Individual Assignment 3 Template
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School
University of Alabama, Birmingham *
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Course
113
Subject
Astronomy
Date
Dec 6, 2023
Type
docx
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4
Uploaded by KidGalaxy13288
The below questions follow the order of their assignment in Agenda Oct 4 – 8. Excepting the questions about the movie, the questions regard Chapter 11 in the course text.
Short Answer Questions Based on the Reading:
1.
What is the general composition of all stars, and how does composition differ among
stars in terms of elements important to planet formation and life?
The general composition of all stars is the stellar composition.
The compositions of stars at birth therefore reflect the composition of interstellar clouds, and measurements showing that these clouds have approximately the same composition throughout the universe: roughly three-quarters hydrogen and one-quarter helium, while the other elements representing only a very small proportion of the total mass. But in terms of earlier universes, the universe on contained only the chemicals hydrogen and helium.
2.
Summarize how stars differ along the spectral sequence
OBAFGKM. Why is mass the fundamental property in determining a star’s type, and how does mass affect a star’s life cycle?
Founder of the spectral sequence, Annie Jump Cannon (1863-1941). Conducting studies that resulted in the factor that there were seven different
classifying star systems that she have came up with a politically incorrect memorization “Oh, Be A Fine Girl, Kiss Me” (OBAFGKM). Suspension has aroused along with another scientist name. Cecilia Payne-Gaposchikin (1900-
1979) who pretty much came to a concluding that stars do not differ in terms
of their composition but instead their temperature. Mass is the fundamental property in determining a star’s type is by the determination of the surface temperature and luminosity throughout the stars main sequence life leading to a stars lifetime. But though mass carries importance, it can also carry a negative effect on a star’s lifetime in terms in how large the mass is; a large amount of mass can potentially shorten the life cycle of the star.
3.
Describe four criteria a star must meet to make a good “sun” that could support life,
and which types of stars meet each of these criteria. Overall, how common are such stars? Be sure to include discussion of the relevant factors in binary or multiple – star systems.
The star should contain enough elements besides H and He to have allowed for the formation of habitable worlds. The star should last long enough for life to take hold and evolve. For surface life, at least, the star should shine with steady light and should shine with steady light and should have a habitable zone in which such life could potentially arise. Though there are not rare stars that are like this, it is common enough to be discovered by scientist that have discovered 5 planets that are the size of the Earth.
To make a good “sun” for a habitable world, a star should have a high enough proportion of elements besides hydrogen and helium to allow planet formation; it should be low enough in mass that it will live long enough for life to take hold and evolve; it should be in the hydrogen-
fusing stage of life that allows for steady sunlight and a habitable zone; and if it is in a binary or multiple-star system, it should allow for stable orbits with the habitable zone.
18. How is classification useful in science? Briefly describe how our stellar classification scheme was discovered.
In 1910 – the astronomical community adopted Cannon’s system of stellar classification.
The classifications of science can be important because it allows you to make phenomenal discoveries and make efforts at uncovering understanding.
20. Briefly summarize the characteristics of stars in each of the three major regions of the H – R diagram – the main sequence, the giants and supergiant, and the dwarfs.
The main sequence
The main sequence is where the Sun falls from the upper left to the lower right of the diagram. Also, most stars are on the main sequence.
Giants and supergiant’s
Upper right stars in the H – R diagram are more luminous than main sequences. Are very large in radius.
The dwarfs
Stars in the lower left of the diagram has high surface temperature, dim luminosities, and small radii’s.
12. Summarize the key features shown in Figure 11.20, and briefly describe the nature of planets that would fit each of the model curves shown on the graph.
Metal-rich terrestrial planets or "super-Earths" have very high densities, have a smaller radius, and have a mass ranging from 1-1000 Earth units. These planets are close to the bottom of the graph because they have the smallest range in planetary radius. Next come the terrestrial planets, which are relatively high in density like the metal-rich terrestrial planets. They also tend to have smaller planet radiuses. These terrestrial planets are most like Earth and Venus. The planets rich in hydrogen compounds, or "water worlds," tend to vary in densities and masses.
14. What types of worlds seem most likely to support surface habitability? What types of worlds might have subsurface habitability?
Surface Habitability
Venus
Mars
Earth
Subsurface Habitability
Mars-like and Earth-like
Europa
Ganymede
Enceladus
Surface habitability seems possible for planets or moons similar in size and composition to Earth
and located within the habitable zone. Subsurface habitability may be even more common since it is possible on any world with enough internal heat to keep water liquid beneath the surface. Orphan planets, which do not orbit a star, also offer intriguing possibilities for subsurface life, a possibly even for surface life if they have thick enough atmospheres.
15. How might a star’s habitable zone be wider than we assume based on planets like Earth? What are orphan planets
, and how might they potentially be habitable?
A star's habitable zone might be more expansive than our solar system's habitable zone because super-Earths and water worlds can be several times as massive as Earth and can retain substantial
atmospheres of hydrogen gas from the planetary formation. This hydrogen could then be used as a greenhouse gas to keep the planets warm enough to maintain surface liquid, even when they are farther away from the star. Orphan planets are planets that do not orbit a star. These planets could be habitable because they might have an energy source from internal heat and a hydrogen atmosphere resulting in a greenhouse effect. Even so, these worlds would still not receive the high-intensity energy from a star that is necessary for life processes on Earth.
Which movie do you plan to watch?
Arrival
What is your plan for accessing the movie of choice?
I plan to use Hulu.
Extra Credit:
Would You Believe It? (questions at the end of the chapter)
22. 27. 28. 30.
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