• It has more material to burn so it can last longer.

• It is so bright that it drives material in space away from it so it can't gather up more fuel.

• It has a lower gravity so it can't pull in more fuel from space.

• The statement is false. High and low-mass stars evolve the same way.

The Sun's evolution from youngest to oldest stage is

• white dwarf, red giant, main sequence, protostar.

• red giant, main sequence, white dwarf, protostar.

• protostar, red giant, main sequence, white dwarf.

• protostar, main sequence, red giant, white dwarf.

Brown dwarfs are

• large terrestrial planets.

• objects massive enough to fuse deuterium but not massive enough to sustain hydrogen fusion.

• very low-mass main sequence stars.

• what is left over after a massive star ejects most of its material through a supernova.

When do we say that a star is born?

• when the interstellar cloud collapses

• when the interstellar matter achieves the Jeans instability

• when fusion of hydrogen atoms into helium atoms starts

• when the star leaves the main sequence

What stars form the slowest?

• O and B

• A and F

• G and A

• K and M

The typical temperature of an interstellar cloud that could collapse to a protostar is about _______.

• 1,500 K

• 1,000 K

• 300 K

• 10 K

A ____ is a region where jets of gas from young stars impact and heat the gas surrounding the young star.

• planetary nebula

• bok globule

• bipolar outflow

• T Tauri star