Which of these can a star become at the end of its evolution? Choose the three correct answers.
Which stages do all stars have in common in their life cycles?
Use the diagram to answer the question.
The life trajectory of a stellar nebula is shown. The stellar nebula, a purple gas ball turns into an average star, depicted as a yellow circle, within 500 million years. The average star turns into a red giant, depicted as a medium sized red circle, within 10000 million years. The red giant turns into a planetary nebula, a bright star surrounded by green and blue gases, within 1000 million years. And the planetary nebula gradually cools into a white dwarf, depicted as a small white circle. The stellar nebula can also turn into a massive star, depicted as a medium blue circle, within 0.1 million years. The massive star turns into a red supergiant, depicted as a large orange circle, within 15 million years. The red supergiant turns into a supernova, a bright white star, within 1 million years. The supernova can either turn into a neutron star, depicted as a yellow sphere with white rays coming out of its sides, or a black hole, a small black circle surrounded by purple rays.
Based on the diagram, which statements about stellar evolution are true? Select the two correct answers.
Which is a possible sequence in the life cycle of a massive star?
nebula, protostar, star, super red giant, supernova, neutron star
nebula, protostar, star, super red giant, supernova, neutron star
super red giant, protostar, nebula, star, neutron star, supernova
super red giant, protostar, nebula, star, neutron star, supernova
planetary nebula, super red giant, protostar, supernova, star, black hole
planetary nebula, super red giant, protostar, supernova, star, black hole
supernova, star, black hole, planetary nebula, super red giant, protostar
To determine which options are correct, let's first understand the different stages of stellar evolution.
1. Main Sequence Star: This is the phase when a star is actively burning hydrogen in its core, like our Sun. It is the longest and most common phase in a star's life.
2. Red Giant: As a star exhausts its hydrogen fuel, it starts to expand and becomes a red giant. During this phase, the star fuses helium in its core.
3. White Dwarf: After a red giant sheds its outer layers, what remains is a dense core called a white dwarf. It consists mainly of carbon and oxygen. White dwarfs gradually cool down over billions of years until they no longer emit significant light.
4. Neutron Star: When massive stars (8-20 times the mass of the Sun) exhaust their nuclear fuel, they undergo a supernova explosion. This explosion can leave behind a highly dense neutron star composed mainly of neutrons.
5. Black Hole: In the most extreme cases, stars with masses greater than 20 times that of the Sun can collapse into a singularity, creating a black hole with intense gravitational pull from which light cannot escape.
Now, as for the correct answers, based on the above information, the three options that can represent the end of stellar evolution are:
1. White Dwarf: A star can become a white dwarf at the end of its evolution if it is of low to medium mass.
2. Neutron Star: A star can become a neutron star if it is massive enough and undergoes a supernova explosion.
3. Black Hole: A star can collapse into a black hole if it is extremely massive, typically greater than 20 times the mass of the Sun.
Therefore, the correct answers are white dwarf, neutron star, and black hole.